P0745
Pressure Control Solenoid A.
- Generic
- Powertrain
- Generic code
- High severity
How this code is built
- P
- SystemPowertrain
- 0
- Defined bySAE, the same on every car
- 7
- AreaTransmission
- 45
- FaultThe specific fault in that area
What it means
P0745 is the generic code for a fault in the Pressure Control Solenoid 'A' circuit or its performance in the automatic transmission. The solenoid regulates hydraulic line pressure, which controls how firmly clutches and bands engage. The transmission control unit set the code because the commanded solenoid current or electrical state did not match what it measured, or because actual line pressure or shift behaviour did not match the command.
Symptoms
- Harsh, delayed or flared gear changes
- Transmission stuck in one gear (limp mode)
- Gearbox warning light or malfunction indicator lamp on
- Slipping or loss of drive under load
- Poor fuel economy or high engine revs at a given speed
- Shift quality changes noticeably between cold and hot
Possible causes
- Faulty pressure control solenoid (open or short circuit, sticking or worn)likely
- Damaged, chafed or corroded wiring or connector between the solenoid and the transmission control unit, including the internal harnesslikely
- Low, degraded or contaminated transmission fluid, or a blocked filter, affecting pressure and solenoid operationlikely
- Debris or wear in the valve body causing the solenoid or pressure regulator valve to stickpossible
- Low or unstable supply voltage to the transmission control unit from a weak battery or poor earthpossible
- Internal transmission wear causing pressure loss (worn pump, seals or clutches)possible
- Fault in the transmission control unit driver circuitrare
How to diagnose
- Read all stored and pending codes and the freeze frame data, noting road speed, gear, fluid temperature and voltage when it set
- Check the transmission fluid level and condition (colour, smell, debris) using the manufacturer's procedure, as the method varies by model
- Check battery condition and charging voltage, and inspect main earths for security and corrosion
- Inspect the transmission connector and harness for damage, corrosion, fluid ingress or chafing
- Measure the solenoid resistance and compare it with the manufacturer's specification, which depends on the transmission
- Test the wiring for continuity, short to earth and short to supply between the solenoid and control unit
- Use live data to compare commanded and actual line pressure or solenoid current during a road test, where the transmission supports it
- Check for technical service bulletins and software updates for the specific transmission, then inspect the pan and valve body for metal or clutch debris if the electrical tests pass
How to fix
- Repair or replace damaged wiring, terminals or the connector
- Replace the pressure control solenoid, or the solenoid pack or valve body where it is supplied as an assembly
- Correct the fluid level, or change the fluid and filter with the specified type
- Clean or overhaul the valve body to free sticking valves, replacing worn parts
- Restore good battery and earth condition to give the control unit a stable supply
- Repair or overhaul the transmission if internal wear is found, and update the control unit software only if an outdated calibration is a known cause for that model
Can I keep driving?
Avoid driving beyond a short, gentle trip to a workshop. Incorrect line pressure can cause clutch slip and rapid internal damage, and the car may drop into limp mode without warning.
Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.