C1237 on Hyundai

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 Hyundai. For what C1237 means, the ranked causes and the test order, see the C1237 guide.

What's different on Hyundai

Hyundai

2009–2014 · Sonata
Supported by vehicle data
Sonata owners quote C1237 as the primary pressure sensor signal. Based on owner complaints.

Sources and review

NHTSA complaint ODI 11301374: 2009 Hyundai Sonata HECU failure with C1237 — NHTSA Office of Defects Investigation
NHTSA complaint ODI 11435765: 2012 Hyundai Sonata C1237 hydraulic power unit — NHTSA Office of Defects Investigation
NHTSA complaint ODI 11557250: 2012 Hyundai Sonata Hybrid C1237 and P1886 — NHTSA Office of Defects Investigation
NHTSA complaint ODI 10142417: 2002 Ford Explorer ABS light and C1237 — NHTSA Office of Defects Investigation

Last reviewed: October 15, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

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