C1225: OBD-II code C1225 flags an erratic left front wheel speed signal — the EBCM sees brief drops or spikes and disables ABS intermittently.

Symptoms

• The ABS and traction control warning lamps illuminate intermittently, usually only while driving, and may clear after an ignition cycle before returning.
• The ABS can activate at low speeds when it shouldn't, or feel erratic, and the brake pedal may pulse unexpectedly during light braking.
• Stability control interventions can trigger inappropriately, which some drivers feel as a brief pull or momentary brake drag.

Common causes

• Missing teeth or damage on the left front reluctor or tone ring create momentary dropouts as the sensor rotates past the damaged section.
• Excessive lateral play in the left front wheel bearing lets the sensor gap vary during cornering, causing signal amplitude variation.
• A partially failing sensor producing a noisy signal, metallic debris stuck to the sensor tip, or mismatched tire sizes across the axle can also trigger it.

What to do?

Compare all four wheel speeds in live data during a road test — the errant wheel will show brief drops or spikes while the others read steadily. Inspect the reluctor or tone ring visually for chipped teeth. Check the wheel bearing for play. Clean any metallic debris off the sensor tip. Replace the sensor, hub, or tone ring depending on findings, and confirm tire sizes match across the axle.