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Home >> Jeep >> 2007 >> Commander Base, 4.7 P, AWD >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P1602 To P2123 >> P2122-Accelerator Pedal Position Sensor 1 Circuit Low >> Diagnostic Test

Diagnostic Test

  1. 1) ACTIVE DTC 
    NOTE: When this DTC is Active the engine speed, torque, and vehicle speed are limited to a Limp in mode.

    Start the engine and allow it to reach normal operating temperature.

    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 can result in personal injury or death.
    NOTE: Diagnose and repair any system voltage or sensor supply voltage DTCs before continuing with this test.
    NOTE: If you are viewing data recorder information or Freeze Frame data the APP Sensor No. 2 is pulled low by the PCM as part of its system testing. This test happens every 320 milliseconds and may not show up on the scan tool but may show up on a data recorder or lab scope. It is acceptable to see the voltage close to zero with a normal sensor when using a data recorder/lab scope.

    With the scan tool, select View DTCs.

    Is the DTC Active at this time? 

    Yes 

    1. Go to  2).

    No 

    1. Go to  11).
  2. 2) (F855) 5-VOLT SUPPLY CIRCUIT 
    Fig 1: Measuring Voltage On 5-Volt Supply Circuit At APP Sensor Harness Connector
    GC0050977Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the APP Sensor harness connector.

    Ignition on, engine not running.

    Measure the voltage on the (F855) 5-volt Supply circuit in the APP Sensor harness connector.

    Is the voltage between 4.5 and 5.2 volts? 

    Yes 

    1. Go to  3).

    No 

    1. Go to  8).
  3. 3) (K23) APP SENSOR NO. 1 SIGNAL CIRCUIT OPEN 
    Fig 2: Checking APP Sensor No. 1 Signal Circuit For Open
    GC0050978Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the C3 PCM 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 Miller Special Tool #8815 to perform diagnosis.

    Measure the resistance of the (K23) APP Sensor No. 1 Signal circuit from the APP Sensor harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go to  4).

    No 

    1. Repair the open in the (K23) APP Sensor No. 1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  4. 4) (K23) APP SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO GROUND 
    Fig 3: Checking APP Sensor No. 1 Signal Circuit For Short To Ground
    GC0050979Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (K23) APP Sensor No. 1 Signal circuit in the APP Sensor harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (K23) APP Sensor No. 1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  5).
  5. 5) (K23) APP SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO THE (K167) APP SENSOR NO. 1 RETURN CIRCUIT 
    Fig 4: Checking APP Sensor No. 1 Signal Circuit For Short To APP Sensor No. 1 Return Circuit
    GC0050980Courtesy of CHRYSLER LLC

    Measure the resistance between the (K23) APP Sensor No. 1 Signal circuit and the (K167) Sensor No. 1 Return circuit at the APP Sensor harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short between the (K167) APP Sensor No. 1 Return circuit and the (K23) APP Sensor No. 1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  6).
  6. 6) (K23) APP SENSOR NO. 1 SIGNAL CIRCUIT SHORTED TO THE (K400) APP SENSOR NO. 2 RETURN CIRCUIT 
    Fig 5: Measuring Resistance Between APP Signal 1 Circuit And Return 2 Circuit
    GC0050981Courtesy of CHRYSLER LLC

    Measure the resistance between the (K23) APP Sensor No. 1 Signal circuit and the (K400) APP Sensor No. 2 Return circuit in the APP Sensor harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short between the (K400) APP Sensor No. 2 Return circuit and the (K23) APP Sensor No. 1 Signal circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  7).
  7. 7) ACCELERATOR PEDAL POSITION SENSOR 
    Fig 6: Checking Accelerator Pedal Position Sensor
    GC0050982Courtesy of CHRYSLER LLC

    Connect the PCM harness connectors.

    Ignition on, engine not running.

    With a scan tool, monitor the APP Sensor No. 1 voltage.

    Connect a jumper wire between the (F855) 5-volt Supply circuit and the (K23) APP Sensor No. 1 Signal circuit in the Sensor harness connector.

    NOTE: The sensor voltage should be approximately 5.0 volts (plus or minus .1 volt) with the jumper wire installed.

    Does the scan tool display the voltage as described above? 

    Yes 

    1. Verify that there is good pin to terminal contact in the APP Sensor and Powertrain Control Module connectors. If OK, replace the APP Sensor Assembly per Service Information. After installation is complete, use a scan tool and select the ETC RELEARN function to relearn the APPS values.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  10).
      NOTE: Remove the jumper wire before continuing.
  8. 8) (F855) 5-VOLT SUPPLY CIRCUIT OPEN 
    Fig 7: Measuring Resistance Of 5-Volt Supply Circuit
    GC0050983Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the C2 PCM 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 Miller Special Tool #8815 to perform diagnosis.

    Measure the resistance of the (F855) 5-volt Supply circuit from the Sensor harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Go to  9).

    No 

    1. Repair the open in the (F855) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  9. 9) (F855) 5-VOLT SUPPLY CIRCUIT SHORTED TO GROUND 
    Fig 8: Measuring Resistance Between Ground And 5-Volt Supply Circuit
    GC0050984Courtesy of CHRYSLER LLC

    Measure the resistance between ground and the (F855) 5-volt Supply circuit in the APP Sensor harness connector.

    Is the resistance below 100 ohms? 

    Yes 

    1. Repair the short to ground in the (F855) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go to  10).
  10. 10) POWERTRAIN CONTROL MODULE (PCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Accelerator Pedal Position Sensor and the Powertrain Control Module (PCM).

    Look for any chafed, pierced, pinched, or partially broken wires.

    Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the APP Sensor and Powertrain Control Module connectors.

    Refer to any Technical Service Bulletins that may apply.

    Were there any problems found? 

    Yes 

    1. Repair as necessary.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Replace and program the Powertrain Control Module per Service Information.
    2. Perform POWERTRAIN VERIFICATION TEST .
  11. 11) APP SENSOR SWEEP 

    Ignition on, engine not running.

    With a scan tool, monitor the APP Sensor 1 voltage.

    Slowly press the Accelerator pedal down.

    Does voltage start at approximately 0.45 of a volt and go above 4.6 volts with a smooth transition? 

    Yes 

    1. Refer to INTERMITTENT CONDITION Diagnostic Procedure.

    No 

    1. Replace the APP Sensor Assembly per Service Information. After installation is complete, use a scan tool and select the ETC RELEARN function to relearn the APPS values.
    2. Perform POWERTRAIN VERIFICATION TEST .
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