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U025E Lost Communication With Electronic Brake Booster Control Module A

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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.

Likely causes

Damaged CAN wiring or connector between engine or brake controllers and the booster unit
Fault in the booster's power supply (high-current fuse, ground, 12 V battery)
Internal failure of the electric brake unit
Failure of the receiving engine control module

Symptoms

  • Check engine lamp after repeated detection (Mitsubishi)
  • Brake, ABS or stability warning lamps on
  • Harder brake pedal or reduced regenerative braking

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–2,000
Time0.5–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

electronic brake booster module avehicle bus wiring

Related codes

U055FU025FU034BU0121

References: mitsubishitechinfo.com, mitsubishitechinfo.com, mitsubishitechinfo.com, bosch-mobility.com.