P0798: Pressure Control Solenoid C Electrical
Severity: high
What it means: P0798 means the computer found an electrical problem with transmission pressure control solenoid 'C', which controls fluid pressure to a clutch inside the automatic transmission. Bad pressure control can cause slipping, flare (revving between gears) or harsh shifts.
Safe to drive? Drive gently and get it checked soon. Slipping gets worse and can damage the transmission.
Common symptoms
- Check engine light
- Engine flares or slips between gears
- Harsh or delayed shifts, possible limp mode
Likely causes, ranked
- Shorted or failed solenoidShop
- Wiring or connector faultShop
- Transmission computer faultShop
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Vehicle-specific notes
- 2002–2006 Mazda MPV: A tech said he fixed a 2002 MPV's 2-3 slip by replacing a shorted high clutch solenoid (P0798) for about $130. Read the full answer · Source
DIY or shop?
Fluid checks are DIY. Solenoid and wiring diagnosis is shop work.
Before you replace parts
- Read the codes with a scan tool that talks to the transmission computer.
- Check the transmission fluid level and condition.
- Inspect the transmission wiring harness and connectors for damage, corrosion or shorts.
- Have the solenoid resistance and circuit tested before replacing the solenoid or computer.
- Check your VIN for recalls, service bulletins and software updates.
Safety / mechanic note
Verify with a mechanic. A slipping transmission can lose drive in traffic. A code points to a circuit or system, not always a specific part.
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