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Home >> Jeep >> 2005 >> Wrangler X, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 628 (Powertrain Diagnostic Procedures - DRIVEABILITY - NGC Symptoms & Diagnostic Tests (DTCS P0016 To P0563)) >> DRIVEABILITY - NGC - Diagnostic Tests >> P0123-Throttle Position Sensor No. 1 High (5.7L) (Gas - NGC) >> Diagnostics Procedures

Diagnostics Procedures

WARNING: This page is about a different car, the 2004 Dodge Pickup and 2004 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
NOTE: Refer to VERIFICATION TESTS for appropriate verification test procedures.
    NOTE: If P2101 is also set with P0123, make sure the throttle blade moves freely and does not hang up near WOT by performing the Pedal Follower test with the scan tool.
    NOTE: If P0642 or P0643 are set along with P0123, diagnose the 5-volt supply DTCs before continuing.
  1. Start the engine.

    With the DRBIII®, read the TP Sensor voltage.

    Is the voltage above 4.47 volts?

    1. Yes --> Go To 2
    2. No --> Go To 8
  2. Turn the ignition off.

    Disconnect the Throttle Body Assembly harness connector.

    Ignition on, engine not running.

    Connect a jumper wire between the (K22) TP Sensor No. 1 Signal circuit and the (K922) TP Sensor Return circuit in the Throttle Body harness connector.

    With the DRBIII®, monitor the TP Sensor No. 1 voltage.

    Is the voltage below 0.5 volt?

    1. Yes --> Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, with the DRBIII® under the Misc. Menu select ETC RELEARN.

      Perform POWERTRAIN VERIFICATION TEST VER - 5 .

    2. No --> Go To 3
    NOTE: Remove the jumper wire before continuing.
  3. Turn the ignition off.

    Disconnect the PCM harness connectors.

    Ignition on, engine not running.

    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.

    Using a 12-volt test light connected to ground, probe the (K22) TP Sensor No. 1 Signal circuit at the appropriate terminal of special tool #8815.

    Does the test light illuminate brightly?

    1. Yes --> Repair the short to voltage in the (K22) TP Sensor No. 1 Signal circuit.

      Perform POWERTRAIN VERIFICATION TEST VER - 5 .

    2. No --> Go To 4
  4. Turn the ignition off.
    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 (K22) TP Sensor No. 1 Signal circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5 ohms?

    1. Yes --> Go To 5
    2. No --> Repair the open in the (K22) TP Sensor No. 1 Signal circuit.

      Perform POWERTRAIN VERIFICATION TEST VER - 5 .

  5. Measure the resistance between the (K22) TP Sensor No. 1 Signal circuit and the (F855) 5-volt Supply circuit between the appropriate terminals of special tool #8815.

    Is the resistance below 100 ohms?

    1. Yes --> Repair the short between the (K22) TP Sensor No. 1 Signal circuit and the (F855) 5-volt Supply circuit.

      Perform POWERTRAIN VERIFICATION TEST VER - 5 .

    2. No --> Go To 6
    6. 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.
  6. Measure the resistance of the (K922) Sensor Return circuit from the Throttle Body harness connector to the appropriate terminal of special tool #8815.

    Is the resistance below 5.0 ohms?

    1. Yes --> Go To 7
    2. No --> Repair the open in the (K922) Sensor Return circuit.

      Perform POWERTRAIN VERIFICATION TEST VER - 5 .

    7. NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.
  7. Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

    If there are no possible causes remaining, view repair.

    1. Repair
      1. Replace and program the Powertrain Control Module per Service Information.

        Perform POWERTRAIN VERIFICATION TEST VER - 5 .

  8. With the DRBIII®, perform the Throttle Follower Test.

    Monitor the TP Sensor No. 1 voltage while slowly pressing the Throttle pedal down.

    Is there a smooth voltage change from low to high?

    1. Yes --> Refer to the SYMPTOM: INTERMITTENT CONDITION  Symptom (Diagnostic Procedure).

      Perform POWERTRAIN VERIFICATION TEST VER - 5 .

    2. No --> Disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. After installation is complete, with the DRBIII® under the Misc. Menu select ETC RELEARN.

      Perform POWERTRAIN VERIFICATION TEST VER - 5 .

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