Symptom Table

WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.

Symptom	Possible Cause	Action	Reference
Engine Difficult to Start or Will Not Start (No Exhaust Smoke)	Low fuel level in the fuel tank	Verify sufficient fuel level in the fuel tank. Verify the fuel gauge is working properly.	-
	Low fuel rail pressure	Attempt to start the engine by engaging the starter motor for at least 30 continuous seconds. Use CONSULT to monitor FUEL RAIL PRESSURE and FUEL RAIL PRESS CMD. Use CONSULT to check for DTCs. Attempting to start the engine for 30 continuous seconds allows the DTC logic time to run. If DTC P0087 or P008A becomes current, fuel rail pressure is not being developed. Follow DTC diagnosis as appropriate.	CONSULT Function DTC Index
	Stage 2 fuel filter plugged	Check for a plugged or restricted pressure-side fuel filter. Check fuel filter maintenance schedule. Replace filters if needed.	Low-Pressure System Check Removal and Installation
	Fuel drain-back to the fuel tank	Verify all suction side fuel line connections are tight and air is not allowed to enter the fuel system. Verify the Stage 2 fuel filter is tight.	-
	Air in fuel system	Check for air in the fuel system. Bleed the fuel system and correct the source of the leak.	Priming
	Fuel drain line not routed to the bottom of the fuel supply tank	Verify the fuel drain line is routed correctly to the bottom of the fuel tank. If the drain line is not routed to the bottom of the tank, air is allowed to enter the fuel system and the fuel will drain back to the tank on the suction side of the pump. This will cause a hard start condition after the engine is turned OFF for an extended period of time.	-
	Plugged fuel tank vent	Remove the fuel tank cap. If the engine starts properly with the fuel cap removed, inspect the fuel tank vent for plugging or restriction.	-
	Poor fuel quality or wrong fuel grade	Verify fuel specifications by operating the engine from a tank of known high quality fuel grade. Check for DEF contamination in the fuel. Analyze fuel sample to check for DEF or water.	-
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine and isolate the misfire. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Fuel lift pump malfunction	Check the fuel lift pump for correct operation. Check the pump output pressure. Replace the lift pump, if necessary.	Low-Pressure System Check
	Malfunctioning glow plug	Check for glow plug DTC's and troubleshoot as necessary.	DTC Index
	Coolant temperature sensor is malfunctioning	Check coolant temperature sensor for proper operation.	Engine Coolant Temperature Sensor
	Crankshaft position sensor is malfunctioning	Check CKP sensor for proper operation.	Component Inspection
	Camshaft position sensor is malfunctioning	Check CMP sensor for proper operation.	Camshaft Position Sensor
	Malfunctioning ECM power or ground circuit	Check the battery voltage of the ECM power supply and ground circuit.	Diagnosis Procedure
	Malfunctioning key switch circuit	Check key switch circuit for intermittent connections.	Intermittent Incident
	Low battery voltage	Check battery by measuring voltage between positive (+) and negative (-) battery terminals while trying to start the engine.	Work Flow
	Slow cranking speed	The minimum cranking speed must be greater than 150 RPM.	-
	High exhaust restriction	Inspect the exhaust system for restrictions and/or measure the exhaust restriction.	Checking Exhaust System
	Nissan Anti-Theft System	Check NATS.	Work Flow
Engine Starts But Will Not Keep Running	Current DTCs or high counts of past DTCs	Troubleshoot current or past DTCs.	DTC Index
	Fuel level is low in the tank	Fill the supply tank.	-
	Air in fuel system	Check for air in the fuel system. Bleed the fuel system and correct the source of the leak.	Priming
	Fuel grade is not correct for the application or the fuel quality is poor	Verify fuel specifications by operating the engine from a tank of known high quality fuel grade. Check fuel sample for presence of contaminant. Check for DEF contamination in the fuel. Analyze fuel sample to check for DEF or water.	-
	Low fuel rail pressure	Attempt to start the engine by engaging the starter motor for at least 30 continuous seconds. Use CONSULT to monitor FUEL RAIL PRESSURE and FUEL RAIL PRESS CMD. Use CONSULT to check for DTCs. Attempting to start the engine for 30 continuous seconds allows the DTC logic time to run. If DTC P0087 or P008A becomes current, fuel rail pressure is not being developed.	CONSULT Function DTC Index
