C05AE

Code

Generic C — Chassis

ABS Pump Motor Calibration Not Learned

Brand: Generic

Type: C — Chassis

Views: UK: 17 EN: 34 RU: 20

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

ABS pump motor calibration procedure not performed after repair or battery disconnect
Low or unstable battery/system voltage during learn
Blown fuse or bad relay for ABS pump motor power
Poor electrical connection (corroded connector, broken wire, bad ground)
Faulty ABS pump motor or hydraulic unit
Faulty ABS control module (motor driver) or corrupted software

Symptoms

ABS warning lamp illuminated (may be steady or flashing)
Traction control/ESC warning lights may also be on
ABS pump may not activate when ABS event occurs
Brake pedal feel may be altered under ABS events (reduced ABS function)
DTC returns after clearing or after battery disconnect/repair
Quieter or abnormal pump motor noise, or no pump noise when commanded

What to check

Read ABS module freeze-frame and related stored codes with a capable scan tool
Verify vehicle battery voltage is within specification (>12.4 V steady) and battery is fully charged
Inspect ABS pump fuses, relays and harness connectors at ABS hydraulic unit for corrosion or loose pins
Check for related chassis/ABS codes (wheel speed, steering angle, comms) that could block learn
Attempt the manufacturer-recommended ABS pump calibration/learn using OEM scan tool and record results
Monitor live data during calibration: pump motor command, motor current, PWM duty, pump speed feedback, wheel speed sensors, CAN/BUS status

Signal parameters

Supply voltage to pump motor: typically ~12–14.5 V during operation (should not drop excessively during learn)
Motor current draw: nominal low when free-running; elevated or locked-stall current indicates mechanical or electrical fault (vehicle-specific limits)
PWM duty cycle: 0–100% as commanded by ABS module during calibration
Pump speed or flow feedback (if available): should change in response to commands
Wheel speed sensor signals: valid and present on all wheels during learning
CAN/CAN-FD or LIN comms: ABS module should be communicating with other modules

Diagnostic algorithm

Verify the DTC C05AE is current and capture freeze-frame data and any related codes.
Ensure battery is fully charged and stable. Recheck battery terminals and ground connections; charge or replace battery if voltage is low.
Visually inspect fuses, relays and connectors at the ABS hydraulic unit and clean/repair any corrosion or damage.
Use an OEM-capable scan tool and follow the factory ABS pump motor calibration/learn procedure exactly. Attempt the learn with good battery voltage and record results.
While performing learn, monitor live data: command to pump motor, PWM duty, motor current, and any pump feedback. Note deviations (no command, no motor response, excessive current, no feedback).
If motor receives command but does not run: test power and ground at pump motor connector with key on and while commanded. Check for open circuit, short to battery, or poor ground. Replace wiring/connector as needed.
If motor runs but calibration fails: confirm wheel speed sensors and steering angle sensor are producing valid signals. Repair any sensor faults and retry learn.
If motor draws excessive current or is noisy: remove and bench-test or replace the ABS pump/hydraulic unit. Inspect for internal mechanical seizure or hydraulic blockage.
If electrical tests pass and motor/hydraulic unit bench tests OK but calibration still fails: consider ABS module software/firmware update or replace module per OEM guidance.
After repair or module replacement, clear codes, repeat learn, perform ABS system bleed if hydraulic work was done, then road test to confirm no recurrence.