Low, degraded or contaminated transmission fluid, or a blocked filter, restricting hydraulic pressure; Faulty pressure control solenoid B (stuck, worn or electrical fault in the coil); Damaged, chafed or corroded wiring or connector between the solenoid and the control unit, including internal harness faults; Fluid leaking or contaminated with debris, causing the solenoid or valve body to stick; Worn valve body or internal hydraulic faults, such as worn bores or seals, affecting pressure control; Low battery voltage or poor earth affecting solenoid operation; Faulty transmission control unit or outdated software (model-specific, check manufacturer information).

P0775

Pressure Control Solenoid B.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
7: AreaTransmission
75: FaultThe specific fault in that area

What it means

P0775 is the generic SAE J2012 code for a fault in Pressure Control Solenoid 'B' in the automatic transmission hydraulic control circuit. The transmission control unit has detected that the solenoid circuit or its performance does not match what it commanded, for example an electrical fault or a pressure that does not follow the request. Which solenoid is 'B' and what it controls depends on the make, model and transmission.

Symptoms

Harsh, delayed or flared gear changes
Transmission stuck in one gear (limp mode)
Gearbox warning light or malfunction light on
Slipping or loss of drive under load
Poor fuel economy or high engine revs at a given speed
No lock-up or erratic shifting

Possible causes

Low, degraded or contaminated transmission fluid, or a blocked filter, restricting hydraulic pressurelikely
Faulty pressure control solenoid B (stuck, worn or electrical fault in the coil)likely
Damaged, chafed or corroded wiring or connector between the solenoid and the control unit, including internal harness faultslikely
Fluid leaking or contaminated with debris, causing the solenoid or valve body to stickpossible
Worn valve body or internal hydraulic faults, such as worn bores or seals, affecting pressure controlpossible
Low battery voltage or poor earth affecting solenoid operationpossible
Faulty transmission control unit or outdated software (model-specific, check manufacturer information)rare

How to diagnose

Read all stored codes and freeze frame data, noting the gear, temperature, speed and load when the fault set; check for related transmission or engine codes
Check the transmission fluid level, condition and smell (where a dipstick or check procedure exists), following the manufacturer's method as it varies by model
Visually inspect the transmission wiring and connectors for damage, corrosion, fluid ingress and chafing
Check battery condition and charging voltage, and the earth connections to the transmission control unit
Measure the resistance of solenoid B against specification and check the circuit for shorts, opens and continuity to the control unit
Use a scan tool to command the solenoid and monitor the actual and requested pressure or current, where supported
Check for technical service bulletins and software updates for the specific model and transmission
Drop the pan and inspect for debris or clutch material, then assess the valve body if the electrical checks pass

How to fix

Correct the fluid level or change the fluid and filter with the specified type if it is degraded or contaminated
Repair or replace damaged wiring, connectors or the internal harness
Replace the faulty pressure control solenoid B, or the solenoid pack where it is supplied as an assembly
Clean, repair or replace the valve body if it is worn or contaminated
Repair any battery, charging or earth fault found
Apply an updated control unit calibration only where the manufacturer lists it as a fix for this fault

Can I keep driving?

Medium severity

The car can usually be driven carefully a short distance, for example to a garage, but avoid heavy loads and towing. Continued driving with slipping or harsh shifts can cause serious transmission damage, so have it checked soon.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.