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Home >> Dodge and Ram >> 2018 >> Durango Pursuit >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 17 (3.6L - DTCS P0117 To P0340) >> DTC Troubleshooting >> P0301-Cylinder 1 Misfire >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different variant/trim than selected.
  1. CHECK FOR AN ACTIVE CONDITION 
    1. Turn the ignition on.
    2. With the scan tool, read and record all DTCs and Freeze Frame information.
    3. Operate the vehicle under conditions recorded in the Freeze Frame information when the DTC was set.
      NOTE:

      When operating the vehicle, note when the misfire condition first occurs. This information could be useful later in this troubleshooting procedure. Keep in mind that during a severe misfire (MIL flashing) the PCM will disable the Fuel Injector of the affected cylinder(s) for a calibrated number of engine revolutions to prevent damage to the Catalytic Converter. This means if the actual fault only occurs at highway speed, the misfire may continue during non-highway conditions until the number of crankshaft revolutions has exceeded the calibrated value and the injector is re-enabled.

    4. With the scan tool, view the Misfire Monitor to see which cylinders are effected.

      Are there excessive misfires shown for this cylinder at this time?

      Yes 

      • Go To  2

      No 

  2. CHECK FOR OTHER DTCS 
    1. Refer to the recorded DTCs.

      Are there any fuel, ignition system component, air handling component, VVT system, or VVL system DTCs active or pending?

      Yes 

      • Perform the applicable diagnostic procedure(s). Refer to DTC INDEX .

      No 

      • Go To  3
  3. CHECK FOR MECHANICAL CONDITIONS THAT COULD CAUSE A MISFIRE 
    1. Visually inspect the engine for any of the following conditions:
      NOTE:

      Each of the following conditions can cause a misfire during most operating conditions with the exception of the out of balance tires or warped brake rotors.

      • Worn serpentine belt. Refer to BELT, SERPENTINE, DIAGNOSIS AND TESTING .
      • Binding or misaligned engine driven accessories: A/C Compressor, P/S Pump, Water pump, etc.
      • Engine vacuum leak in the area of the affected cylinder.
      • Improper mounting of the CKP Sensor.
      • Harmonic Balancer out of balance.
      • Extremely out of balance tires or warped brake rotors.

      Were any of the above conditions present?

      Yes 

      No 

      • Go To  4
  4. CHECK THE FUEL QUALITY 
    1. Check the fuel for the following:

      Were any problems found with the fuel?

      Yes 

      • Replace the fuel and, if necessary, flush and clean the fuel system.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  5
  5. CHECK FOR A CLOGGED OR LEAKING FUEL INJECTOR 
    NOTE:

    A Fuel Injector that is plugged and spraying too little fuel, or fouled and spraying too much fuel, will generally cause a misfire during any operating condition. One faulty Fuel Injector will usually cause a single cylinder misfire. However if the injector is spraying an excessive amount of fuel, the excess fuel could also affect the adjoining cylinders. In most cases there will be far more misfire counts on the cylinder with the faulty Fuel Injector than on the other affected cylinders.

    WARNING:

    The fuel system is under a constant pressure (even with the engine off). Before testing or servicing any fuel system hose, fitting or line, the fuel system pressure must be released. Failure to follow these instructions can result in possible serious or fatal injury.

    1. Install the Fuel Pressure Decay Tester (special tool #8978A, Decay Tool, Fuel) to the fuel rail.
    2. Turn the ignition on and allow the fuel pressure to reach maximum pressure and stabilize.
      NOTE:

      The ignition may need to be cycled off and on a couple times to reach maximum fuel pressure in the rail.

    3. Once the pressure reading has stabilized, record the fuel pressure. This is known as the "starting pressure".
    4. With the scan tool, actuate the Fuel Injector for the cylinder that indicated the misfire while monitoring the fuel pressure gauge.
    5. Record the fuel pressure. This is known as the "ending pressure."
      CAUTION:

      After each Fuel Injector actuation, start the engine to clean the cylinder of fuel. Failure to do so could cause engine damage.

