P0874Transmission Fluid Pressure Sensor/Switch C Circuit Intermittent
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Transmission fluid pressure switches C and D report whether a clutch circuit is pressurised. They are more widespread than A and B: GM's 6L80/6L90 and 6T40/6T70 six-speeds put switch C on the 2-6 brake and D on the 1-2-3-4 clutch, Allison uses them for its third shift valve and its reverse switch, Ram's RFE gearboxes for the clutch pressure switches in the solenoid block. Ford reports pressure faults under its solenoid codes. P0874 reports short dropouts or flutter of the C signal without a lasting low or high. It is documented only in GM bulletin 21-NA-033 for the Corvette C8 dual clutch, with MIL: dirt and sticking valves are cleaned, the clutches relearned, and only then the circuit traced. Thresholds are not published.
- What you may notice
- Warning lamp coming and going
- Occasional harsh shift or limp mode
- Likely causes
- LikelyLoose contact or corrosion at connector or harness
- PossibleDirt or sticking valve (dual clutch)
- PossibleSensor or switch with dropouts
- RareLow fluid level, pressure drops in corners
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €100 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.