Diagnostic Procedure

DTC 51 - Switch Condition Signal

DIAGNOSTIC PROCEDURE
1. CHECK FOR INPUT SIGNAL.
- If OK proceed to DIAGNOSIS BY SYMPTOM.
- If not OK (park / neutral position switch (PNP) failure); see the non-trouble code chart for the park / neutral position switch circuit.
- If not OK (idle switch (IDL) failure); proceed to step 2.
- If not OK (A/C switch failure); proceed to step 3.

2. CHECK RESISTANCE OF THROTTLE POSITION SENSOR.
- If OK check and repair harness or connector between sensor and ECM.
- If not OK adjust or replace throttle position sensor

3. CHECK VOLTAGE OF TERMINAL A/C OF ECM.
- If OK check and replace ECM.
- If not OK check A/C compressor circuit.