P0870 on 1994-2001 RAM 1500 — Transmission Fluid Pressure Sensor/Switch 'C' Circuit
1 vehicles · 1 makes · $150-$500 repair
How to diagnose and fix P0870: most-reported vehicles
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RAM 1500 · 1994–2001
The electronically-controlled 42RE/46RE automatics regulate shift points with a PWM governor pressure solenoid plus a governor pressure sensor/transducer in the valve body. These parts get contaminated by transmission varnish and wear out. When the sensor feedback no longer matches the commanded pressure, the PCM sets a code and drops the transmission into 'limp' mode — no overdrive, 2nd/3rd-gear start, harsh or no shifts. Extremely common on high-mileage 2nd-gen Rams.
Common Symptoms
- Transmission stuck in limp mode (2nd/3rd gear only)
- No overdrive / no lockup
- Wrong-gear starts
- Harsh or delayed shifts
- Speedometer-related shift errors
How to Fix
Drop the pan and replace the governor pressure solenoid (Mopar 4617210) and the governor pressure sensor/transducer (56028196AD, supersession of 56041403AA); available together as an aftermarket kit (e.g. Hercoo/TransGo). Fresh ATF+4 and a filter at the same time. DIY parts ~$40-$120; shop job $150-$500. Confirms and clears P0748/P1757/P0868 limp-mode codes.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- 1996-1999 42RE/46RE governor pressure transducer 56041403AA family
Verify transmission and connector.
- Mopar 4617210AA governor pressure solenoid
4617210/52118652 family used in supported electronic-governor Chrysler transmissions; confirm the truck's 42RE/46RE tag and VIN.
- 2000-2001 governor solenoid/transducer/filter-gasket kit
Confirm 42RE/46RE and that the included filter matches the pan.
- Mopar 68218057AB ATF+4, one quart
Verify manual and level procedure.
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Sources for this issue (2)
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P0870 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0870 mean?
P0870 stands for "Transmission Fluid Pressure Sensor/Switch 'C' Circuit." General fault in the transmission fluid pressure sensor/switch 'C' circuit. Signal missing or implausible.
What are the most common causes of P0870?
The most common causes of P0870 are: Faulty pressure sensor/switch C, Open or shorted wiring, Corroded connector, Internal TCM fault. The specific cause varies by vehicle.
How much does it cost to fix P0870?
Repair costs for P0870 range from $150 to $500, depending on the vehicle and root cause.
Which vehicles are affected by P0870?
Au7o has documented P0870 across 1 vehicle models from 1 manufacturers: RAM.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.