P0850moderate severityPowertrain
Park/Neutral Switch Input Circuit
on 2007 Ram 3500 5.9L I6 Cummins · 4WD
What this code means
The PCM detects a fault in the park/neutral position switch input circuit. This can affect starting and shift interlock functions.
Symptoms
- No-start in park or neutral
- Incorrect gear indication
- Starter may not engage
Common causes
- Faulty park/neutral switch
- Wiring open or short
- Corroded connector
- Faulty PCM
Diagnostic steps
- Scan and record freeze frame data
- Verify gear position readings with scan tool
- Inspect switch wiring and connector
- Test switch continuity in each gear
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