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 typically found in hybrid or electric vehicles to circulate transmission fluid when the main engine is off. An open circuit means there is a break in the electrical path, preventing the pump from operating. This can lead to inadequate transmission fluid circulation, potentially causing overheating and damage to the transmission.
01. Most Common Causes
- Faulty auxiliary transmission fluid pump control module
- Open or shorted wiring in the pump circuit
- Blown fuse or relay for the pump
- Corroded or loose electrical connectors
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission overheating
- Reduced fuel economy
- Transmission slipping or harsh shifting
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to confirm the code and check for related codes.
Step 2: Visually inspect the wiring and connectors for damage, corrosion, or looseness.
Step 3: Test the fuse and relay for the auxiliary pump circuit.
Step 4: Measure voltage and ground at the pump control module connector.
Step 5: If power and ground are present, test the pump motor itself for continuity.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive with this code, as the auxiliary pump failure can lead to transmission overheating and damage, especially in stop-and-go traffic or when the engine is off.
How much does it cost to fix?▼
The cost to fix P0C23 typically ranges from $150 to $400, including parts and labor. The exact cost depends on whether the issue is a simple wiring repair or requires replacement of the pump control module.