P0871: Transmission Fluid Pressure Sensor/Switch C Circuit Range/Performance
What to do
Ask for all the pressure readings to be compared rather than this one looked at alone — the comparison is where the answer is.
What this code means
The third pressure reading is valid but does not match expectation. Read against the other pressure sensors: agreement points at a shared cause such as fluid or the pump, disagreement locates the loss in the circuit this sensor watches.
Likely causes
Start here
- Worn valve body · specialist
- Low or degraded transmission fluid · easy
- Faulty pressure control solenoid · moderate
Less common
- Worn clutch packs · specialist
- Faulty transmission fluid pressure sensor · moderate
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about P0871.