P0871 on RAM: How to Diagnose & Fix
Transmission Fluid Pressure Sensor/Switch "C" Circuit Range/Performance
1 RAM model · 1 documented issue · $300-$3,500 repair
P0871 on RAM by model: symptoms, diagnosis and fix
The 8-speed (ZF 8HP70 / TorqueFlite) develops a torque-converter clutch shudder felt as a vibration/judder around 30-50 mph light throttle, along with harsh downshifts, drive-engagement slam, and occasional limp mode (stuck in one gear with CEL). Root causes are degraded/aged transmission fluid and worn torque-converter clutch material, sometimes with valve-body or solenoid issues. Ram markets the trans as 'sealed/lifetime fill,' but ZF recommends fluid service every ~40-60k miles, and skipping it drives most of these complaints.
Common Symptoms
- Shudder/vibration at light throttle 30-50 mph
- Harsh or clunky downshifts
- Slam into drive/reverse
- Limp mode (stuck gear) with CEL
- Delayed or flaring shifts
How to Fix
Start with a proper fluid-and-filter service using the correct ZF 8HP fluid (many shudders clear up with fresh fluid) and apply the latest transmission software/TCM updates. If shudder persists, inspect/replace the torque converter; harsh-shift or limp events may require valve-body or solenoid repair. Adopt a 40-60k-mile fluid interval rather than the 'lifetime' claim to prevent recurrence.
Sources for this issue (2)
P0871 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 P0871 mean on a RAM?
P0871 stands for "Transmission Fluid Pressure Sensor/Switch "C" Circuit Range/Performance." This code sets when the transmission control module receives a signal from transmission fluid pressure sensor/switch C that is out of the expected range or implausible for the current conditions. This sensor monitors hydraulic pressure inside the transmission, which the module relies on to control clutch apply and shift quality. Symptoms can include harsh, delayed, or erratic shifts, slipping, or the transmission entering a failsafe mode. The cause is typically the sensor, actual fluid pressure problems, or the wiring. On RAM it is documented across 1 model: 1500.
What are the most common causes of P0871?
The most common causes of P0871 are: Faulty transmission fluid pressure sensor/switch C, Low or degraded transmission fluid, Internal hydraulic leak or low line pressure, Stuck or faulty pressure control solenoid, Wiring or connector issues, Valve body wear or contamination, Faulty transmission control module (less common). The specific cause varies by vehicle.
How much does it cost to fix P0871 on a RAM?
Published repair estimates on RAM range from $300 to $3,500 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 P0871 on a different make?
View P0871 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.