P0747: Pressure Control Solenoid A Stuck On
The P0747 code indicates that the transmission control module (TCM) has detected that the pressure control solenoid 'A' is stuck in the 'on' position, meaning it is commanding maximum pressure or staying open when it should be modulating. This solenoid regulates hydraulic pressure to the transmission's clutches and bands. When stuck on, it can cause harsh shifts, slipping, or transmission overheating. Common causes include a faulty solenoid, dirty transmission fluid, or internal wiring issues.
1. Symptoms You Will Notice
- Harsh or delayed shifts
- Transmission slipping or overheating
- Check Engine Light illuminated
- Reduced fuel economy
2. Most Common Causes
- Faulty or internally worn pressure control solenoid
- Failed transmission control module (TCM)
- Solenoid wiring shorted to ground or battery voltage
- Corroded, oxidized, or damaged solenoid connector pins
- Sediment buildup or contaminated transmission fluid causing mechanical sticking of the solenoid
- Excessive electrical resistance in the solenoid circuit
3. Step-by-Step Diagnosis
Step 1: Scan for codes and verify P0747 is present.
Step 2: Check transmission fluid level and condition; replace if dirty or low.
Step 3: Inspect wiring and connectors to the pressure control solenoid for damage or corrosion.
Step 4: Test solenoid resistance and operation using a multimeter; replace if out of spec.
Step 5: If solenoid and wiring are good, perform a transmission pressure test to rule out internal issues.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the transmission may overheat or fail, leading to costly repairs. Short trips to a repair shop are acceptable if shifting is not severely affected.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor. Replacing the solenoid is often $100-$200, plus diagnostic fees.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.