	Fuel inlet restriction	Check for fuel inlet restriction.	Low-Pressure System Check
	Fuel lift pump is malfunctioning	Check the fuel lift pump for correct operation. Check the pump output pressure. Replace the lift pump, if necessary.	Low-Pressure System Check
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	MAF sensor malfunction	Test MAF Sensor to verify proper operation.	Component Inspection
	Coolant temperature sensor is malfunctioning	Check coolant temperature sensor for proper operation.	Engine Coolant Temperature Sensor
	Crankshaft position sensor is malfunctioning	Check CKP sensor for proper operation.	Component Inspection
	Idle shutdown features are activated	Turn the key switch OFF for 5 seconds. Turn the key switch ON and check MIL operation. Use CONSULT to check the Idle Shutdown.	CONSULT Function
	Battery voltage is low	Check the batteries and the unswitched battery supply circuit.	Work Flow
	Vehicle electrical parasitics are excessive	Check for transmission malfunctioning, cooling fan operation cycle time, and engine-driven units.	-
	Key switch circuit is malfunctioning	Check the key switch circuit.	Diagnosis Procedure
	Turbocharger restriction	Check for exhaust restrictions at the turbocharger to exhaust manifold connection. Replace the turbocharger, if necessary.	Removal and Installation
	After treatment restriction	Check DOC/DPF and SCR for restrictions or damage.	Exploded View
Engine Runs Rough or Misfires	Poor fuel quality or fuel additives	Operate the engine with a known high quality fuel supply and determine if the performance symptoms are eliminated. Verify if the customer is using any fuel additives that could cause rough running complaints. Check for DEF contamination in the fuel. Analyze fuel sample to check for DEF or water in fuel.	-
	Low fuel rail pressure	Attempt to start the engine by engaging the starter motor for at least 30 continuous seconds. Use CONSULT to monitor FUEL RAIL PRESSURE and FUEL RAIL PRESS CMD. Use CONSULT to check for DTCs. Attempting to start the engine for 30 continuous seconds allows the DTC logic time to run. If DTC P0087 or P008A becomes current, fuel rail pressure is not being developed.	CONSULT Function DTC Index
	Air in fuel system	Check for air in the fuel system. Bleed the fuel system and correct the source of the leak.	Priming
	Fuel drain line restriction	Check for a blocked or restricted fuel drain line.	Low-Pressure System Check
	High fuel inlet restriction	Perform the Fuel Inlet Restriction Test.	Low-Pressure System Check
	Stage 2 fuel filter plugged	Check for a plugged or restricted pressure-side fuel filter. Check fuel filter maintenance schedule. Replace filters if needed.	Low-Pressure System Check Removal and Installation
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Malfunctioning fuel pump actuator	Perform CONSULT High-Pressure Fuel System Actuator test to determine if the fuel pump actuator has malfunctioned.	High-Pressure Fuel System Actuator Override Test
	Stuck open exhaust gas recirculation (EGR) valve	Use CONSULT to perform the After treatment Selective Catalytic Reduction Regeneration Test. Allow the stationary regeneration procedure to run a minimum of 5 minutes. Use CONSULT to monitor EGR VALVE POS and EGR VALVE POS CMD. Verify that both values match each other during the DPF Regeneration Test. Troubleshoot any active DTCs if the values do not match.	CONSULT Function
	Coolant temperature sensor is malfunctioning	Check coolant temperature sensor for proper operation.	Engine Coolant Temperature Sensor
	Crankshaft position sensor is malfunctioning	Check CKP sensor for proper operation.	Component Inspection
	Worn or damaged hydraulic lash adjusters	Inspect hydraulic valve adjuster for excessive wear or damage.	Exploded View
	Valve stem clearance is excessive or the valve stem seals are damaged	Check the valve stems and seals.	Exploded View
	Cylinder head valve guides are excessively worn	Check the valve guides for wear. Replace the cylinder head, if necessary.	Exploded View
	Piston or piston rings are worn or damaged	Check for air intake system leaks. Check the pistons and piston rings for wear or damage. Perform compression test.	Compression Check
	After treatment restriction	Check DOC/DPF and SCR for restrictions or damage.	Exploded View
Engine Speed Surges Under Load or in Operating Range	Current DTCs or high counts of past DTCs	Using CONSULT, check for DTCs.	DTC Index
