Auxiliary Transmission Fluid Pump Motor Phase U Current High
The P0B02 code indicates that the Powertrain Control Module (PCM) has detected an abnormally high current draw on phase U of 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. High current can be caused by a short circuit, a failing motor, or a stuck pump, potentially leading to transmission overheating or damage.
01. Most Common Causes
- Short circuit in the pump motor windings or wiring
- Failing auxiliary transmission fluid pump motor
- Mechanical binding or seized pump
- Faulty PCM or wiring issue
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Transmission overheating or slipping
- Reduced fuel economy
- Transmission warning messages on dashboard
03. Step-by-Step Diagnosis
Step 1: Scan for codes and record freeze frame data.
Step 2: Inspect wiring and connectors for damage, corrosion, or shorts.
Step 3: Test pump motor resistance and current draw using a multimeter.
Step 4: Check for mechanical binding by manually rotating the pump (if accessible).
Step 5: Replace pump if electrical or mechanical fault is confirmed.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
No, driving with high current draw can damage the pump or transmission. Have it inspected immediately.
How much does it cost to fix?▼
Typically $150-$400 for parts and labor, depending on vehicle and pump accessibility.