Auxiliary Transmission Fluid Pump Phase U-V-W Circuit High
The P0C22 code indicates that the Powertrain Control Module (PCM) has detected a high voltage condition in the phase U-V-W circuit of the auxiliary transmission fluid pump. This pump is responsible for circulating transmission fluid to cool and lubricate the transmission, especially during start-stop events or low-speed operation. A high voltage reading suggests a short to power, a faulty pump motor, or a wiring issue, which can lead to inadequate fluid circulation and potential transmission damage.
01. Most Common Causes
- Short to battery voltage in the pump motor circuit
- Faulty auxiliary transmission fluid pump motor
- Damaged wiring or connectors in the pump circuit
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission overheating or slipping
- Reduced fuel economy
- Transmission warning message on dashboard
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 wiring and connectors for damage, corrosion, or shorts.
Step 3: Measure voltage at the pump connector with the ignition on; compare to manufacturer specifications.
Step 4: Test the pump motor resistance and check for shorts to ground or power.
Step 5: If wiring and pump are okay, check PCM for faults and reprogram if necessary.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with this code can cause transmission overheating and damage. It is recommended to have the vehicle towed to a repair shop.
How much does it cost to fix?▼
Repair costs typically range from $200 to $600, depending on whether the pump or wiring needs replacement and labor rates.