U0112 code meaning
Lost Communication With Battery Energy Control Module B
Network system Generic code U01xx codes Check engine light
What U0112 means
U0112 is logged when a second battery energy control module, B, stops talking on the bus while a partner still waits for its data. Mitsubishi's 2018 Outlander PHEV is a documented case: the main battery management unit (BMU) supervises a sub-BMU inside the traction pack and stores U0112 once that unit's frames have been missing for 0.3 s, after the BMU has seen 8–16 V for more than 2 s; the check follows drive-cycle pattern 1, and the CAN pair between the two units should measure 100–140 Ω. VW's 2014 Touareg Hybrid lists the code for absent BECM messages, and GM's Saab 9-4X list assigns it to its battery module. Module A has U0111. Typical results are a hybrid warning, less electric range or no READY.
U0112 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor1 to 6 hours
- Clears after repairAfter a drive cycle
Symptoms of U0112
- MIL or hybrid system warning
- Reduced electric range or electric drive unavailable
- Vehicle does not reach READY
Common causes of U0112
- Most likelyOpen, shorted or chafed CAN lines between main and sub battery module inside the pack
- PossibleCorroded or loose connector at the traction battery
- PossibleBattery module B internally faulty or without supply
- Less likelyReceiving main battery module faulty
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Battery energy control moduleCAN bus wiring
What each part of U0112 means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 12 | The exact fault in that area. |
What to do next
- Note U0112 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 U0112
What does U0112 mean?
U0112 means "Lost Communication With Battery Energy Control Module B". U0112 is logged when a second battery energy control module, B, stops talking on the bus while a partner still waits for its data. It is a generic code, so it means the same on every make.
Is it safe to drive with U0112?
Drive gently and only to a workshop. With U0112 the car can go into limp mode (reduced power) to protect itself.
Will U0112 fail an emissions test?
Yes, it can. U0112 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 U0112 to fix?
Difficulty: workshop only. A typical repair takes 1 to 6 hours of work. This is a job for a workshop.
Will U0112 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.