	Air in fuel system	Check for air in the fuel system. Bleed the fuel system and correct the source of the leak.	Priming
	High fuel inlet restriction	Perform the Fuel Inlet Restriction Test.	Low-Pressure System Check
	Fuel drain line restriction	Check for a blocked or restricted fuel drain line.	Low-Pressure System Check
	Malfunctioning fuel pump actuator	Perform CONSULT High-Pressure Fuel System Actuator test to determine if the fuel pump actuator has malfunctioned.	High-Pressure Fuel System Actuator Override Test
	Stage 2 fuel filter plugged	Check for a plugged or restricted pressure-side fuel filter. Check fuel filter maintenance schedule. Replace filters if needed.	Low-Pressure System Check Removal and Installation
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	MAF sensor malfunction	Test MAF Sensor to verify proper operation.	Component Inspection
	Accelerator Pedal Position (APP) Sensor malfunction	Test Accelerator Pedal Position (APP) Sensor to verify proper operation.	Accelerator Pedal Position Sensor
	Crankshaft position sensor is malfunctioning	Check CKP sensor for proper operation.	Component Inspection
	Stuck open exhaust gas recirculation (EGR) valve	Use CONSULT to perform the After treatment Diesel Particulate Filter Regeneration Test. Allow the stationary regeneration procedure to run a minimum of 5 minutes. Use CONSULT to monitor EGR VALVE POS and EGR VALVE POS CMD. Verify that both values match each other during the DPF Regeneration Test. Troubleshoot any active DTCs if the values do not match.	CONSULT Function
	High turbocharger compressor intake temperatures	The compressor intake temperature should be within a few degrees of ambient outside temperature. If a temperature increase is detected between the air cleaner (ambient outside temperature) and the compressor intake temperature, investigate the cause of the temperature increase.	-
Engine Speed Surges in Cruise Control	Current DTCs or high counts of past DTCs	Check for current or past DTCs.	DTC Index
	Fuel grade is not correct for the application or the fuel quality is poor	Verify fuel specifications by operating the engine from a tank of known high quality fuel grade. Check fuel sample for presence of contaminant. Check for DEF contamination in the fuel. Analyze fuel sample to check for DEF or water in fuel.	-
	Fuel level is low in the tank	Fill the supply tank.	-
	Air in fuel system	Check for air in the fuel system. Bleed the fuel system and correct the source of the leak.	Priming
	Fuel leak	Check the fuel lines, fuel connections, and fuel filters for leaks. Check the fuel lines to supply tank.	-
	Fuel pump is malfunctioning	Perform CONSULT High Pressure Fuel System Actuator Test to determine if the fuel pump actuator has malfunctioned.	High-Pressure Fuel System Actuator Override Test
	Fuel inlet restriction	Check the flow through the Stage 1 and Stage 2 fuel filters. Check maintenance schedule for fuel filters. Replace the fuel filters, if necessary.	Low-Pressure System Check
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Injectors are not correct	Verify the injector part numbers. Replace the injector(s), if necessary.	Exploded View
	Other devices on the CAN network are interfering with the engine controls	Alternately disconnect all other devices from the CAN network until communication or functionality is restored.	Refer to appropriate wiring diagram Refer to appropriate wiring diagram Refer to appropriate wiring diagram
	Moisture in the wiring harness connectors	Dry the connector with electrical contact cleaner. Replace pins or connectors as needed.	How to Check Terminal
	Vehicle parasitics are excessive	Check the vehicle for brakes dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units.	-
	Accelerator pedal is restricted or malfunctioning	Check the percent accelerator pedal reading with the CONSULT. Verify that it reads 100 percent with the accelerator pedal depressed and 0 percent when released. Replace the accelerator pedal if necessary.	CONSULT Function
	Output shaft speed sensor or circuit malfunction	Check output shaft speed sensor.	Diagnosis Procedure
	Turbocharger malfunctioning	Use CONSULT to perform the "RTCV Hysteresis Test" to verify if the turbocharger nozzle is moving properly. If the "RTCV Hysteresis Test" results in an output of "Fail", replace the turbocharger. If the "RTCV Hysteresis Test" results in an output of "Pass", this indicates that the sector gear movement is acceptable and the actuator should not be removed.	CONSULT Function
