Powertrain Control Module (PCM)

P0850-PARK/NEUTRAL SWITCH PERFORMANCE

For a complete wiring diagram, refer to the Wiring Information.

- When Monitored:
Continuously with the transmission in Park, Neutral, or Drive and not in Limp-in mode.

- Set Condition:
This code will set if the Powertrain Control Module (PCM) detects an irrational Park/Neutral switch state. Two trip fault. Three good trips to turn off the MIL.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. DTC IS ACTIVE
1. Start the engine and allow it to reach operating temperature.

WARNING: When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts, or fan. Do not wear loose clothing. Failure to follow these instructions can result in personal injury or death.

2. With the scan tool select View DTCs.

NOTE: If the DTC does not reset it may be necessary to test drive the vehicle.

Is the status Active for this DTC?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION diagnostic procedure. Intermittent Condition Test

2. DTCS PRESENT IN THE TRANSMISSION CONTROL MODULE (TCM)

NOTE: If the scan tool is unable to communicate with the TCM, or if there are related communication DTCs present, perform the appropriate diagnostic procedure.

1. Turn the ignition on.
2. With the scan tool, select View DTCs in the TCM.

Are there any DTCs present in the TCM?

Yes

- Testing and Inspection Perform the appropriate diagnostic procedure.

No

- Go To 3

3. POWERTRAIN CONTROL MODULE (PCM)
1. Inspect the P/N signal circuit for a short to ground, or a short to voltage with the shifter in Drive or Reverse. Perform the appropriate diagnostic procedures in the Transmission category.
2. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Transmission Range Sensor, the TCM, and the PCM.
3. Look for any chafed, pierced, pinched, or partially broken wires.
4. Look for broken, bent, pushed out or corroded terminals.
5. Perform any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test

No

- Replace and program the Powertrain Control Module. PCM/ECM Reprogramming
- Perform the POWERTRAIN VERIFICATION TEST. Powertrain Verification Test