C1287: OBD-II code C1287 flags an implausible steering angle rate-of-change — the sensor is reporting movement faster than any human input could produce.

Symptoms

• ABS and stability control warning lamps illuminate together and remain on continuously after start.
• Stability control interventions are disabled because the EBCM cannot trust the rate-of-change of the steering signal.
• Standard driving feels normal; the fault only shows up in scan data or by way of the illuminated ESC lamp.

Common causes

• A failing steering angle sensor with intermittent signal spikes or dropouts producing implausible rate values.
• A poor sensor ground or noisy power supply feeding the sensor and corrupting its output.
• EMI/RFI interference on the sensor signal wires, often caused by proximity to aftermarket wiring or a failed alternator.

What to do?

Monitor live steering-angle data during a slow steering sweep — signal should be smooth and continuous. Inspect the sensor's connector, ground, and shielded wiring for damage. If the sensor exhibits spikes, replace it and recalibrate. Look for and remove sources of EMI.