Circuit Description and Diagnostic Chart

SYSTEM: Park/Neutral Position Switch Circuit (Only vehicles with A/T)

WIRING DIAGRAM





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 (ECM) is grounded to body ground via the starter relay and theft deterrent ECM, thus the terminal NSW voltage becomes 0V. When the shift lever is in the D, 2, L or R position, the park/neutral position switch goes off, so the voltage of ECM terminal NSW becomes battery positive voltage, the voltage of the ECM 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.)

DIAGNOSTIC PROCEDURE
HINT: This diagnosis chart is based on the premise that the engine cranks normally. If the engine does not crank, proceed to Diagnosis By Symptom in "Powertrain Management".
1. Check output condition of diagnostic trouble code 51
^ If OK, proceed to next circuit inspection shown on the matrix chart (Diagnosis By Symptom).
Testing and Inspection
^ If not OK Type I, proceed to Step 2.
^ If not OK Type II, Check and replace ECM.
NOTE: For an explanation of Type I and Type II failure, refer to Inspection Procedure.
Inspection Procedure
2. Check for open in harness and connector between park/neutral position switch and ECM.
^ If OK, check and replace ECM.
^ If not OK, repair or replace harness or connector.
3. Check park/neutral position switch.
^ If OK, check and replace ECM.
^ If not OK, replace park/neutral position switch.