A fault code doesn’t yet mean the unit or sensor itself is faulty: often it’s the plug and connector leading to it.
Possible causes
- The sensor connector: dirt, water, corroded pins
- The wheel sensor harness: chafed or shorted
- ABS control unit
What you can do yourself
- With this fault ABS usually switches off: the ordinary brakes still work, but without ABS the wheels can lock. Brake smoothly and leave a bigger gap, especially on slippery roads.
- Inspect the sensor harness near the radiator and under the headlight: per a Kia bulletin (Optima 2015) it chafes on a bracket.
- A scan tool’s live data shows each wheel’s speed: while driving, this wheel should read the same as the others.
Stop and don’t drive on if:
- The red brake light is on, or the brake pedal feels soft or sinks
- The steering became very heavy, or the car pulls to one side when braking
OOleg’s tip: check the connector
Often the cause is simple — there is no contact in the connector (plug). Look at the connector from the back: remove the rubber seal and you will see whether a wire is corroded or has come off completely. Corrosion shows up as green deposits. Ideally, gently pull each wire towards you one at a time: a sound wire stays in place, while a corroded one simply comes off — it needs to be repaired.
Unplug and inspect connectors with the ignition off.
ESC is the Hyundai and Kia stability control system (the same as ESP). This is the Hyundai and Kia meaning. On other makes this number means something else: if your car isn’t a Hyundai or Kia, change the make at the top.
Source: Kia TT066 (Optima 2015), static.nhtsa.gov
The explanation comes from the error code reference in the AvtoElektrik PRO app.