P0964: Pressure Control Solenoid 'C' Control Circuit/Open
The P0964 code indicates that the Powertrain Control Module (PCM) has detected an open or malfunction in the electrical circuit for pressure control solenoid 'C'. This solenoid regulates hydraulic pressure to the transmission's shift valves, affecting shift timing and quality. An open circuit means there is no continuity, often due to a broken wire, damaged connector, or internal solenoid failure. This can lead to harsh or delayed shifts, slipping, or even transmission damage if ignored.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Harsh or erratic shifting
- Transmission slipping or delayed engagement
- Reduced fuel economy
2. Most Common Causes
- Faulty pressure control solenoid 'B' with an open coil
- Damaged, corroded, or broken wiring between the TCM and the solenoid
- Loose, corroded, or damaged pins in the solenoid connector
- Internal failure of the transmission control module (TCM)
- Poor ground in the solenoid circuit
- Short to ground or voltage in the solenoid control wire
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Visually inspect wiring and connectors for damage or corrosion.
Step 3: Measure resistance of solenoid 'C' (typically 4-6 ohms).
Step 4: Check for voltage and ground at the solenoid connector with key on.
Step 5: If wiring and solenoid are good, test PCM output or replace PCM.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with an open solenoid circuit can cause harsh shifts, transmission slipping, and potential internal damage. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
Repair costs typically range from $200 to $600, depending on the cause. A solenoid replacement may cost $150-$400 for parts and labor, while wiring repairs are usually less. PCM replacement is more expensive.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.