U01A5 code meaning
Lost Communication With Hybrid/EV Battery Interface Control Module F
Network system Generic code U01xx codes Check engine light
What U01A5 means
U01A5 says the battery controller no longer receives data from interface module F. Once such a board drops out, the cells it covers are unsupervised: no voltage readings, no temperatures and no balancing for that section. GM therefore puts all of these codes into a fault bundle called BICM Loss of Comm in its 2018 hybrid table, which blocks battery diagnostics that would otherwise misfire on missing values. On the road the controller shields the pack, so reduced power, refused charging or opened contactors are to be expected. Audi bulletin 2078135 for the 2016 A3 Sportback e-tron describes a drive system that cannot be activated and a red warning lamp, with U01A500 among the A-H codes plus P0AA500 and P0A7D00. GM monitors F as Type A from 2016 to 2019.
U01A5 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 8 hours
- Clears after repairWhen cleared with a scanner
Symptoms of U01A5
- Drive system cannot be activated, red warning lamp
- Charging refused or stopped early
- Other battery diagnostics suspended while the code is active
Common causes of U01A5
- Most likelyChain connection between module E and module F interrupted
- PossibleBattery interface control module F defective
- Less likelyBoard F loses supply because its cell group or sense tap is open
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hv battery interface module fCommunication bus
What each part of U01A5 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| A5 | The exact fault in that area. |
What to do next
- Note U01A5 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 U01A5
What does U01A5 mean?
U01A5 means "Lost Communication With Hybrid/EV Battery Interface Control Module F". U01A5 says the battery controller no longer receives data from interface module F. It is a generic code, so it means the same on every make.
Is it safe to drive with U01A5?
Drive gently and only to a workshop. With U01A5 the car can go into limp mode (reduced power) to protect itself.
Will U01A5 fail an emissions test?
Yes, it can. U01A5 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 U01A5 to fix?
Difficulty: workshop only. A typical repair takes 1 to 8 hours of work. This is a job for a workshop.
Will U01A5 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.