C05AE code meaning
ABS Pump Motor Calibration Not Learned
Chassis system Generic code C05xx codes Check engine light
What C05AE means
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.
C05AE at a glance
- Check engine lightYes, usually on
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyHard
- Typical labor0.3 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of C05AE
- ABS and brake warning lamps plus check engine lamp
- ABS or stability functions limited until the calibration succeeds
Common causes of C05AE
- Most 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
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
ABS pump motorABS module
What each part of C05AE means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| AE | The exact fault in that area. |
What to do next
- Note C05AE 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 C05AE
What does C05AE mean?
C05AE means "ABS Pump Motor Calibration Not Learned". C05AE means the brake module lacks a valid zero calibration for the measuring channels of its pump motor. It is a generic code, so it means the same on every make.
Is it safe to drive with C05AE?
Drive gently and only to a workshop. With C05AE the car can go into limp mode (reduced power) to protect itself.
Will C05AE fail an emissions test?
C05AE is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C05AE to fix?
Difficulty: hard. A typical repair takes 0.3 to 3 hours of work. This is a job for a workshop.
Will C05AE 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.