P0747: Pressure Control Solenoid A Stuck On

What it means

Pressure control solenoid A appears stuck on. The code alone does not establish the resulting line pressure or cause.

At a glance

• Usually lights the check-engine light
• The engine or gearbox may go into limp mode

How it works

Pressure control solenoid A directs hydraulic flow when commanded by the transmission module. P0747 means the module detects that solenoid A appears stuck on, but the code alone does not establish the resulting pressure or why the valve is stuck. The transmission may shift abnormally as a result.

Common causes

Most likely first.

1. Solenoid stuck on mechanically
2. Valve body contamination
3. Carbon or debris buildup preventing free movement

Symptoms

• Transmission may shift harshly or abnormally
• Check engine or transmission warning light on

How to diagnose it

1. Record freeze-frame data and review solenoid A command, gear, and pressure-related live data to determine when the stuck-on condition is reported.
2. Check transmission fluid level and condition using the manufacturer's procedure and look for signs of contamination that could affect valve movement.
3. Inspect solenoid A’s wiring and connector for shorts, damaged insulation, corrosion, or loose terminals.
4. Test solenoid A’s coil and circuit against the manufacturer's specification to distinguish an electrical fault from a mechanical sticking problem.
5. If the circuit passes, inspect the valve body and solenoid A passage for contamination or restricted movement using the manufacturer's procedure.

Common fixes

• Clean and secure solenoid A’s connector or repair damaged terminals.
• Repair wiring shorted to ground or supply in solenoid A’s circuit.
• Replace solenoid A if testing confirms it is stuck or electrically faulty.
• Clean or repair a contaminated valve body passage that prevents solenoid A from moving freely.
• Correct a fluid condition that is contributing to sticking, following the manufacturer's service procedure.

Can I keep driving?

Avoid driving if shifts become very harsh, the transmission slips, or the vehicle is limited to an unsuitable gear; arrange repair promptly. Abnormal pressure control can worsen shift quality and lead to internal transmission damage.