OBD-II code · Network
U01A9 Lost Communication With Hybrid/EV Battery Interface Control Module J
ECU lost CAN communication with hybrid/EV HV battery interface module J (BMS slave or cell-monitoring submodule).
Is it safe to drive with U01A9?
The car may go into limp mode (reduced power). Get it diagnosed before a long trip.
Common causes
- Most likelyModule unpowered
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
Symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Repair at a glance
- Difficulty
- Hard
- DIY friendly
- Best left to a mechanic
- Typical labour
- 1–8 h
- Emissions test
- Usually unaffected
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Hv Battery Interface J, Can Bus
Related codes
- U01A3Lost Communication With Hybrid/EV Battery Interface Control Module D
- U01A4Lost Communication With Hybrid/EV Battery Interface Control Module E
- U01A5Lost Communication With Hybrid/EV Battery Interface Control Module F
- U01A6Lost Communication With Hybrid/EV Battery Interface Control Module G
- U01A7Lost Communication With Hybrid/EV Battery Interface Control Module H
- U01A8Lost Communication With Hybrid/EV Battery Interface Control Module I
- U01AALost Communication With Hybrid/EV Battery Interface Control Module K
- U01ABLost Communication With Hybrid/EV Battery Interface Control Module L
- U01ACLost Communication With Hybrid/EV Battery Interface Control Module M
- U01ADLost Communication With Hybrid/EV Battery Interface Control Module N
- U01AELost Communication With Hybrid/EV Battery Interface Control Module O
- U01AFLost Communication With Hybrid/EV Battery Interface Control Module P
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.