	Vibration damper is damaged or loose	Inspect the vibration damper.	Exploded View
	Flywheel housing is not aligned correctly	Check the flywheel housing alignment.	Exploded View
	Transmission damaged	Problem is related specifically to the transmission.	Work Flow
	Internal engine damage	Analyze the oil and inspect the filters to locate an area of probable damage.	-
Knock / Detonation	Current DTCs or high counts of past DTCs	Check for current or past DTCs.	DTC Index
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine and isolate the misfire. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Crankshaft position sensor is malfunctioning	Check CKP sensor for proper operation.	Component Inspection
	Progressive damage from excessive black smoke caused from an earlier or present malfunction	Review the repair history of the engine to determine if the after treatment diesel particulate filter was replaced or needs to be replaced.	Exploded View
	Extended operation of engine in low duty cycle, extended idling, and/or low ambient temperatures	Perform a stationary regeneration with CONSULT.	After treatment DPF Regeneration Test
	Engine is being lugged down	Use a lower gear.	-
	Intake air restriction is high	Check the air intake system for restriction.	-
	Excessive internal oil consumption	Check for excessive internal oil consumption.	-
	Excessive automatic or stationary regeneration	Check for excessive automatic or stationary regeneration.	After treatment DPF Regeneration Test Exploded View
Lack of Power / Poor Acceleration	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Fuel supplement/additive used has high ash content.	Discontinue use of the fuel supplement/additive being used.	-
	Low fuel rail pressure	Attempt to start the engine by engaging the starter motor for at least 30 continuous seconds. Use CONSULT to monitor FUEL RAIL PRESSURE and FUEL RAIL PRESS CMD. Use CONSULT to check for DTCs. Attempting to start the engine for 30 continuous seconds allows the DTC logic time to run. If DTC P0087 or P008A becomes current, fuel rail pressure is not being developed.	CONSULT Function DTC Index
	Stage 2 fuel filter plugged	Check for a plugged or restricted pressure-side fuel filter. Check fuel filter maintenance schedule. Replace filters if needed.	Low-Pressure System Check Removal and Installation
	Fuel lift pump is malfunctioning	Check the fuel lift pump for correct operation. Check the pump output pressure. Replace the lift pump, if necessary.	Low-Pressure System Check
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine and isolate the misfire. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	MAF sensor malfunction	Test MAF Sensor to verify proper operation.	Component Inspection
	Crankshaft position sensor is malfunctioning	Check CKP sensor for proper operation.	Component Inspection
	Camshaft position sensor is malfunctioning	Check CMP sensor for proper operation.	Camshaft Position Sensor
	Coolant temperature sensor is malfunctioning	Check coolant temperature sensor for proper operation.	Engine Coolant Temperature Sensor
	Accelerator Pedal Position (APP) Sensor malfunction	Test Accelerator Pedal Position (APP) Sensor to verify proper operation.	Accelerator Pedal Position Sensor
	Exhaust gas recirculation (EGR) valve is leaking	Check the EGR valve for leaks.	Exploded View
	Engine lubricating oil in fuel	Confirm if engine lubricating oil is mixed with fuel. Drain fuel and replace with clean fuel. Discontinue practice of mixing oil with fuel.	-
	Excessive internal oil consumption	Check for excessive internal oil consumption	-
	Crankcase pressure is excessive	Check for excessive blow-by.	-
	Air cleaner and duct	Check the intake air system for improper air flow. Inspect for restriction in air cleaner element, seal, and crushed air ducts.	-
	After treatment restriction	Check DOC/DPF for excessive soot loading or other damage.	Exploded View
Engine Decelerates Slowly	Current DTCs or high counts of past DTCs	Check for current or past DTCs.	DTC Index
	Air in fuel system	Check for air in the fuel system. Bleed the fuel system and correct the source of the leak.	Priming
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Accelerator pedal is restricted or malfunctioning	Check the percent accelerator pedal reading with CONSULT. Verify that it reads 100 percent with the accelerator pedal depressed and 0 percent when released. Replace the accelerator pedal if necessary.	CONSULT Function
