U02AELost Communication With Hybrid/EV Battery Coolant Pump
- Generic OBD-II code · Network
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- The battery coolant pump circulates coolant through the high-voltage pack. Electrically commutated pumps like Bosch's PAD2 carry their own electronics, take a speed request by PWM or LIN and report back. U02AE applies when such a pump is a bus node and stops answering the controller that runs battery thermal management. No manufacturer documents U02AE publicly. Pumps driven over a plain control line report P0C47 and its siblings instead: GM's 2019 hybrid table checks the HV battery pump line for under 200 mA or over 3 A while on, Type B. Under CARB 1968.2, every electronic input and output used to heat or cool the high-voltage battery must be monitored. Without the pump the pack warms faster, so charge and drive power may be limited. U0694 and U0695 name pumps A and B.
- What you may notice
- Hybrid or battery warning, possibly with the MIL
- Reduced charging rate or electric drive power, especially when hot
- Battery temperature rises faster than usual
- Likely causes
- LikelyMoisture or corrosion in the pump connector, pushed-out terminal
- PossiblePump electronics failed (seized rotor, internal fault)
- PossibleLIN/bus wire, supply fuse or ground of the pump interrupted
- RareSoftware fault in the battery or thermal management controller
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €50 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.