C0237 GMC Code - Erratic Rear Speed Signal

C0237 indicates an "Erratic Rear Speed Signal," meaning the vehicle's electronic control module (ECM) is detecting irregular or inconsistent signals from the rear wheel speed sensor.

Symptoms may include the ABS or traction control warning light turning on, reduced ABS or traction control functionality, erratic speedometer readings, or braking issues.

Common causes include a faulty rear wheel speed sensor, damaged or corroded wiring or connectors, a malfunctioning ABS module, or debris interfering with the sensor signal.

While the vehicle may still be drivable, ignoring the code can lead to compromised ABS and traction control performance, increasing the risk of accidents in slippery conditions.

Start by scanning the vehicle with an OBDII scanner to confirm the code. Then inspect the rear wheel speed sensor, wiring, and connectors for damage, debris, or corrosion. Test the sensor signal with a multimeter if necessary.

Repairs typically involve cleaning or replacing the rear wheel speed sensor, repairing damaged wiring, or replacing corroded connectors. In rare cases, the ABS module may need replacement.

You may need an OBDII scanner, a multimeter, basic hand tools (like a socket set), and possibly a replacement speed sensor or wiring repair kit.

Repair costs vary but typically range from $100 to $300 for parts and labor if replacing the speed sensor or repairing wiring. ABS module replacement may be more expensive.

Yes, dirt, debris, or rust on the wheel speed sensor or sensor ring can interfere with signal accuracy and trigger the C0237 code.

Clearing the code without addressing the root cause may temporarily turn off the warning light, but the issue will likely return and compromise vehicle safety. Always fix the underlying problem first.