Auxiliary Transmission Fluid Pump Motor Current Low
The P0C27 code indicates that the powertrain control module (PCM) has detected a lower than expected current draw from the auxiliary transmission fluid pump motor. This pump is responsible for circulating transmission fluid to cool and lubricate the transmission, especially during stop-start events or when the engine is off. Low current can result from a failing pump motor, wiring issues, or a faulty control module, potentially leading to inadequate transmission cooling and premature wear.
01. Most Common Causes
- Faulty auxiliary transmission fluid pump motor
- Open or shorted wiring in the pump circuit
- Poor electrical connection at the pump or PCM
- Failed PCM or transmission control module
02. Symptoms You Will Notice
- Transmission overheating
- Check Engine Light illuminated
- Reduced fuel economy due to transmission inefficiency
- Possible transmission slipping or harsh shifting
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to retrieve all codes and freeze frame data.
Step 2: Visually inspect the auxiliary pump connector and wiring for damage, corrosion, or loose connections.
Step 3: Measure the resistance of the pump motor; compare to manufacturer specifications.
Step 4: Test the voltage supply and ground at the pump connector with the engine running and transmission in gear.
Step 5: If wiring and connections are good, replace the auxiliary transmission fluid pump motor.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as low pump current can cause transmission overheating and damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Diagnosis typically costs $50-$150. Replacing the pump motor can range from $200-$600 depending on vehicle and labor rates.