    6. Repeat sub-steps two through six with several other Fuel Injectors on cylinders that do not have a misfire. Make sure to start the Fuel Injector actuation at the same starting pressure for each injector. Compare the ending pressures of the known good cylinders to the cylinder with the misfire condition.

      Are the ending pressures about the same for all of the tested injectors?

      Yes 

      • Go To  6

      No, the injector from the cylinder with the misfire stood out from the rest. 

      • If the pressure drop is too small, check for debris in the Fuel Rail or Fuel Injector and repair as necessary. If the pressure drop is too large, suspect a faulty or fouled Fuel Injector as the issue.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  6. CHECK THE IGNITION SYSTEM OPERATION 
    1. Turn the ignition off and remove the Fuel Pressure Decay Tester and connect the fuel lines before continuing.
      NOTE:

      A faulty Ignition Coil or Spark Plug can cause a misfire at idle but could also misfire only under a heavy load on the engine. One faulty Ignition Coil or Spark Plug will usually cause a single cylinder misfire.

    2. Remove the Ignition Coil from the cylinder that is misfiring.
    3. Connect the Ignition Coil harness connector.
    4. Disconnect the Fuel Injector harness connector of the cylinder being tested.
    5. Install a spark tester on the Ignition Coil.
    6. While cranking the engine observe the spark coming from the spark tester.

      Is a crisp blue spark present?

      Yes 

      • Go To  7

      No 

      • Go To  12
  7. INSPECT THE SPARK PLUG 
    1. Turn the ignition off.
    2. Remove the Spark Plug in accordance with the Service Information. Refer to SPARK PLUG, REMOVAL .
    3. Inspect the Spark Plug for the following conditions:
      • Cracks
      • Carbon Tracking
      • Fouling due to oil, coolant or excess fuel in the cylinder
      • Gap size out of specifications
      • Loose or broken electrode
        • Lightly tap the bottom of the spark plug on a solid surface. The electrode in the spark plug should not move.

      Were any of the above conditions present?

      Yes 

      • Replace the Spark Plug in accordance with the Service Information. If the Spark Plug was fouled due to oil, coolant or fuel, diagnose and repair the cause of the fouled plugged.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  8
  8. PERFORM A CYLINDER COMPRESSION TEST 
    NOTE:

    A cylinder compression or valvetrain issue will cause a misfire during all operating conditions. These types of failures will normally affect a single cylinder. However, depending on the type of failure incurred, other cylinders can also be affected and show misfires. In most cases there will be far more misfire counts on the cylinder with the issue than on the other affected cylinders.

    1. Perform a cylinder compression test in accordance with the Service Information on the cylinder with the misfire. Refer to CYLINDER COMPRESSION TEST .

      Is the cylinder compression within specification?

      Yes 

      • Go To  9

      No 

  9. CHECK THE SPARK PLUG OPERATION 
    1. Exchange the Spark Plug with a known good cylinder that was not indicating a misfire or replace the Spark Plug if it is difficult to access.
    2. Start the engine and monitor the misfire monitor screen.

      Did the misfire switch to the previously good cylinder or go away if the Spark Plug was replaced?

      Yes 

      • Repair is complete if Spark Plug was replaced and misfire is gone or replace the Spark Plug if it moved to the known good cylinder.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  10
  10. CLEAN THE CARBON FROM THE COMBUSTION CHAMBERS AND VALVES 
    NOTE:

    Carbon build up on the engine valves and guides can cause a misfire during all operating conditions but is usually more noticeable during cruising speeds or heavy engine load conditions. If carbon build up is becoming an issue it could set only a single cylinder misfire but usually will affect more than one cylinder and set multiple cylinder misfire as well.

    1. Using Mopar Combustion cleaner, de-carbon the engine.
    2. After driving and clearing the combustion cleaner from the engine, erase DTCs with the scan tool.
    3. Test drive the vehicle in accordance with the Freeze Frame data.
    4. With the scan tool, view the Misfire Monitor.

