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Home >> Jeep >> 2021 >> Cherokee Altitude, FWD >> Repair and Diagnosis >> Engine Performance >> System >> 2.4L - DTCS P0602 To P1047 >> DTC Troubleshooting >> P062A-Fuel Pump Control Performance >> Diagnostic Test
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Diagnostic Test

  1. CHECK FOR AN ACTIVE DTC 
    1. With the scan tool, read DTCs and record on the repair order.
    2. Record the Freeze Frame Data and Environmental Data.
    3. With the scan tool, erase DTCs.
    4. Using the recorded Freeze Frame and Environmental Data, along with the When Monitored Conditions above, operate the vehicle in the conditions that set the DTC.
    5. With the scan tool, read DTCs.

      Did the DTC return?

      Yes 

      • Go To  2

      No 

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

      Are there any Fuel Rail Pressure (FRP) Sensor or Fuel Pump Control Module (FPCM) DTCs present?

      Yes 

      No 

      • Go To  3
  3. CHECK THE FUEL SYSTEM FOR LEAKS 
    1. Visually inspect the fuel system for signs of a fuel leak.

      Were any fuel leaks found in the system?

      Yes 

      • Repair the fuel leak in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

      • Go To  4
  4. CHECK THE FUEL DELIVERY SYSTEM 
    1. Perform the CHECKING THE FUEL DELIVERY SYSTEM (HARD START) test procedure to check system for proper fuel pressure. Refer to CHECKING THE FUEL DELIVERY SYSTEM (HARD START) .
    2. During the fuel system pressure test, monitor the FRP Sensor reading on the scan tool.
    3. Compare the FRP Sensor scan tool reading to the actual fuel pressure reading on the fuel pressure gauge.

      Choose below what best matches your findings:

      Actual fuel pressure was below specification: 

      • Perform the appropriate repair to the Fuel Delivery System.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      Actual fuel pressure is above specification and the FRP Sensor reading matches the fuel pressure gauge: 

      • Go To  5

      Actual fuel pressure is at or above specification and the FRP Sensor reading does not match the fuel pressure gauge: 

      • Go To  6
  5. REPLACE THE FUEL PUMP ASSEMBLY AND RETEST FOR DTC 
    NOTE:

    The P062A DTC will occur if the fuel pressure is too high or too low in the system. The Fuel Pump Assembly can be failing and still produce high fuel pressure in the system when the FPCM is defaulted to 80% duty cycle. Therefore, if this DTC is not accompanied by another fuel control system DTC, and the Fuel Rail Pressure Sensor is reading correctly, the Fuel Pump Assembly is the most likely cause of this DTC.

    1. Turn the ignition off.
    2. Replace the Fuel Pump Assembly in accordance with the Service Information. Refer to MODULE, FUEL PUMP, REMOVAL .
    3. Turn the ignition on.
    4. With the scan tool, erase DTCs.
    5. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.

      Did the DTC return?

      Yes 

      • Replace the Fuel Pump Control Module in accordance with the Service Information.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .

      No 

  6. CHECK THE (K181) FUEL PRESSURE SIGNAL CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Turn the ignition off.
    2. Disconnect the Fuel Rail Pressure (FRP) Sensor harness connector.
    3. Disconnect both PCM C1 and C2 harness connectors.
      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.

    4. Connect the (special tool #10436, Adapter, GPEC Diagnostic) to the appropriate PCM harness connector.
    5. Measure the resistance of the (K181) Fuel Pressure Signal circuit between the Fuel Rail Pressure Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  7

      No 

      • Repair the (K181) Fuel Pressure Signal circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  7. CHECK THE (K900) SENSOR GROUND CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (K900) Sensor Ground circuit between the Fuel Pressure Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  8

      No 

      • Repair the (K900) Sensor Ground circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  8. CHECK THE (F856) 5-VOLT SUPPLY CIRCUIT FOR AN OPEN/HIGH RESISTANCE 
    1. Measure the resistance of the (F856) 5-Volt Supply circuit between the Fuel Rail Pressure Sensor harness connector and the GPEC Adaptor.

      Is the resistance below 3.0 Ohms?

      Yes 

      • Go To  9

      No 

      • Repair the (F856) 5-Volt Supply circuit for an open or high resistance.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  9. REPLACE THE FUEL RAIL PRESSURE SENSOR AND RETEST FOR DTC 
    1. Turn the ignition off.
    2. Replace the Fuel Rail Pressure (FRP) Sensor in accordance with the Service Information. Refer to MODULE, FUEL PUMP, REMOVAL .
    3. Connect the Fuel Rail Pressure Sensor and PCM harness connectors.
    4. Turn the ignition on.
    5. With the scan tool, erase DTCs.
    6. Using the When Monitored and Set Conditions above and recorded data, operate the vehicle in the conditions that set the DTC.

      Did the DTC return?

      Yes 

      • Go To  10

      No 

      • Replacing the Fuel Rail Pressure Sensor repaired the fault.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to POWERTRAIN VERIFICATION TEST .
  10. CHECK RELATED PCM AND COMPONENT CONNECTIONS 
    1. Perform any Service Bulletins that apply.
    2. Disconnect all PCM harness connectors.
    3. Disconnect all related in-line harness connections (if equipped).
    4. Disconnect the related component harness connectors.
    5. 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.

    6. Reconnect all PCM harness connectors. Be certain that all harness connectors are fully seated and the connector locks are fully engaged.
    7. Reconnect all in-line harness connectors (if equipped). Be certain that all connectors are fully seated and the connector locks are fully engaged.
    8. Reconnect all related component harness connectors. Be certain that all connectors are fully seated and the connector locks are fully engaged.
    9. With the scan tool, erase DTCs.
    10. Test drive or operate the vehicle in accordance with the when monitored and set conditions.
    11. 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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