Transmission Fluid Pressure Sensor/Switch 'C' Circuit High
Indicates high voltage in the transmission fluid pressure sensor circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The computer is reading a voltage level from the transmission fluid pressure sensor that’s too high, usually suggesting a sensor issue or wiring fault.
What the computer is actually seeing
The transmission control module (TCM) sees a voltage from the sensor above the expected range, typically over 4.5 volts, indicating a potential fault with the sensor or its circuit.
What a healthy reading looks like
Transmission fluid pressure sensors should output a voltage between 0.5V to 4.5V under normal operating conditions, with expected pressure values varying based on vehicle conditions.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Check transmission fluid level and condition; add or replace fluid if low or contaminated. Decision: If fluid condition is poor, service fluid and retest.
- 22. Inspect wiring and connectors to the transmission fluid pressure sensor for signs of damage or corrosion. Decision: If damaged, repair or replace wiring/connectors and retest.
- 33. Use a digital multimeter to measure the voltage coming from the fluid pressure sensor with the ignition on and the engine off. Decision: If the voltage is above 4.5V, replace the sensor.
- 44. If sensor voltage is good but code persists, check the TCM for faults or programming issues.
Common causes
- Faulty transmission fluid pressure sensor
- Short circuit in the wiring
- Open circuit in the wiring
- Poor connection at the sensor plug
- Improper transmission fluid levels
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally drivable, but symptoms like slipping or harsh shifting could worsen, so fix soon.
Will this code come back after clearing?
If the underlying issue isn’t resolved, yes, it will likely return.
Why does this code pair with P0841 or P0842?
Those codes also relate to the transmission fluid pressure sensor and indicate specific circuit issues.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →