P0870 on RAM: How to Diagnose & Fix
Transmission Fluid Pressure Sensor/Switch 'C' Circuit
1 RAM model · 1 documented issue · 1 critical · $150-$500 repair
P0870 on RAM by model: symptoms, diagnosis and fix
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)
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 on a RAM?
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. On RAM it is documented across 1 model: 1500.
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 on a RAM?
Published repair estimates on RAM range from $150 to $500 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for P0870 on a different make?
View P0870 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.