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Home >> Jeep >> 2008 >> Wrangler Rubicon, Standard >> Repair and Diagnosis >> Engine Performance >> System >> DTCS P0016 To P0125, Pre-Diagnostic Troubleshooting Procedure, Intermittent Condition >> P0121-Throttle Position Sensor 1 Performance >> Diagnostic Test

Diagnostic Test

  1. ACTIVE DTC 
    NOTE: When this DTC is Active the engine speed, torque, and vehicle speed are limited to a Limp in mode.
    NOTE: Diagnose any other TP Sensor DTC(s) before continuing.
    NOTE: The throttle plate should be free from binding and carbon build up.
    NOTE: Make sure the throttle plate is at the idle position.
    NOTE: Inspect the engine for vacuum leaks.

    Start the engine an allow the engine to idle.

    With a scan tool, select View DTCs.

    Is the DTC Active at this time? 

    Yes 

    1. Go To  2.

    No 

    1. Go To  9.
  2. EXCESSIVE RESISTANCE IN THE (K22) TP SIGNAL 1 CIRCUIT 

    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 along with the #8815-1 to perform the diagnosis.

    Using a voltmeter perform a voltage drop test. Backprobe the (K22) TP Signal 1 circuit at the Throttle Body harness connector and to probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.

    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.

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

    Monitor the voltmeter.

    Is the voltage below 0.5 of a volt? 

    Yes 

    1. Go To  3.

    No 

    1. Repair the excessive resistance in the (K22) TP Signal 1 circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  3. EXCESSIVE RESISTANCE IN THE (K122) TP SIGNAL 2 CIRCUIT 

    Turn the ignition off.

    Move the voltmeter leads to backprobe the (K122) TP Signal 2 circuit at the Throttle Body harness connector and to probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.

    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.

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

    Monitor the voltmeter.

    Is the voltage below 0.5 of a volt? 

    Yes 

    1. Go To  4.

    No 

    1. Repair the excessive resistance in the (K122) TP Signal 2 circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  4. EXCESSIVE RESISTANCE IN THE (F855) 5-VOLT SUPPLY CIRCUIT 

    Turn the ignition off.

    Move the voltmeter leads to backprobe the (F855) 5-volt Supply circuit at the Throttle Body harness connector and to probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.

    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.

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

    Monitor the voltmeter.

    Is the voltage below 0.5 of a volt? 

    Yes 

    1. Go To  5.

    No 

    1. Repair the excessive resistance in the (F855) 5-volt Supply circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  5. EXCESSIVE RESISTANCE IN THE (K922) TP SENSOR GROUND CIRCUIT 

    Turn the ignition off.

    Move the voltmeter leads to backprobe the (K922) TP Sensor Ground circuit at the Throttle Body harness connector and to probe the appropriate terminal of the special tool #8815. Make sure the voltmeter leads are connected so a positive polarity is displayed on the voltmeter.

    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.

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

    Monitor the voltmeter.

    Is the voltage below 0.5 of a volt? 

    Yes 

    1. Go To  6.

    No 

    1. Repair the excessive resistance in the (K922) TP Sensor Ground circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .
  6. (K22) TP SIGNAL 1 CIRCUIT SHORTED TO THE (K122) TP SIGNAL 2 CIRCUIT 
    Fig 1: Measuring Resistance Between TP Sensor No. 1 Signal Circuit & TP Sensor No. 2 Signal Circuit
    GC0056805Courtesy of CHRYSLER LLC

    Turn the ignition off.

    Disconnect the C2 PCM harness connector.

    Disconnect the Throttle Body harness connector.

    Measure the resistance between the (K22) TP Signal 1 circuit and the (K122) TP Signal 2 circuit in the Throttle Body harness connector.

    Is the resistance below 5.0 ohms? 

    Yes 

    1. Repair the short between the (K122) TP Signal 2 circuit and the (K22) TP Signal 1 circuit.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To  7.
  7. THROTTLE POSITION SENSOR 
    Fig 2: View Of Throttle Position Sensor Connector
    GC0056801Courtesy of CHRYSLER LLC
    Fig 3: View Of Throttle Body Connector
    GC0056782Courtesy of CHRYSLER LLC

    Connect the C2 PCM harness connector.

    Ignition on, engine not running.

    With a scan tool, monitor the TP Sensor No.1 and No.2 voltage.

    Connect a jumper wire between the (K922) TP Sensor Ground circuit and the (K22) TP Signal 1 circuit.

    NOTE: TP Sensor No.1 voltage should change from approximately 4.5 volts to less than 0.5 of a volt.

    For TP Sensor No.2, connect a jumper wire between (F855) 5-volt Supply circuit and the (K122) TP Signal 2 circuit.

    NOTE: TP Sensor No.2 voltage should change from approximately 0 volts to 5.0 volts?

    Is the voltage reading within the listed specification when the jumper wire is installed? 

    Yes 

    1. Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. If OK, replace the Throttle Body Assembly. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Go To  8.
      NOTE: Remove the jumper wire before continuing.
  8. POWERTRAIN CONTROL MODULE (PCM) 

    Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body 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 Throttle Body 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 .
  9. THROTTLE FOLLOWER TEST 

    Ignition on, engine not running.

    With a scan tool, perform the ETC Throttle Follower Test and monitor the TP Sensor No.1 or No.2 voltage.

    Slowly press the throttle pedal down.

    The voltage for TP Sensor No.1 should start at approximately 0.7 of a volt and increase to approximately 4.3 volts.

    The voltage for TP Sensor No.2 should start at approximately 4.3 volts and decrease to approximately 0.7 of a volt.

    Is the voltage within the range of the listed specification for the appropriate Sensor? 

    Yes 

    1. Refer to the INTERMITTENT CONDITION  Diagnostic Procedure.
    2. Perform POWERTRAIN VERIFICATION TEST .

    No 

    1. Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. If OK, replace the Throttle Body Assembly. Disconnect the Battery when replacing the Throttle Body Assembly. After installation is complete, use a scan tool and select the ETC RELEARN function.
    2. Perform POWERTRAIN VERIFICATION TEST .
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