C0237 code meaning
Loss of Speed Sensor Signal Front Left
What C0237 means
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.
C0237 at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 2 hours
- Clears after repairAfter a drive cycle
Symptoms of C0237
- ABS, traction and stability lamps on
- No ABS; speedometer may misread if it uses this wheel
Common causes of C0237
- Most likelyBroken sensor cable or damaged connector at the front left wheel
- PossibleSensor failed or pushed out of position after suspension work
- Less likelyTone ring damaged or missing after drive shaft or hub replacement
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Wheel speed sensorTone ringABS control moduleSensor wiring
What each part of C0237 means
| C | Chassis system: brakes, ABS, steering and suspension. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 37 | The exact fault in that area. |
What to do next
- Note C0237 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about C0237
What does C0237 mean?
C0237 means "Loss of Speed Sensor Signal Front Left". The publicly available J2012 tables skip C0237. It is a generic code, so it means the same on every make.
Is it safe to drive with C0237?
Drive gently and only to a workshop. With C0237 the car can go into limp mode (reduced power) to protect itself.
Will C0237 fail an emissions test?
C0237 is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is C0237 to fix?
Difficulty: medium. A typical repair takes 0.5 to 2 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will C0237 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.