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1994-2007 DODGE RAM 2500
5.9L I6 Cummins Diesel•4WD•AUTOMATIC•diesel•turbo
22 active safety recalls on this vehicle — view recalls🏆Sponsored by Timmehster
Repairs485Labor512Torque3106Fluid10DTC1718Battery1Maintenance0Recalls22
P0840moderate severityPowertrain

Transmission Fluid Pressure Sensor/Switch A Circuit

on 1994-2007 Dodge Ram 2500 5.9L I6 Cummins Diesel · 4WD

What this code means

The PCM detected a problem in the transmission fluid pressure sensor or switch circuit A. This can cause incorrect line pressure readings and affect shift quality.

Symptoms

  • Harsh or erratic shifting
  • Transmission warning light on
  • Possible limp mode

Common causes

  • Faulty transmission fluid pressure sensor
  • Damaged wiring or connector
  • Low or dirty transmission fluid
  • Internal transmission pressure fault

Diagnostic steps

  1. Scan for codes and check freeze frame data
  2. Check transmission fluid level and condition
  3. Inspect sensor wiring and connector
  4. Test sensor resistance and compare to spec
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