Diagnostic Aids

Check for any of the following conditions:

• If a DTC P0122 or P0123 are also set, diagnose those DTCs first.
• A damaged wiring harness - Inspect the wiring harness for damage. If the harness appears to be okay, observe the TP display on the scan tool while moving connectors and wiring harnesses related to the TP sensor. A change in the TP display will indicate the location of the fault.
• A binding or sticking throttle plate may cause a DTC P0121 to set.

If a DTC P0121 is intermittent, driving the vehicle under the following conditions can verify whether the fault is present. Perform the scan tool clear DTC information function. Road test the vehicle while monitoring the DTC P0121 diagnostic on the scan tool under the Not Ran Since Code Cleared selection in the DTC Information menu. If a DTC P0121 appears in the Not Ran Since Code Cleared list, the P0121 diagnostic has not yet run. When the DTC P0121 does not appear in the Not Ran Since Code Cleared list, the P0121 diagnostic has run. If the MIL is NOT ILLUMINATED, and there is no PENDING DTC Status in DTC Information, the P0121 diagnostic has passed. DTCs MUST BE CLEARED in order to view the CURRENT STATUS of the Not Ran Since Code Cleared list. DO NOT FORGET that the Not Ran Since Code Cleared list only indicates that the test has run, not whether the test passed or failed. The DTC Information screen must be checked for CURRENT or PENDING status, in order to determine the outcome of the diagnostic test involved.

An intermittent malfunction may be caused by a fault in the TP sensor electrical circuit. Inspect the wiring harness and components for an intermittent condition. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES - 2.0L & 2.5L TRACKER article.

If the DTC P0121 cannot be duplicated, the information included in the Freeze Frame data can be useful in determining vehicle operating conditions when the DTC was first set.