C05A4Wheel Speed Sensors Supply Circuit Low
- Generic OBD-II code · Chassis
- Turns on the check-engine light
- Can trigger limp mode
- How the car detects it
- The shared feed for the active wheel speed sensors is too low for them to work. In GM's hybrid tables of 2016 and 2019 the brake controller measures, via an internal comparator, the voltage between the sensor supply line and the signal line and sets C05A4 below 6.7 V for 0.06 s while system voltage is above 6.9 V, Type A with MIL; it also blocks the single-wheel codes such as C0500–C0504. A 2019 GM EBCM reads the supply through its ASIC, on units without a regulated sensor feed also against the 12 V input, and sets the code within 15 ms. Allegro's sensor IC needs at least 4 V, or 5.2 V for one variant. On the 2021 Jeep Wrangler 4xe a weak 12 V battery set C05A4 together with other low-voltage codes and a MIL; the fix was to charge, test and replace the battery (08-106-21). Check battery and charging before parts.
- What you may notice
- ABS, traction and stability control lamps on, MIL possible
- Several wheel speed codes at once, often with low-voltage codes
- Hard starting or no start when the 12 V battery is the cause
- Likely causes
- LikelyDischarged or failing 12 V battery (FCA 08-106-21)
- PossibleWheel speed sensor wiring shorted to ground, pulling the shared supply down
- RareSensor supply stage inside the brake module failing
- Repair
- Medium · Often possible to do yourself.Typical cost: €0 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.