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DTC P0850

DTC P0850 Neutral switch input circuit problem
DETECTION CONDITION 
  • The PCM monitors the input signal from the neutral switch when the vehicle is running. If the input signal does not change while alternately running more than 30 km/h {19 mph} 8 times  , the PCM determines that there is a neutral switch input circuit malfunction.

Diagnostic support note 
  • This is a continuous monitor (CCM).
  • The MIL illuminates if the PCM detects the above malfunction condition in two consecutive drive cycles or in one drive cycle while the DTC for the same malfunction has been stored in the PCM.
  • PENDING CODE is available if the PCM detects the above malfunction condition during the first drive cycle.
  • FREEZE FRAME DATA (Mode 2/Mode 12) is available.
  • The DTC is stored in the PCM memory.
POSSIBLE CAUSE 
  • Neutral switch connector or terminals malfunction
  • Open circuit in wiring harness between neutral switch terminal B and body ground
  • Short to ground in wiring harness between neutral switch terminal A and PCM terminal 2AS
  • Neutral switch malfunction
  • PCM connector or terminals malfunction
  • Open circuit in wiring harness between neutral switch terminal A and PCM terminal 2AS
  • PCM malfunction
G07878135
DIAGNOSTIC PROCEDURE

STEP INSPECTION ACTION
1 VERIFY FREEZE FRAME DATA (MODE 12) HAS BEEN RECORDED 
  • Has the FREEZE FRAME DATA (Mode 12) been recorded?
 Yes Go to the next step.
No Record the FREEZE FRAME DATA (Mode 12) on the repair order, then go to the next step.
2 VERIFY RELATED REPAIR INFORMATION AVAILABILITY 
  • Verify related Service Bulletins and/or on-line repair information availability.
  • Is any related repair information available?
 Yes Perform repair or diagnosis according to the available repair information.
  • If the vehicle is not repaired, go to the next step.
No Go to the next step.
3 INSPECT NEUTRAL SWITCH CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Disconnect the neutral switch connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the connector and/or terminals, then go to Step 9.
No Go to the next step.
4 INSPECT NEUTRAL SWITCH GROUND CIRCUIT FOR OPEN CIRCUIT 
  • Neutral switch connector is disconnected.
  • Turn the ignition switch off.
  • Inspect for continuity between neutral switch terminal B (wiring harness-side) and body ground.
  • Is there continuity?
 Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to Step 9.
5 INSPECT NEUTRAL SWITCH SIGNAL CIRCUIT FOR SHORT TO GROUND 
  • Neutral switch connector is disconnected.
  • Turn the ignition switch off.
  • Inspect for continuity between neutral switch terminal A (wiring harness-side) and body ground.
  • Is there continuity?
 Yes If the short to ground circuit could be detected:
  • Repair or replace the wiring harness for a possible short to ground.

If the short to ground circuit could not be detected:
Go to Step 9.
No Go to the next step.
6 INSPECT NEUTRAL SWITCH 
 Yes Replace the neutral switch, then go to Step 9.
(See NEUTRAL SWITCH REMOVAL/INSTALLATION ).
No Go to the next step.
7 INSPECT PCM CONNECTOR FOR POOR CONNECTION 
  • Turn the ignition switch off.
  • Disconnect the PCM connector.
  • Inspect for poor connection (such as damaged/pulled-out pins, corrosion).
  • Is there any malfunction?
 Yes Repair or replace the connector and/or terminals, then go to Step 9.
No Go to the next step.
8 INSPECT NEUTRAL SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT 
  • Neutral switch and PCM connectors are disconnected.
  • Turn the ignition switch off.
  • Inspect for continuity between neutral switch terminal A (wiring harness-side) and PCM terminal 2AS (wiring harness-side).
  • Is there continuity?
 Yes Go to the next step.
No Repair or replace the wiring harness for a possible open circuit, then go to the next step.
9 VERIFY TROUBLESHOOTING OF DTC P0850 COMPLETED 
  • Make sure to reconnect all disconnected connectors.
  • Clear the DTC from the PCM memory using the M-MDS.

    (See AFTER REPAIR PROCEDURE ).

  • Operate the shift lever when drive the vehicle more than 30 km/h {19 mph} 8 times alternately.
  • Perform the Pending Trouble Code Access Procedure.

    (See ON-BOARD DIAGNOSTIC TEST ).

  • Is the PENDING CODE same as DTC present?
 Yes Replace the PCM, then go to the next step.
(See PCM REMOVAL/INSTALLATION ).
No Go to the next step.
10 VERIFY AFTER REPAIR PROCEDURE 
 Yes Go to the applicable DTC inspection.
(See DTC TABLE ).
No DTC troubleshooting completed.
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