Auxiliary Transmission Fluid Pump Control Module Circuit Open
The P0C23 code indicates an open circuit in the control module of the auxiliary transmission fluid pump. This pump is used in hybrid and electric vehicles to circulate transmission fluid when the main engine is off, ensuring proper lubrication and cooling. An open circuit means there is a break in the electrical path, preventing the pump from operating. This can lead to transmission overheating and potential damage.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission overheating warning
- Reduced fuel economy
- Transmission slipping or harsh shifting
2. Most Common Causes
- Open or shorted wiring in the pump control circuit
- Faulty auxiliary transmission fluid pump control module
- Damaged auxiliary transmission fluid pump motor
- Corroded or loose electrical connectors
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and freeze frame data.
Step 2: Visually inspect the auxiliary pump wiring and connectors for damage or corrosion.
Step 3: Test the pump control module power and ground circuits with a multimeter.
Step 4: Check the pump motor resistance and compare to specifications.
Step 5: If circuits are intact, replace the auxiliary transmission fluid pump control module.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Driving with an open circuit can cause transmission overheating and potential failure, leading to costly repairs.
How much does it cost to fix?▼
Repair costs typically range from $150 to $400, including parts and labor, depending on the exact cause and vehicle model.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.