What Does P0798 Mean?
The TCM has detected an electrical fault in the pressure control solenoid C circuit. This is specifically an electrical diagnosis, indicating problems such as an open circuit, short to ground, short to power, or resistance out of range in the solenoid's wiring or the solenoid itself. The solenoid may not be receiving proper commands from the TCM.
Common Causes
30%
Pressure control solenoid C internal coil failure (open or shorted windings)
25%
Corroded or damaged connector at solenoid C
25%
Wiring fault between TCM and solenoid C (open, short, or high resistance)
12%
TCM solenoid driver circuit failure
8%
Transmission fluid contamination in electrical connector causing short
Diagnostic Steps
1
Measure pressure control solenoid C resistance at the transmission connector — compare to manufacturer specification (typically 3-8 ohms).
2
Check for continuity and proper resistance from the TCM connector to the solenoid connector to verify wiring integrity.
3
Inspect the solenoid connector for transmission fluid contamination, corroded pins, or backed-out terminals.
4
Test for short to ground and short to power on both solenoid circuit wires.
5
If the solenoid and wiring test good, swap solenoid connectors with an adjacent known-good solenoid to isolate the fault to the TCM driver.
6
Check for TSBs regarding transmission internal harness failures for your specific vehicle.
Estimated Repair Cost
$150 - $900
Parts + labor, varies by vehicle and location
The TCM has detected an electrical fault in the pressure control solenoid C circuit. This is specifically an electrical diagnosis, indicating problems such as an open circuit, short to ground, short to power, or resistance out of range in the solenoid's wiring or the solenoid itself. The solenoid ma...
The most common cause of P0798 (Pressure Control Solenoid C Electrical) is: Pressure control solenoid C internal coil failure (open or shorted windings)
Typical repair costs for P0798 range from $150 to $900, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Transmission shift quality will be degraded, and limp mode may be activated. The vehicle can be driven at reduced speeds for short distances. Avoid high-speed or heavy-load driving until the electrical fault is resolved.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0798 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission
Difficulty
Type
Generic (SAE)
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
