Chassis, generic

C055B ABS Pump Motor Supply Voltage Circuit A Low

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

Supply voltage A of the pump motor is below its lower limit. Under load the motor pulls the feed down, so a weak 12 V battery, a corroded terminal, a high-resistance fusible link or a poor ground can all set it, and the relay may chatter. No maker publishes C055B. On the 2023 Outlander PHEV Mitsubishi specifies 10–16 V at the motor feed and flags an ignition supply of 10 V or less at its brake unit within 1 s under C1056-16, a code without generic equivalent. A patent originally filed by AlliedSignal and now owned by Bosch flags its own fault if the motor sits under roughly 7 V at shut-off, and a Hitachi patent for electric brake actuators limits motor current once the vehicle supply falls under a set level. Charge and test the battery before replacing parts.

Likely causes

Weak or discharged 12 V battery
Corroded terminal or high-resistance fusible link in the motor feed
Poor ground connection of the ABS unit

Symptoms

  • ABS and ESC warning lamps on, often after cold starts
  • Pump runs sluggishly or ABS functions drop out

Repair estimate

DifficultyEasyDIY possible
Parts and labour€0–300
Time0.2–1.5 h

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

Parts involved

abs pump motor supply a

Related codes

C055AC055CC052FC05A7

References: mitsubishitechinfo.com, mitsubishitechinfo.com, patents.google.com, patents.google.com.