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2007 RAM 3500
5.9L I6 Cummins•4WD•diesel•ISB•turbo
1 active safety recall on this vehicle — view recalls🏆Sponsored by Timmehster
Repairs487Labor523Torque138Fluid11DTC1714Battery1Maintenance0Recalls1
P0851moderate severityPowertrain

Park/Neutral Switch Input Circuit Low

on 2007 Ram 3500 5.9L I6 Cummins · 4WD

What this code means

The PCM sees a low voltage input from the park/neutral position switch. This may affect starting and gear-related engine functions.

Symptoms

  • No-start in Park or Neutral
  • Incorrect gear display
  • Backup lights inoperative

Common causes

  • Faulty park/neutral switch
  • Short to ground in circuit
  • Loose or corroded connector
  • Failed transmission range sensor

Diagnostic steps

  1. Retrieve codes and check freeze frame
  2. Inspect PNP switch wiring for shorts
  3. Test switch continuity across gear positions
  4. Replace faulty switch or sensor
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