	Turbocharger oil seal is leaking	Check the turbocharger compressor and turbine for signs of oil residue from seals. Repair or replace turbo as needed.	Exploded View
	After treatment system	Check DOC/DPF for oil contamination.	Exploded View
Engine Will Not Shut Off	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Fuel lift pump is malfunctioning	Check the fuel lift pump for correct operation. Check the pump output pressure. Replace the lift pump, if necessary.	Low-Pressure System Check
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Accelerator Pedal Position (APP) Sensor malfunction	Test Accelerator Pedal Position (APP) Sensor to verify proper operation.	Accelerator Pedal Position Sensor
	Key switch circuit is malfunctioning	Check the key switch circuit.	Diagnosis Procedure
	Turbocharger oil seal is leaking	Check the turbocharger compressor and turbine for signs of oil residue from seals. Repair or replace turbo as needed.	Exploded View
	Engine is running on fumes drawn into the air intake	Check the air intake ducts. Locate and isolate the source of the fumes. Repair as necessary.	Inspection
	ECM is malfunctioning	Replace the ECM.	Removal and Installation
Engine Fan Does Not Operate, Operates Erratically, or Operates Continuously	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Coolant temperature sensor is malfunctioning	Check coolant temperature sensor for proper operation.	Engine Coolant Temperature Sensor
	Fan clutch actuator or circuit is malfunctioning	Check the fan clutch actuator circuit.	Fan Clutch Assembly
	Engine electrical ground is malfunctioning	Check engine ground to chassis and chassis ground to battery negative (-) post.	-
	Intake manifold temperature or coolant temperature is above the threshold to activate the cooling fan.	Check for intake manifold temperature or coolant temperature above the threshold to activate the cooling fan.	-
Malfunction Indicator Lamp (MIL) Does Not Illuminate	Key switch is in the OFF position	Turn the key switch to the ON position.	-
	Key switch circuit is malfunctioning	Check the key switch circuit.	Diagnosis Procedure
	MIL circuit is malfunctioning	Check the MIL circuit.	Malfunction Indicator Lamp (MIL) Malfunction Indicator Lamp (MIL)
Fuel Consumption Excessive	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Aggressive driving technique with quick starts/stops	Explain correct engine operation to the operator.	-
	Engine idle time is excessive	Check the idle time with CONSULT. Low oil and coolant temperatures can be caused by excessive idle time (greater than 10 minutes).	CONSULT Function
	After treatment system active regeneration time is excessive	Check the after treatment system trip information with CONSULT. Low duty cycle applications can possibly require more active regeneration time to keep the after treatment system functioning correctly. Change the vehicle route and/or duty cycle to increase the load on the engine, in order to decrease the amount of active regeneration time. Check DOC/DPF and SCR for plugging or contamination. Refer to Exploded View	CONSULT Function
	Fuel grade is not correct or fuel quality is poor	Operate the engine from a tank of known high quality fuel. Check for DEF contamination in the fuel. Analyze fuel sample to check for DEF in fuel.	-
	Fuel leak	Check the fuel lines, fuel connections, and fuel filters for leaks. Check the fuel lines to the supply tank.	-
	Fuel lift pump is malfunctioning	Check the fuel lift pump for correct operation. Check the pump output pressure. Replace the lift pump, if necessary.	Low-Pressure System Check
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Lubricating oil level is above specification	Verify the oil level by checking the dipstick and oil pan capacity. Fill the system to the specified level.	Inspection
	Lubricating oil does not meet specifications	Change the oil and filter.	Changing Engine Oil
	Equipment and environmental factors are affecting fuel consumption	Consider ambient temperatures, wind, routes, and vehicle load when evaluating fuel consumption.	-
	Vehicle parasitics are excessive	Check the vehicle for brakes dragging, transmission malfunction, cooling fan operation cycle time, and engine-driven units.	-
	Intake manifold pressure (boost) sensor or circuit is malfunctioning	Check the boost sensor and circuit. Compare the intake manifold pressure sensor reading in the monitor mode. Use CONSULT to compare to a manual pressure gauge.	CONSULT Function
