Diagnostic Procedure
WARNING: This page is about a different car, the 2005 Jeep Liberty. However, it is still accessible from the selected car via links, so may be relevant.
P0850-PARK/NEUTRAL SWITCH PERFORMANCE DIAGNOSTIC TEST REFERENCE
| TEST | ACTION | APPLICABILITY |
|---|---|---|
| 1 | Ignition on, engine not running. With the DRBIII®, read the Park/Neutral Position Switch input state. While moving the gear selector through all gear positions (Park to 1 and back to Park), monitor the DRB display. Did the DRB display show P/N and D/R in the correct gear positions? Yes --> Refer to the INTERMITTENT CONDITION SYMPTOM . Perform POWERTRAIN VERIFICATION TEST VER - 2 . No --> Go To 2 |
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| 2 | Turn the ignition off. Disconnect the PCM harness connectors. Disconnect the Transmission Range Sensor harness connector.
CAUTION:
DO NOT PROBE THE PCM HARNESS CONNECTORS. PROBING THE PCM HARNESS CONNECTORS WILL DAMAGE THE PCM TERMINALS RESULTING IN POOR TERMINAL TO PIN CONNECTION. INSTALL MILLER SPECIAL TOOL #8815 TO PERFORM DIAGNOSIS. Measure the resistance of the TRS T41 Sense (P/N Sense) circuit from the TRS harness connector to the appropriate terminal of special tool #8815 installed. Is the resistance below 5.0 ohms? Yes --> Go To 3 No --> Repair the open in the TRS T41 Sense (P/N Sense) circuit. Perform POWERTRAIN VERIFICATION TEST VER - 2 . |
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| 3 | Measure the resistance between ground and the TRS T41 Sense (P/N Sense) circuit at the TRS harness connector. Is the resistance above 100k ohms? Yes --> Go To 4 No --> Repair the short to ground in the TRS T41 Sense (P/N Sense) circuit. Perform POWERTRAIN VERIFICATION TEST VER - 2 . |
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| 4 | Connect the Transmission Range Sensor harness connector. Move the Gear selector through all gear positions, from Park to 1st and back. While moving the gear selector through each gear, measure the resistance between ground and the TRS T41 Sense (P/N Sense) circuit using special tool #8815.
NOTE:
The circuit is grounded in Park and Neutral and open in the other positions. Did the resistance change from above 100 kohms (open) to below 10.0 ohms (grounded)? Yes --> Go To 5 No --> Replace the Transmission Range Sensor. Perform POWERTRAIN VERIFICATION TEST VER - 2 . |
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| 5 |
NOTE:
Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary. Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.If there are no possible causes remaining, view repair.RepairReplace and program the Powertrain Control Module per Service Information.Perform POWERTRAIN VERIFICATION TEST VER - 2 . |
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