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Home >> Chrysler >> 2011 >> 300 C, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 416 (5.7L CNG - DTCS P000B To P0203 - 2500 Hd) >> Diagnosis And Testing >> P0121-Throttle Position Sensor 1 Performance >> Diagnostic Test

Diagnostic Test

WARNING: This page is about a different car, the 2013 RAM 2500 HD and 2012 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.
  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 TPS Circuit Low or High DTCs before continuing.

    NOTE:

    Make sure the throttle plate is at the idle position.

    NOTE:

    Inspect the engine for vacuum leaks.

    1. Turn the ignition on, engine not running.
    2. With a scan tool, read the active DTCs.

      Is the DTC Active at this time?

      Yes 

      • Go To  2

      No 

      • Go To  5
  2. CHECK FOR EXCESSIVE RESISTANCE IN THE (K22) TPS 1 SIGNAL CIRCUIT 
    1. Turn the ignition off.
    2. Disconnect the Throttle Body Assembly harness connector.
    3. 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.

    4. Connect the (special tool #10436, Adapter, GPEC Diagnostic).
    5. Measure the resistance of the (K22) TPS 1 Signal circuit between the Throttle Body harness connector and the GPEC Adaptor.

      Is the resistance below 5.0 Ohms?

      Yes 

      • Go To  3

      No 

      • Repair the excessive resistance in the (K22) TPS 1 Signal circuit.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .
  3. THROTTLE POSITION SENSOR 
    1. Turn the ignition off.
    2. Reconnect the PCM C2 harness connector.
    3. Turn the ignition on, engine not running.
    4. Using the scan tool, monitor the TPS 1 and TPS 2 voltage.
    5. Connect a jumper between the (K922) TPS Return circuit and the (K22) TPS 1 Signal circuit.
      NOTE:

      TP Sensor No. 1 voltage should change from approximately 4.7 volts to 0 volts.

    6. For TPS 2, connect a jumper between (F855) 5-Volt supply circuit and the (K122) TPS 2 Signal circuit.
      NOTE:

      TPS 2 voltage should change from approximately 0 volts to 5.0 volts.

      Is the voltage reading within the listed specification with the jumper installed?

      Yes 

      • Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. If OK, disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. Refer to THROTTLE BODY, REMOVAL . After installation is complete, using a scan tool, select the ETC RELEARN function.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

      • Go To  4
  4. POWERTRAIN CONTROL MODULE (PCM) 
    1. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Throttle Body and the Powertrain Control Module (PCM).
    2. Look for any chafed, pierced, pinched, or partially broken wires.
    3. 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.
    4. Perform any Technical Service Bulletins that may apply.

      Were there any problems found?

      Yes 

      • Repair as necessary.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .

      No 

  5. THROTTLE FOLLOWER TEST 
    1. Ignition on, engine not running.
    2. Using the scan tool, perform the ETC Throttle Follower Test and monitor the TPS 1 and TPS 2 voltage.
    3. Slowly press the throttle pedal down.
    4. The voltage for TPS 1 voltage should start at approximately 0.7 volts and increase to approximately 4.3 volts.
    5. The voltage for TPS 2 voltage should start at approximately 4.3 volts and decrease to approximately 0.7 volts.

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

      Yes 

      No 

      • Verify that there is good pin to terminal contact in the Throttle Body and Powertrain Control Module connectors. If OK, disconnect the Battery when replacing the Throttle Body Assembly. Replace the Throttle Body Assembly. Refer to THROTTLE BODY, REMOVAL . After installation is complete, using a scan tool select the ETC RELEARN function.
      • Perform the POWERTRAIN VERIFICATION TEST. Refer to STANDARD PROCEDURE .