	Air intake or exhaust leaks	Inspect the air intake and exhaust systems for air leaks.	Inspection
	Air intake system restriction is above specification	Replace the air filter and inlet piping as necessary.	Exploded View
	Charge-air cooler is restricted or leaking	Inspect the charge-air cooler for air restrictions or leaks.	Exploded View
	Exhaust system restriction is not within specification	Check the exhaust system for restrictions. Check DOC/DPF and SCR for plugging or damage. Refer to Exploded View	Inspection
	Internal engine damage	Analyze the oil and inspect the filters to locate an area of probable damage.	-
Smoke, Black - Excessive	Poor fuel quality or fuel additives	Operate the engine with a known high quality fuel supply and determine if the performance symptoms are eliminated. Verify if the customer is using any fuel additives that could cause white smoke complaints.	-
	Fuel lift pump is malfunctioning	Check the fuel lift pump for correct operation. Check the pump output pressure. Replace the lift pump, if necessary.	Low-Pressure System Check
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	MAF sensor malfunction	Test MAF Sensor to verify proper operation.	Component Inspection
	Coolant temperature sensor is malfunctioning	Check coolant temperature sensor for proper operation.	Engine Coolant Temperature Sensor
	Air intake system restriction is above specification	Replace the air filter and inlet piping as necessary.	Exploded View
	Contaminated after treatment system	Inspect the after treatment diesel oxidation catalyst and after treatment diesel particulate filter for signs of coolant or lubrication oil contamination. Check the engine repair history to determine if a previous malfunction may have contaminated the after treatment diesel oxidation catalyst with coolant.	Exploded View
	Exhaust gas recirculation (EGR) valve malfunctioning	Use CONSULT to perform the After treatment Diesel Particulate Filter Regeneration Test. Allow the stationary regeneration procedure to run a minimum of 15 minutes. Use CONSULT to monitor EGR VALVE POS and EGR VALVE POS CMD. Verify that both values match each other during the DPF Regeneration Test. Troubleshoot any active DTCs if the values do not match.	After treatment DPF Regeneration Test
Smoke, White - Excessive	Poor fuel quality or fuel additives	Operate the engine with a known high quality fuel supply and determine if the performance symptoms are eliminated. Verify if the customer is using any fuel additives that could cause white smoke complaints.	-
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Malfunctioning glow plug	Check for glow plug DTC's and troubleshoot as necessary.	DTC Index
	Retained water vapor in the after treatment system	If white smoke persists after the engine has reached the minimum operating temperature, and a strong hydrocarbon odor is still present, troubleshoot the white smoke complaint.	-
	Contaminated after treatment system	Inspect the after treatment diesel oxidation catalyst and after treatment diesel particulate filter for signs of coolant or lubrication oil contamination. Check the engine repair history to determine if a previous malfunction may have contaminated the after treatment diesel oxidation catalyst with coolant.	Exploded View
	Stuck open exhaust gas recirculation (EGR) valve	Use CONSULT to perform the After treatment Selective Catalytic Reduction Regeneration Test. Allow the stationary regeneration procedure to run a minimum of 5 minutes. Use CONSULT to monitor EGR VALVE POS and EGR VALVE POS CMD. Verify that both values match each other during the DPF Regeneration Test. Troubleshoot any active DTCs if the values do not match.	CONSULT Function
	Internally leaking EGR cooler	Perform the EGR cooler leak test.	Exploded View
	Leaking cylinder head gasket	Check for a damaged cylinder head gasket.	Exploded View
	Check the injector wiring harness	Check continuity for each injector from ECM connector SIGNAL and RETURN to the appropriate injector solenoid SIGNAL and RETURN. If injector harness damage is found, it must be replaced.	Refer to appropriate wiring diagram
Fuel in the Lubricating Oil	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Engine idle time is excessive	Long idle times (greater than 10 minutes) can cause low oil and coolant temperatures which can allow oil to retain fuel. Shut the engine OFF rather than idle for long periods. If idle time is necessary, raise the idle speed. Adjust oil drain interval to prevent excessive oil contamination.	-
