Chassis, generic

C0237 Loss of Speed Sensor Signal Front Left

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

The publicly available J2012 tables skip C0237. GM lists the number in PIP5094, and AA1Car's GM-based code table reads it as Rear Wheel Speed Signal Erratic, so GM's use concerns the rear axle, not the front left wheel of the title. Other makers code a lost front left signal differently: the Saab 9-5 records an open or shorted front left sensor as C1372 and a mechanical or functional fault as C1371, switching ABS, TCS and ESP off. A total loss means no pulses reach the module although the other wheels turn; typical reasons are a cable torn at the steering knuckle, a sensor pushed away from its 29-tooth ring or a damaged connector. HELLA advises checking supply and signal with a meter and oscilloscope before a new sensor is fitted.

Likely causes

Broken sensor cable or damaged connector at the front left wheel
Sensor failed or pushed out of position after suspension work
Tone ring damaged or missing after drive shaft or hub replacement

Symptoms

  • ABS, traction and stability lamps on
  • No ABS; speedometer may misread if it uses this wheel

Repair estimate

DifficultyMediumDIY possible
Parts and labour€40–300
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

wheel speed sensortone ringabs control modulesensor wiring

Related codes

C0035C0235C0500

References: static.nhtsa.gov, aa1car.com, saabwisonline.com, hella.com.