P0850

P0850-PARK/NEUTRAL SWITCH PERFORMANCE



- When Monitored:
Continuously with the transmission physically in Drive, vehicle not in Limp-in mode, vehicle speed above 16 kph (10 mph), and throttle position at least 25%.

- Set Condition:
This code will set if the PCM detects an irrational Park/Neutral switch state for at least one minute. 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 may result in possible serious or fatal injury.

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 DTC Active at this time?

Yes

- Go to 2

No

- Refer to the *CHECKING FOR AN INTERMITTENT DTC Diagnostic Procedure. Checking for an Intermittent DTC

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, refer to the Communication Category and 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

- Perform the appropriate diagnostics.

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. Refer to the appropriate diagnostic procedures in the Transmission category.
2. Inspect the P/N switch. Refer to the appropriate diagnostic procedures in the Transmission category.
3. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors between the Transmission Range Sensor, the TCM, and the PCM.
4. Look for any chafed, pierced, pinched, or partially broken wires.
5. Look for broken, bent, pushed out or corroded terminals.
6. Search for any Technical Service Bulletins that may apply.

Were any problems found?

Yes

- Repair as necessary.
- Perform the PCM Verification Test. PCM Verification Test

No

- Replace and program the PCM.
- Perform the PCM Verification Test. PCM Verification Test