C1237 on Mercury

Primary brake pressure sensor signal (Hyundai) or rear wheel speed sensor (Ford)

Severity: Inspect soon

Hyundai owners report C1237 with a failed brake hydraulic unit and in one case brake failure and towing; Ford owners report no ABS.

It gets more serious if:

Stop: Stop and have it checked if a red BRAKE warning or "check brake system" message appears, or the pedal feels hard, soft or different.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

This page covers only what differs on Mercury. For what C1237 means, the ranked causes and the test order, see the C1237 guide.

2002–2004 · Mountaineer
Supported by vehicle data
Ford bulletins 14900 and 03263 cover the Mountaineer with C1237 and an ABS light. Only the NHTSA summaries were read.

Ford 14900: ABS light on with C1230 and/or C1237 (2002 Explorer, Mountaineer) — NHTSA manufacturer communications (flat file, NHTSA ID 620216)
Ford 03263: ABS lamp with C1235, C1236, C1237 on vehicles with differential-mounted rear wheel speed sensor (2002-2004 Explorer, Mountaineer, Aviator) — NHTSA manufacturer communications (flat file, NHTSA ID 10008281)
NHTSA complaint ODI 11435765: 2012 Hyundai Sonata C1237 hydraulic power unit — NHTSA Office of Defects Investigation
NHTSA complaint ODI 10142417: 2002 Ford Explorer ABS light and C1237 — NHTSA Office of Defects Investigation

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error