	After treatment system active regeneration time is excessive	Check the after treatment system trip information with CONSULT. Low duty cycle applications can possibly require more active regeneration time to keep the after treatment system functioning correctly. Change the vehicle route and/or duty cycle to increase the load on the engine, in order to decrease the amount of active regeneration time.	CONSULT Function
	Fuel drain line restriction	Check the fuel drain lines for restriction. Excessive fuel drain line restriction may result in over pressurization of the fuel pump and cause fuel to leak from the fuel pump into the engine gear housing.	Low-Pressure System Check
	Malfunctioning fuel injector	Perform CONSULT Cylinder Cutout Test to determine if the misfire can be isolated to a single injector. Perform CONSULT High-Pressure Fuel Injector Return Flow Test.	High-Pressure Fuel Injector Return Flow Test
	Bulk oil supply is contaminated	Check the bulk oil supply. Drain the oil and replace with non-contaminated oil. Change the oil filters.	-
	Internal engine damage	Analyze the oil and inspect the filters to locate an area of probable damage.	-
Intake Manifold Air Temperature Above Specification	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Fan drive or fan controls are malfunctioning	Check the fan drive and controls.	Fan Clutch Assembly
	Fan drive belt is loose	Check the belt tension and tighten, if necessary.	Inspection
	Charge-air cooler fins, radiator fins, or air conditioner condenser fins are damaged or obstructed with debris	Inspect the charge-air cooler, air conditioner condenser, and radiator fins. Clean, if necessary.	-
	Fan is damaged	Check the fan for damage. Replace the fan, if necessary.	Exploded View
	Fan shroud is damaged or missing or the air recirculation baffles are damaged or missing	Inspect the shroud and the recirculation baffles. Repair, replace, or install, as necessary.	Exploded View
	Intake manifold air temperature sensor has an in-range malfunction	Check the intake manifold air temperature sensor that corresponds to the DTC. Replace the sensor, if necessary.	Exploded View
	Vehicle speed is too low for adequate cooling with high engine load	Reduce the engine load. Increase the engine (fan) RPM by downshifting.	-
	Exhaust system leaking hot air into engine compartment	Check the exhaust plumbing for leaks or broken components.	Checking Exhaust System
	Intake manifold pressure (boost) sensor or circuit is malfunctioning	Check the boost sensor and circuit. Compare the intake manifold pressure sensor reading in the monitor mode. Use CONSULT to compare to a manual pressure gauge.	CONSULT Function
	Exhaust gas recirculation (EGR) valve is leaking	Check the EGR valve for leaks.	Exploded View
	Exhaust gas recirculation (EGR) cooler malfunctioning	Check the EGR cooler.	Exploded View
Cruise Control Does Not Operate	Output shaft speed sensor or circuit malfunction	Check output shaft speed sensor.	Diagnosis Procedure
	Stop lamp switch or circuit is malfunctioning	Check the stop lamp switch and circuit.	Refer to appropriate wiring diagram
	Cruise Control ON/OFF switch or circuit is malfunctioning	Check the Cruise Control ON/OFF switch and circuit.	Refer to appropriate wiring diagram
	Cruise Control selector switch or circuit is malfunctioning	Check the Cruise Control selector switch and circuit.	Refer to appropriate wiring diagram
Stationary Regeneration - Will Not Activate	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Soot load of the after treatment diesel particulate filter (DPF) is too low	Verify the correct stationary regeneration procedure is being followed. CONSULT can perform a stationary regeneration if the DPF lamp is illuminated or not illuminated.	After treatment DPF Regeneration Test
	The correct stationary regeneration procedure is not being followed	Verify the correct stationary regeneration procedure is being followed.	After treatment DPF Regeneration Test
	Brake pedal is depressed	The brake pedal must be released for stationary regeneration to activate. Monitor the brake pedal position switch with CONSULT and verify it is released. If necessary, check the vehicle brake switch and circuit.	CONSULT Function
	Vehicle speed is greater than zero	Stationary regeneration will not activate if the vehicle speed is greater than zero. Use CONSULT to monitor the vehicle speed while the vehicle is not moving. If the monitor shows speed, check the sensor and circuit.	CONSULT Function
