Diagnostic Aids

This test is intended to diagnose the following:

• TP sensor.
• Wiring harness circuits (PWR GND, SIG RTN, TP, VPWR and VREF).
• Powertrain Control Module (PCM).

Normal range of throttle angle measurement for TP sensor is 0-85 degrees. To pass quick test procedure, range of throttle rotation (in degrees) must be within 3 percent of specification.

To prevent replacement of good components, be aware, the following non-EEC related areas may be at fault:

• Idle speed.
• Binding throttle shaft or linkage.
• TP sensor not seated.

1. Verify KOER Self-Test Completion
   
   Start engine and allow to idle. Using scan tool, enter KOER self test. If DTC P0121 is present or KOER cannot be terminated, go to next step. If DTC is not present, problem is intermittent and cannot be identified at this time.
2. Check For Intermittent Code
   
   With engine idling, place gear selector in Drive or Reverse. If KOER self-test terminates, go to next step. If KOER self-test does not terminate, turn ignition off and wait for 15 seconds. Start engine and allow to idle. Enter KOER self-test. If DTC P0121 is present or KOER self-test cannot be terminated, go to next step. If DTC is not present, problem is intermittent and cannot be identified at this time.
3. Check Circuit Continuity
   
   Turn ignition off. Check continuity in TP circuit between TP sensor connector and PCM connector terminal No. 89. Check continuity in SIG RTN circuit between TP sensor connector and PCM connector terminal No. 91. If continuity is present, replace TP sensor and repeat QUICK TEST. See TESTS W/CODES - INTRODUCTION article. If continuity is not present, repair open circuit and repeat QUICK TEST.