Diagnostic Test

WARNING: This page is about a different car, the 2019 RAM 3500 HD and 2019 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

CHECK MODULE SOFTWARE UPDATE
NOTE:
There is a new Selective Catalytic Reduction (SCR) Catalyst available in STAR Parts now. This SCR Catalyst is different from the one originally installed in 2013-2015 6.7L Trucks. The new SCR Catalyst does not include the Ammonia (NH3) Sensor.

NOTE:
There are two different module software updates related to these two different SCR Catalysts. One is called a 'two-sensor update'. The other is called a 'three-sensor update'. The three-sensor update includes both NOx Sensors and the Ammonia Sensor. The two-sensor update applies when the Ammonia Sensor is no longer present.

NOTE:
Check the repair history of this vehicle to see if there was a recent Aftertreatment repair made. Pay particular attention to the possible replacement of the SCR Catalyst. If the Catalyst was recently replaced, it probably does not have an Ammonia (NH3) Sensor.
1. Ignition off.
2. Inspect the SCR Catalyst for the presence of an Ammonia Sensor probe (near the center of the Catalyst).
  NOTE:
  If there is an Ammonia Sensor probe present in the center of the SCR Catalyst, the PCM should have the three-sensor module software update.
  
  NOTE:
  If there is no Ammonia Sensor probe present in the center of the SCR Catalyst, the PCM should have the two-sensor module software update.
  
  Did the visual inspection of the SCR Catalyst match the module software update seen on the scan tool?
  
  Yes
  - Go To 2
  No
  - Perform the module software update that matches the type of SCR Catalyst in the vehicle.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK FOR ACTIVE DTC
1. Ignition on, engine not running.
2. With the scan tool, read DTCs.
  Is the DTC Active?
  
  Yes
  - Go To 3
  No
  - Perform the INTERMITTENT CONDITION diagnostic procedure. Refer to INTERMITTENT CONDITION .
CHECK FOR OTHER DTCS
NOTE:
Repair any Voltage Low DTCs before proceeding with this test procedure.

NOTE:
The J1939 Datalink is a BUS circuit which the PCM uses to communicate with the Ammonia (NH3) Sensor, Turbo Actuator, DEF Dosing Control Unit, NOx Sensor 1/1, and NOx Sensor 1/2. The Turbo Actuator and NOx Sensor 1/1 are located on their own network in the engine harness. The Ammonia Sensor, DEF Dosing Control Unit, and NOx Sensor 1/2 are located on a separate network in the vehicle harness. If the J1939 Datalink in the engine harness is shorted, communication lost DTC's will be set against the Turbo Actuator and NOx Sensor 1/1. If the J1939 Datalink in the vehicle harness is shorted, communication lost DTCs will be set against the Ammonia Sensor, DEF Dosing Control Unit, and NOx Sensor 1/2. The Ammonia Sensor, NOx Sensor 1/1, and NOx Sensor 1/2 share the same fused battery supply circuit in the PDC. All 3 sensors will lose communication and set DTCs if the fuse is blown. The Turbo Actuator and the DEF Dosing Control Unit have their own separate fused battery circuits in the PDC.

Are there lost communication DTCs present against ALL the components (Ammonia Sensor, NOx Sensor 1/2, DEF Dosing Control Unit) in the vehicle harness?

Yes
- Go To 7
No
- Go To 4
CHECK SYSTEM VOLTAGE
1. Check the Batteries and charging system for proper system voltage and operation.
  Is the system voltage normal?
  
  Yes
  - Go To 5
  No
  - Diagnose and repair the Batteries and charging system before continuing.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE AMMONIA SENSOR MODULE POWER AND GROUND CIRCUITS
1. Turn the ignition on, engine not running.
2. Disconnect the Ammonia Sensor Module C1 harness connector.
3. Measure the voltage across the (F204) Fused Ignition Switch circuit and the (Z915) Ground circuit at the Ammonia Sensor Module C1 harness connector.
  NOTE:
  Measure the voltage at key on, engine cranking, and at idle.
  
  Does the voltage read within 1.0 volt of battery voltage?
  
  Yes
  - Go To 6
  No
  - Repair the (204) Fused Ignition Switch Output circuit for an open or short to ground. If the (204) Fused Ignition Switch Output circuit checks good, repair the (Z915) Ground circuit for an open.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE J1939 DATALINK OPEN
1. Turn the ignition off.
2. Disconnect the DEF NOx Sensor 1/2 harness connector.
3. Disconnect the PCM C2 harness connector.
4. Disconnect the DEF Dosing Control Unit C1 harness connector.
  NOTE:
  Check connectors - Clean/repair as necessary.
5. Measure the resistance of the J1939 Datalink (+) circuit between the Ammonia Sensor Module C1 harness connector and the PCM C2 harness connector.
6. Measure the resistance of the J1939 Datalink (-) circuit between the Ammonia Sensor Module C1 harness connector and the PCM C2 harness connector.
  Is the resistance below 5.0 Ohms for both circuits?
  
