U025E code meaning
Lost Communication With Electronic Brake Booster Control Module A
Network system Generic code U02xx codes Check engine light
What U025E means
Instead of a vacuum servo, an electronic brake booster uses a pedal travel sensor and an electric motor for the assist, which also lets regenerative braking be blended in, as in Bosch's iBooster. Mitsubishi documents U025E-00 in the engine control module of the Outlander PHEV from 2023, where it means lost contact with the EBA, the electric driven intelligent brake unit. With the power switch on and 10 to 16.5 V, no brake unit signals for 4 s set the code; it is stored when the fault recurs after the next start and belongs to the CAN monitor of the OBD drive cycle, which covers faults that light the check engine lamp. PHEV-ECU and ABS unit log their own timeouts. Ford shows the knock-on effect: a supply interruption at its booster lit the ABS and stability lamps (SSM 51374). Unit B is U025F.
U025E at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyWorkshop only
- Typical labor0.5 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of U025E
- Check engine lamp after repeated detection (Mitsubishi)
- Brake, ABS or stability warning lamps on
- Harder brake pedal or reduced regenerative braking
Common causes of U025E
- Most likelyDamaged CAN wiring or connector between engine or brake controllers and the booster unit
- PossibleFault in the booster's power supply (high-current fuse, ground, 12 V battery)
- PossibleInternal failure of the electric brake unit
- Less likelyFailure of the receiving engine control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Electronic brake booster module aVehicle bus wiring
What each part of U025E means
| U | Network system: communication between the control modules (CAN bus). |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 5E | The exact fault in that area. |
What to do next
- Note U025E 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 U025E
What does U025E mean?
U025E means "Lost Communication With Electronic Brake Booster Control Module A". Instead of a vacuum servo, an electronic brake booster uses a pedal travel sensor and an electric motor for the assist, which also lets regenerative braking be blended in, as in Bosch's iBooster. It is a generic code, so it means the same on every make.
Is it safe to drive with U025E?
Drive gently and only to a workshop. With U025E the car can go into limp mode (reduced power) to protect itself.
Will U025E fail an emissions test?
Yes, it can. U025E 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 U025E to fix?
Difficulty: workshop only. A typical repair takes 0.5 to 4 hours of work. This is a job for a workshop.
Will U025E 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.