C05AEABS Pump Motor Calibration Not Learned
- Generic OBD-II code · Chassis
- Turns on the check-engine light
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- C05AE means the brake module lacks a valid zero calibration for the measuring channels of its pump motor. In GM's 2016 and 2019 hybrid brake module (BSC1) the motor voltages are read through a sigma-delta modulator that needs a 0 V calibration; with the ignition on, more than 6.9 V system voltage and the pump off, the code sets if the raw generator voltage reading falls outside 14–23.8 or the drop across the pump relay outside 13–18, for 3 s. A second test flags supply undervoltage: shunt voltage under 7.5 V or relay drain voltage outside 1.5–3 V for 2 s. Type A with MIL; the check passes after 20 s of driving above 18.6 mph. Such offset calibration is standard for delta-sigma converters, as TI's ADS131M04 data sheet shows.
- What you may notice
- ABS and brake warning lamps plus check engine lamp
- ABS or stability functions limited until the calibration succeeds
- Likely causes
- LikelyStored zero calibration missing or invalid after module replacement or programming
- PossibleLow or unstable supply voltage during the calibration
- PossiblePump motor relay or shunt in the module out of tolerance
- Repair
- Hard · Usually a job for a workshop.Typical cost: €50 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.