  Yes
  - Replace the Ammonia Sensor Module in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Repair the J1939 Datalink circuit that measured above 5.0 Ohms for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE COMPONENTS ON THE J1939 DATALINK
NOTE:
Disconnect only one component at a time during this next step. If the DTCs for the components that are STILL CONNECTED change from active to stored, the component that was disconnected is faulty. If all of the DTCs remain active, then the disconnected component is not the problem. Reconnect each component before going on to the next one so that only one component is disconnected at a time.
1. Turn the ignition off.
2. Disconnect the Ammonia Sensor Module C1 harness connector. Cycle the ignition key on and off three times ending with the ignition on. Leave the ignition in the off position for 75 seconds each time.
  NOTE:
  Monitor the status of the DTCs for the remaining connected components with the scan tool.
3. Turn the ignition off and reconnect the Ammonia Sensor Module C1 harness connector.
4. Disconnect the NOx Sensor Module 1/2 harness connector. Cycle the ignition key on and off three times ending with the ignition on. Leave the ignition in the off position for 75 seconds each time.
  NOTE:
  Monitor the status of the DTCs for the remaining connected components with the scan tool.
5. Turn the ignition off and reconnect the NOx Sensor Module 1/2 harness connector.
6. Disconnect the DEF Dosing Control Unit C1 harness connector. Cycle the ignition key on and off three times ending with the ignition on. Leave the ignition in the off position for 75 seconds each time.
  NOTE:
  Monitor the status of the DTCs for the remaining connected components with the scan tool.
  
  Did the status of the DTCs change to stored for the components STILL CONNECTED when disconnecting any one of the components listed above?
  
  Yes
  - Replace the component that caused the DTC change from active to stored in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Go To 8
CHECK THE J1939 DATALINK FOR A SHORT TO GROUND
1. Turn the ignition off.
2. Disconnect the NOx Sensor 1/2 Module, DEF Dosing Control Unit C1, Ammonia Sensor Module C1 and the PCM C2 harness connectors.
3. Measure the resistance between ground and the J1939 Datalink (+) circuit at the PCM C2 harness connector.
4. Measure the resistance between ground and the J1939 Datalink (-) circuit at the PCM C2 harness connector.
  Is the resistance above 10k Ohms for both circuits?
  
  Yes
  - Go To 9
  No
  - Repair the J1939 Datalink circuit that did not measure above 10k Ohms for a short to ground.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE J1939 DATALINK FOR A SHORT
1. Measure the resistance between the J1939 Datalink (+) circuit at the PCM C2 harness connector and all other circuits in the PCM C2 harness connector.
2. Measure the resistance between the J1939 Datalink (-) circuit at the PCM C2 harness connector and all other circuits in the PCM C2 harness connector.
  NOTE:
  Disregard any resistance between 50 and 70 Ohms between the J1939 (+) and the J1939 Datalink (-) pins.
  
  Is the resistance above 10k Ohms for both measurements?
  
  Yes
  - Go To 10
  No
  - Repair the J1939 Datalink circuit for a short to the circuit that did not measure above 10k Ohms.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
CHECK THE J1939 DATALINK CIRCUITS FOR AN OPEN/HIGH RESISTANCE
1. Measure the resistance of the J1939 Datalink (+) circuit between the Ammonia Sensor Module C1 harness connector and the PCM C2 harness connector.
2. Measure the resistance of the J1939 Datalink (-) circuit between the Ammonia Sensor Module C1 harness connector and the PCM C2 harness connector.
  Is the resistance below 5.0 Ohms for both circuits?
  
  Yes
  - Go To 11
  No
  - Repair the J1939 circuit for an open or high resistance.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
POWERTRAIN CONTROL MODULE
1. Disconnect all PCM harness connectors.
2. Disconnect all related in-line harness connections (if equipped).
3. Disconnect the related component harness connectors.
4. Inspect harness connectors, component connectors, and all male and female terminals for the following conditions:
  - Proper connector installation.
  - Damaged connector locks.
  - Corrosion.
  - Other signs of water intrusion.
  - Weather seal damage (if equipped).
  - Bent terminals.
  - Overheating due to a poor connection (terminal may be discolored due to excessive current draw).
  - Terminals that have been pushed back into the connector cavity.
  - Perform a terminal drag test on each connector terminal to verify proper terminal tension.
  Repair any conditions that are found.
5. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
6. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
7. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
8. With the scan tool, erase DTCs.
9. Using the recorded Freeze Frame and Environmental Data, along with the When Monitored and Set Conditions above, operate the vehicle in the conditions that set the DTC.
10. With the scan tool, read PCM DTCs.
  Did the DTC return?
  
  Yes
  - Replace the Powertrain Control Module (PCM) in accordance with the Service Information.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  No
  - Test complete.
  - Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .