What Does P0797 Mean?
Pressure control solenoid C is stuck in the on (open) position, continuously applying hydraulic pressure when it should be modulated or released. This causes excessive clamping force on the associated clutch pack, resulting in harsh engagement, bind-up during shifts, or the inability to release a gear properly. The transmission may feel like it is fighting against itself during certain shifts.
Common Causes
35%
Pressure control solenoid C mechanically stuck open due to debris or varnish
25%
Solenoid C shorted internally, remaining energized regardless of TCM command
15%
Wiring short to power keeping solenoid C continuously energized
15%
Valve body stuck valve in solenoid C pressure circuit
10%
Degraded transmission fluid with heavy varnish deposits
Diagnostic Steps
1
Monitor solenoid C command status — verify the TCM is commanding it off while checking if pressure remains applied.
2
Command the solenoid off with a bi-directional scan tool and measure line pressure in the associated circuit — it should drop to zero/base.
3
Check for a wiring short to power on the solenoid C control wire by disconnecting the solenoid and measuring voltage at the harness.
4
If no electrical short exists, remove and inspect the solenoid for debris, varnish, or mechanical binding.
5
Inspect the valve body for stuck valves in the solenoid C pressure delivery circuit.
6
Flush the transmission and replace the filter if fluid is heavily contaminated.
Estimated Repair Cost
$200 - $1,100
Parts + labor, varies by vehicle and location
Pressure control solenoid C is stuck in the on (open) position, continuously applying hydraulic pressure when it should be modulated or released. This causes excessive clamping force on the associated clutch pack, resulting in harsh engagement, bind-up during shifts, or the inability to release a ge...
The most common cause of P0797 (Pressure Control Solenoid C Stuck On) is: Pressure control solenoid C mechanically stuck open due to debris or varnish
Typical repair costs for P0797 range from $200 to $1,100, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Harsh, abrupt shifts or gear binding can occur, potentially causing the vehicle to lurch unexpectedly. This is a moderate safety concern, especially in traffic. Drive only if necessary at low speeds and schedule immediate repair to prevent transmission damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0797 to identify the root cause.
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Quick Info
Category
Powertrain
System
Automatic Transmission
Difficulty
Type
Generic (SAE)
Recommended Tools
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