Faulty pressure control solenoid 'C' internally stuck in the on position; Contaminated transmission fluid or debris blocking the solenoid valve; Damaged or shorted wiring to the solenoid, causing it to stay energized; Transmission control module software or hardware fault incorrectly commanding the solenoid; Valve body wear or sticking valves that prevent proper pressure control; Low transmission fluid level or degraded fluid affecting solenoid operation

DTC codes / P07xx · Transmission / P0797

P0797Pressure Control Solenoid 'C' Stuck On

Q: What does code P0797 mean?

Pressure Control Solenoid 'C' Stuck On. P0797 indicates that the transmission control module has detected a fault where pressure control solenoid 'C' is stuck in the energized or 'on' state, meaning it is commanding hydraulic pressure when it should not be. The computer typically recognizes this by comparing the commanded solenoid state to the resulting hydraulic pressure or electrical feedback, and it sets the code when the solenoid remains engaged longer than expected.

P0797 indicates that the transmission control module has detected a fault where pressure control solenoid 'C' is stuck in the energized or 'on' state, meaning it is commanding hydraulic pressure when it should not be. The computer typically recognizes this by comparing the commanded solenoid state to the resulting hydraulic pressure or electrical feedback, and it sets the code when the solenoid remains engaged longer than expected.

SystemPowertrain

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaTransmission

Symptoms you may notice

Harsh or delayed transmission shifts, especially when the solenoid should be off
Transmission may enter limp mode or fail-safe mode with reduced performance
Illuminated check engine light or transmission warning light
Slipping or flaring during gear changes
Often no symptoms besides the warning light, especially if the fault is intermittent

Common causes, most likely first

Faulty pressure control solenoid 'C' internally stuck in the on position
Contaminated transmission fluid or debris blocking the solenoid valve
Damaged or shorted wiring to the solenoid, causing it to stay energized
Transmission control module software or hardware fault incorrectly commanding the solenoid
Valve body wear or sticking valves that prevent proper pressure control
Low transmission fluid level or degraded fluid affecting solenoid operation

How to diagnose and fix it

Verify the code with a scan tool and check for any related transmission codes
Inspect the transmission fluid level and condition; top off or replace if contaminated
Perform a visual inspection of the solenoid wiring and connectors for damage or corrosion
Test the solenoid's electrical resistance and compare to manufacturer specifications
Check solenoid operation with a bidirectional scan tool to command it on and off while monitoring pressure
If the solenoid is faulty, replace it and perform any required adaptation or relearn procedure
If the valve body or internal transmission components are worn, repair or replace as needed

Don't overlook wiring and fluid condition

A stuck-on solenoid can sometimes be caused by a short to power in the wiring harness rather than the solenoid itself, so always check the circuit before replacing parts.
Debris from a failing torque converter or clutch material can lodge in the solenoid valve, mimicking an electrical failure and causing the code to return after replacement.
Some vehicles require a transmission control module relearn or adaptation reset after solenoid replacement, and skipping this step can leave the code stored or cause poor shift quality.
The code may set intermittently due to temperature-related resistance changes in the solenoid, so a cold-start test can help confirm the fault.
A faulty transmission control module can command the solenoid on incorrectly, so module diagnostics should be considered if the solenoid and wiring test good.

Can I keep driving with P0797?

It is generally safe to drive short distances to a repair shop, but avoid aggressive acceleration or heavy towing because the transmission may shift harshly or enter limp mode. Prolonged driving with this code can lead to further transmission damage, so schedule diagnosis soon.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.