Description and Diagnostic Procedure

SYSTEM: Park / Neutral Position Switch Circuit





CIRCUIT DESCRIPTION
The Park/Neutral Position Switch goes on when the shift lever is in the N or P shift position. When it goes on the terminal NSW of the Engine Control Module is grounded to body ground via the starter relay and Theft Deterrent Electronic Control Unit, thus the terminal NSW voltage becomes 0 volts. When the shift lever is in the D, 2, L or R position, the Park/Neutral Position Switch goes off, so the voltage of Engine Control Module terminal NSW becomes positive battery voltage, the voltage of the Engine Control Module internal power source.
If the shift lever is moved from the N position to the D position, this signal is used for air-fuel ratio correction and for idle speed control (estimated control), etc.
When the Park/Neutral Position Switch is off, code "51" is output in the test mode diagnosis. (This is not abnormal.)

NOTE: This diagnosis chart is based on premise that the engine is cranked normally. If the engine is not cranked, proceed to DIAGNOSIS BY SYMPTOM.

1. Check output condition of diagnostic trouble code 51.





- If OK proceed to DIAGNOSIS BY SYMPTOM.
- If not OK type I proceed to step 2.
- If not OK type II proceed to step 3.
2. Check for open in harness and connector switch between Park / Neutral Position Switch and Engine Control Module.
- If OK check and replace Engine Control Module.
- If not OK repair or replace harness or connector.
3. Check Park / Neutral Position Switch.
- If OK check and replace Engine Control Module.
- If not OK replace Park / Neutral Position Switch.