What Does P0781 Mean?
The TCM has detected that Pressure Control Solenoid B is stuck in the on (energized) position. This is a variant code from P0777 and on some platforms represents a 1-2 shift malfunction. The solenoid is continuously applying pressure when it should be modulating, which can cause excessively high line pressure and very harsh shift engagements that stress internal components.
Common Causes
35%
Pressure control solenoid B mechanically stuck in the open/applied position
25%
Wiring short to power keeping the solenoid circuit energized
20%
Valve body bore wear causing the solenoid plunger to bind in the on position
12%
TCM driver circuit stuck high, continuously powering the solenoid
8%
Contaminated transmission fluid causing internal spool valve to stick
Diagnostic Steps
1
With key on engine off, check if PCS B shows as energized in live data — if yes without being commanded, suspect electrical short or TCM fault.
2
Disconnect the solenoid connector and measure solenoid resistance to verify coil integrity and check for internal short.
3
With the solenoid disconnected, check the harness for a short to battery voltage on the solenoid control wire.
4
Perform a line pressure test — consistently high pressure across all ranges confirms the stuck-on condition.
5
Inspect the valve body for debris or wear in the PCS B bore that could cause the plunger to bind in the applied position.
Estimated Repair Cost
$250 - $1,500
Parts + labor, varies by vehicle and location
The TCM has detected that Pressure Control Solenoid B is stuck in the on (energized) position. This is a variant code from P0777 and on some platforms represents a 1-2 shift malfunction. The solenoid is continuously applying pressure when it should be modulating, which can cause excessively high lin...
The most common cause of P0781 (Pressure Control Solenoid B Stuck On) is: Pressure control solenoid B mechanically stuck in the open/applied position
Typical repair costs for P0781 range from $250 to $1,500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Harsh, slamming shifts from excessive line pressure can be jarring and may damage driveline components over time. While the vehicle can be driven, the abrupt shift engagements may be startling. Limit driving to necessary trips and have it repaired promptly.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0781 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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