C1285: OBD-II code C1285 flags an electrical fault in the lateral accelerometer circuit — the EBCM sees an open, shorted, or out-of-range sensor signal.

Symptoms

• ABS, traction control, and stability control warning lamps illuminate together and stay on continuously after every start.
• Stability control interventions are disabled because the EBCM has no valid lateral-acceleration input.
• Standard braking and ABS remain functional; the fault is confined to the electronic stability system.

Common causes

• A failed lateral accelerometer sensor with an open, shorted, or noisy output signal.
• Damaged sensor wiring or a corroded connector between the sensor cluster and the EBCM.
• A failed EBCM sensor input driver that no longer processes the accelerometer signal correctly.

What to do?

Read live lateral-accel data — with the vehicle stationary and level, values should be near zero and stable. If the value is stuck, noisy, or reads out of range, inspect sensor wiring and connectors first, then replace the accelerometer. Perform sensor calibration after any replacement.