DTC P0850

BHE010200800W01

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 is available.
• The DTC is stored in the PCM memory.

POSSIBLE CAUSE

• Neutral switch malfunction
• Connector or terminal malfunction
• Open circuit in wiring harness between neutral switch terminal 2A and PCM terminal 2O
• Short to GND in wiring harness between neutral switch terminal 2A and PCM terminal 2O
• Open circuit in wiring harness between neutral switch terminal 1A and GND
• PCM malfunction

Diagnostic procedure

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA HAS BEEN RECORDED

• Has FREEZE FRAME DATA been recorded?
Yes
Go to the next step.
No
Record the FREEZE FRAME DATA on the repair order, then go to the next step.
2

VERIFY RELATED REPAIR INFORMATION AVAILABILITY

• Verify related service 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 terminal, then go to Step 9.
No
Go to the next step.
4

INSPECT NEUTRAL SWITCH GND CIRCUIT FOR OPEN CIRCUIT

• Turn the ignition switch off.
• Inspect for continuity between neutral switch terminal 1A (wiring harness-side) and body GND.
• Is there any 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 GND

• Turn the ignition switch off.
• Inspect for continuity between neutral switch terminal 2A (wiring harness-side) and body GND.
• Is there any continuity?
Yes
Repair or replace the wiring harness for a possible short to GND, then go to Step 9.
No
Go to the next step.
6

INSPECT NEUTRAL SWITCH

• Inspect the neutral switch.
• Is there any malfunction?
Yes
Replace the neutral switch, then go to Step 9.
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 terminal, then go to Step 9.
No
Go to the next step.
8

INSPECT NEUTRAL SWITCH SIGNAL CIRCUIT FOR OPEN CIRCUIT

• Turn the ignition switch off.
• Inspect for continuity between neutral switch terminal 2A (wiring harness-side) and PCM terminal 2O (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 WDS or equivalent.
• Operate the shift lever when drive the vehicle more than 30 km/h {19 mph} 8 times alternately.
• Is the PENDING CODE same as DTC present?
Yes
Replace the PCM, then go to the next step.
No
Go to the next step.
10

VERIFY AFTER REPAIR PROCEDURE

• Perform the "AFTER REPAIR PROCEDURE".
• Are any DTCs present?
Yes
Go to the applicable DTC inspection.
(See DTC TABLE.)
No
DTC troubleshooting completed.