Auxiliary Transmission Fluid Pump Motor Current High
The P0C28 code indicates that the Engine Control Module (ECM) or Transmission Control Module (TCM) has detected an abnormally high current draw from the auxiliary transmission fluid pump motor. This pump is responsible for circulating transmission fluid to maintain lubrication and cooling, especially during start-stop events or when the engine is off. High current can be caused by a failing pump motor, electrical short, or mechanical binding, potentially leading to transmission damage if not addressed.
01. Most Common Causes
- Faulty auxiliary transmission fluid pump motor
- Short circuit in pump motor wiring or connector
- Mechanical binding or seized pump
- Low transmission fluid level causing pump to work harder
- Failed pump relay or control module
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission overheating or slipping
- Reduced fuel economy due to start-stop system disabled
- Unusual noise from transmission area
- Transmission warning message on dashboard
03. Step-by-Step Diagnosis
Step 1: Scan for additional codes and check freeze frame data.
Step 2: Inspect transmission fluid level and condition; top up if low.
Step 3: Visually check pump motor wiring and connector for damage or corrosion.
Step 4: Measure pump motor resistance and compare to specifications; replace if out of range.
Step 5: Test pump relay and control circuit for proper voltage and ground.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
Driving with P0C28 is not recommended as it can lead to transmission overheating and damage. Have the vehicle inspected promptly.
How much does it cost to fix?▼
Repair costs typically range from $200 to $600, depending on whether the pump motor or electrical components need replacement. Labor and parts vary by vehicle.