      Did the misfire return?

      Yes 

      • Go To  11

      No 

  11. CHECK THE VVL SYSTEM 
    NOTE:

    The VVL system can set a single cylinder misfire or multiple cylinder misfire depending on the failure. One or more Rocker Arms Stuck in High Lift Mode will cause a misfire at idle and will usually be accompanied with a VVL system DTC. One Rocker Arm stuck in Low Lift Mode will cause a misfire, but only at or above approximately 5000 rpm and will likely not set a VVL system DTC. Two Rocker Arms stuck in Low Lift Mode can cause a misfire at idle or any other engine speed during normal operation.

    1. If the misfired occurred when the engine speed exceeded 5000 rpm and you suspect that the VVL system is causing the misfire, check the operation of the system as follows:
      • The front VVL Solenoid on bank one controls the operation of the Rocker Arms for cylinder one. When the solenoid is off (no oil flow to the Rocker Arms) it should be in high lift mode. If the misfire only occurs when the engine speed is above 5000 rpm, the cause may be due to one Rocker Arm that is stuck in Low Lift Mode for cylinder one. Before checking the Rocker Arms, ensure that the O-rings on the solenoid are not missing or damaged, or that the solenoid is not leaking when off. This can also cause the Rocker Arms to be stuck in Low Lift Mode at higher engine speeds when the oil pressure increases and cause a misfire.

      Were any issues present with the VVL system?

      Yes 

      • Perform the appropriate VVL repair in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  16
  12. CHECK THE (F342) ASD RELAY OUTPUT CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the Ignition Coil harness connector.
    3. Turn the ignition on.
    4. With a scan tool, actuate the ASD Relay.
    5. Using a 12-volt test light connected to ground, probe the (F342) ASD Relay Output circuit at the Ignition Coil harness connector.

      Does the test light illuminate brightly?

      Yes 

      • Go To  13

      No 

      • Stop all scan tool actuations and repair the open or short to ground in the (F342) ASD Relay Output circuit between the PDC and Ignition Coil harness connector.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  13. CHECK THE IGNITION COIL CONTROL CIRCUIT 
    WARNING:

    When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    1. Using a 12-volt test light connected to a 12 volt source, back probe the Coil Control circuit at the Ignition Coil harness connector.
    2. Crank the engine for 5 seconds while observing the test light.

      What was the condition of the test light while cranking the engine?

      Blinking brightly 

      • Replace the Ignition Coil in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      ON constantly 

      • Go To  14

      OFF constantly 

      • Go To  15
  14. CHECK THE COIL CONTROL 1 CIRCUIT FOR A SHORT TO GROUND 
    1. Turn the ignition off.
    2. Disconnect the PCM C2 harness connector.
      CAUTION:

      Do not probe the PCM harness connectors. Probing the PCM harness connectors will damage the PCM terminals resulting in poor terminal to pin connection. Install the GPEC Diagnostic Adaptor to perform the diagnosis.

    3. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the engine harness side of the PCM C2 harness connector. Do not connect the GPEC Diagnostic Adaptor to the PCM.
    4. Check for continuity between ground and the Coil Control 1 circuit at the Ignition Coil harness connector.

      Is there continuity between ground and the Coil Control 1 circuit?

      Yes 

      • Repair the Coil Control 1 circuit for a short to ground.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  16
  15. CHECK THE COIL CONTROL 1 CIRCUIT FOR AN OPEN 
    1. Turn the ignition off.
    2. Measure the resistance of the Coil Control 1 circuit between the Ignition Coil harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  16

      No 

      • Repair the Coil Control 1 circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  16. CHECK RELATED HARNESS CONNECTIONS 
    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.
      • Check for spread terminals and verify proper terminal tension.

      Repair any conditions that are found.

    5. Connect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    6. Connect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    7. Connect 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. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    10. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      No 

      • The wiring or poor connection problem has been repaired.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
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