Diagnostic Procedure

DTC 51 - Switch Condition Signal

DIAGNOSTIC PROCEDURE
1. Check for input signal.
- If OK proceed to next circuit on the diagnostic matrix chart under Diagnosis by Symptom.
Testing and Inspection
- If not OK:
- PNP signal - go to Park/Neutral Position Switch Diagnostic Chart.
Park/Neutral Position Switch Circuit
- A/C signal - proceed to step 3.
- IDL signal - proceed to step 2.

2. Check resistance of throttle position sensor.
- If OK check and repair harness or connector between sensor and engine control module (ECM).
- If not OK Adjust or replace throttle position sensor.

3. Check input circuit of A/C.
- If OK proceed to step 4.
- If not OK check and replace A/C amplifier.

4. Check for open and short in harness and connector between A/C amplifier and ECM.
- If OK check and replace ECM.
- If not OK repair or replace harness or connector.