U02AE code meaning
Lost Communication With Hybrid/EV Battery Coolant Pump
Network system Generic code U02xx codes Check engine light
What U02AE means
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.
U02AE at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of U02AE
- Hybrid or battery warning, possibly with the MIL
- Reduced charging rate or electric drive power, especially when hot
- Battery temperature rises faster than usual
Common causes of U02AE
- Most 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
- Less likelySoftware fault in the battery or thermal management controller
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery coolant pumpVehicle bus wiring
What each part of U02AE means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| AE | The exact fault in that area. |
What to do next
- Note U02AE and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about U02AE
What does U02AE mean?
U02AE means "Lost Communication With Hybrid/EV Battery Coolant Pump". The battery coolant pump circulates coolant through the high-voltage pack. It is a generic code, so it means the same on every make.
Is it safe to drive with U02AE?
Drive gently and only to a workshop. With U02AE the car can go into limp mode (reduced power) to protect itself.
Will U02AE fail an emissions test?
Yes, it can. U02AE is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is U02AE to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will U02AE clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.