	Accelerator pedal position is greater than zero	Stationary regeneration will not activate if the accelerator pedal position is greater than zero. Check for accelerator pedal or lever restriction. Use CONSULT to monitor the percent throttle reading. Check the accelerator pedal position sensor and the circuit.	CONSULT Function
	Vehicle parking brake is not set	Verify that the parking brake is set.	-
	Transmission is not in Park.	Verify that the transmission is in Park.	-
Excessive Automatic and/or Stationary Regeneration	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Extended operation of engine in low cycle, extended idling, and/or low ambient temperatures	Check the after treatment system trip information with CONSULT. Low load and low duty cycle applications generally require more active or stationary regeneration time to keep the after treatment system functioning properly. If the vehicle load and duty cycle are unable to be increased, more stationary regenerations may be needed.	CONSULT Function
	DPF differential pressure sensor	Check the functionality of the after treatment diesel particulate filter differential pressure sensor.	DPF (Diesel Particulate Filter) Differential Pressure Sensor
	Excessive soot caused by black smoke	Refer to "Smoke, Black - Excessive".	Symptom Table
	Wiring to the after treatment DPF pressure sensor is incorrect	Check for sensor pins or wires installed in the incorrect connector locations; for example, installing the SIGNAL pin in the RETURN pin location and the RETURN pin in the SIGNAL pin location. Pay special attention to the SIGNAL wires and make sure they are not swapped.	Refer to appropriate wiring diagram
	Exhaust leaks in the exhaust piping or in the after treatment system	Inspect the exhaust piping and the after treatment system for exhaust leaks.	Checking Exhaust System
	Exhaust gas recirculation (EGR) valve malfunctioning	Use CONSULT to perform the DPF Regeneration Test. Allow the stationary regeneration procedure to run a minimum of 15 minutes. Use CONSULT to monitor EGR VALVE POS and EGR VALVE POS CMD. Verify that both values match each other during the DPF Regeneration Test. Troubleshoot any active DTCs if the values do not match. Record values for the troubleshooting steps in the next step as well, while performing this CONSULT-based stationary regeneration.	After treatment DPF Regeneration Test
	Turbocharger malfunctioning	Use CONSULT to perform the "RTCV Hysteresis Test" to verify if the turbocharger nozzle is moving properly. If the "RTCV Hysteresis Test" results in an output of "Fail", replace the turbocharger. If the "RTCV Hysteresis Test" results in an output of "Pass", this indicates that the sector gear movement is acceptable and the actuator should not be removed.	CONSULT Function
	High-pressure fuel system leak, component malfunction	Check the fuel injector return flow. If return flow is excessive, isolate injectors and replace as needed.	Exploded View
	Diesel oxidation catalyst (DOC) contaminated	Inspect the diesel oxidation catalyst.	Exploded View
	After treatment DPF filter contaminated	Inspect the after treatment diesel particulate filter (DPF). Replace if contaminated.	Exploded View
Stationary Regeneration - Will Not Complete	Current DTCs or high counts of past DTCs	View and troubleshoot the DTCs with CONSULT.	DTC Index
	Stationary (parked) regeneration not allowed to run to completion	Allow the stationary (parked) regeneration to run until completion, which can take up to 2.5 hours.	-
	Exhaust leaks in the exhaust piping leading to the after treatment system or leaks in the after treatment system	Inspect the exhaust piping and the after treatment system for exhaust leaks.	Checking Exhaust System
	After treatment gas temperature sensors are not functioning properly	Monitor the after treatment gas temperature sensor values with CONSULT during the stationary (parked) regeneration.	CONSULT Function
	After treatment system is damaged	Check for progressive damage to the after treatment system.	Exploded View
	Turbocharger malfunctioning	Use CONSULT to perform the "RTCV Hysteresis Test" to verify if the turbocharger nozzle is moving properly. If the "RTCV Hysteresis Test" results in an output of "Fail", replace the turbocharger. If the "RTCV Hysteresis Test" results in an output of "Pass", this indicates that the sector gear movement is acceptable and the actuator should not be removed.	CONSULT Function