Pressure Control Solenoid "B" Control Circuit Low
P0966 indicates the transmission control module detected low voltage or an open circuit in the Pressure Control Solenoid B control circuit. This solenoid regulates transmission fluid pressure, and when the circuit fails, the transmission may enter limp mode to protect itself from damage.
What You Might Notice
- Check Engine Light illuminated
- Transmission shifts hard or slips during gear changes
- Increased fuel consumption
- Transmission overheating
- Transmission stuck in limp mode or safe mode
Most Common Causes
- 1
Solenoid wiring fault
Broken, corroded, or loose wiring connections to the Pressure Control Solenoid B causing loss of signal.
- 2
Faulty solenoid
The Pressure Control Solenoid B itself has failed internally or burned out, preventing proper circuit operation.
- 3
Transmission fluid level low
Low transmission fluid can affect solenoid operation and circuit resistance, triggering the code.
- 4
PCM or connector issues
Damaged transmission control module connectors or PCM circuit board defects can prevent proper solenoid control.
How to Diagnose It
- 1
Check Solenoid wiring fault — Broken, corroded, or loose wiring connections to the Pressure Control Solenoid B causing loss of signal.
- 2
Check Faulty solenoid — The Pressure Control Solenoid B itself has failed internally or burned out, preventing proper circuit operation.
- 3
Check Transmission fluid level low — Low transmission fluid can affect solenoid operation and circuit resistance, triggering the code.
- 4
Check PCM or connector issues — Damaged transmission control module connectors or PCM circuit board defects can prevent proper solenoid control.
How to Fix It
- 1
Inspect and repair wiring
Examine all wiring and connectors leading to Pressure Control Solenoid B for corrosion, breaks, or loose connections. Clean connectors and repair or replace damaged wiring as needed.
- 2
Replace Pressure Control Solenoid B
If wiring is intact, replace the faulty solenoid with a new OEM or quality aftermarket unit to restore proper pressure control.
- 3
Check transmission fluid level
Verify transmission fluid level is at the correct mark on the dipstick. Top off with the recommended fluid type if low.
- 4
Inspect transmission connector and PCM
Check the transmission control module connector pins for damage or corrosion. If connector appears faulty, repair or replace. If problem persists, the PCM may need reprogramming or replacement.
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