U0694 code meaning
Lost Communication With Hybrid/EV Battery Pack Coolant Pump A
Network system Generic code U06xx codes Check engine light
What U0694 means
Liquid-cooled traction batteries rely on an electric pump to move coolant through the pack, and pumps like Bosch's PCE accept their speed command by PWM or LIN and report faults themselves. U0694 records that battery pump A no longer communicates. Published manufacturer data do not mention it. GM's hybrid table 19OBDG01 drives its battery pump by a discrete or PWM line and judges the line current (under 200 mA or over 3 A, 4 s within 5 s, Type B), so faults surface as P0C47. Hyundai uses its own U1118 for the battery pump on the 2019 Kona Electric; campaign T4G traced it to coolant entering the pump's electronics housing and replaces the housing or the pump. Expect reduced power, slower charging and a hybrid or EV warning.
U0694 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyHard
- Typical labor1 to 4 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U0694
- Hybrid/EV system warning
- Reduced drive power
- Slower DC fast charging
Common causes of U0694
- Most likelyCoolant entered the pump electronics housing
- PossibleBus, supply or ground wire to the pump damaged
- PossiblePump motor or controller failed
- Less likelyBattery or hybrid controller software fault
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery coolant pump aVehicle bus wiring
What each part of U0694 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 94 | The exact fault in that area. |
What to do next
- Note U0694 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 U0694
What does U0694 mean?
U0694 means "Lost Communication With Hybrid/EV Battery Pack Coolant Pump A". Liquid-cooled traction batteries rely on an electric pump to move coolant through the pack, and pumps like Bosch's PCE accept their speed command by PWM or LIN and report faults themselves. It is a generic code, so it means the same on every make.
Is it safe to drive with U0694?
Drive gently and only to a workshop. With U0694 the car can go into limp mode (reduced power) to protect itself.
Will U0694 fail an emissions test?
Yes, it can. U0694 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 U0694 to fix?
Difficulty: hard. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will U0694 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.