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 suggests the motor is not operating properly, which can lead to inadequate fluid circulation, overheating, and potential transmission damage.
1. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission overheating or slipping
- Reduced fuel economy
- Transmission warning message on dashboard
2. Most Common Causes
- Faulty auxiliary transmission fluid pump motor
- Open or shorted wiring in the pump circuit
- Blown fuse or relay for the pump
- Failed PCM (rare)
3. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect the auxiliary pump fuse and relay; replace if blown.
Step 3: Check wiring and connectors for damage, corrosion, or loose connections.
Step 4: Test pump motor resistance and current draw with a multimeter; compare to specs.
Step 5: If pump is faulty, replace it and clear codes.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended. Low pump current can cause transmission overheating and damage. Have it diagnosed and repaired promptly.
How much does it cost to fix?▼
Typical repair costs range from $200 to $600, including parts and labor. The pump itself is often $100-$300, plus diagnostic time.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.