Fault code lookup

ChassisC120B

Caution

Severity: Caution - get it checked when you can

Relay does not close

5 brands affected · Description from Toyota data.

Key terms: ABS: anti-lock braking, which stops the wheels locking · Stability control: helps stop the car skidding · Wheel speed sensor: measures how fast each wheel turns

1What it means in plain English

A chassis system has a fault, usually ABS, traction control or stability control, but some makes use this range for airbags, electric power steering or park brakes.

2Common causes

  1. Faulty wheel speed sensor
  2. Damaged sensor ring or wiring
  3. Faulty ABS module
  4. Low brake fluid
  5. Wheel bearing damage

3Can I drive?

Caution · drive with care

If the code names an airbag or SRS system, the airbag may not deploy in a crash: have it diagnosed promptly. If it names electric power steering, the assist may fail and the steering can become heavy: stop safely if that happens. If it names the brakes or park brake, have it checked before driving when braking feels abnormal. Otherwise ABS and stability control may be disabled: drive carefully, especially in wet conditions, and have it checked soon.

This page gives general information. It is not professional advice. For a definite diagnosis and a repair quote, ask a qualified mechanic to inspect the car.

4Brand data 5

BrandCodeDescriptionSystem
CheryC120BRotor position sensor secondary channel fault BrandChassis
DFFSC120BRelay does not close BrandChassis
HyundaiC120BNo description available Chassis
PeugeotC120BNo description available Chassis
ToyotaC120BRelay does not close BrandChassis

Legend: SAE is the generic J2012 description; Brand is text taken from that manufacturer’s data. Manufacturer rows keep the wording and language of the source data, and non-English text is tagged so screen readers pronounce it correctly.

5Extended variant codes 2

These 7-character codes are manufacturer-specific variants of C120B and may be reported by some scan tools.

BrandCodeDescriptionSystem
HyundaiC120B15In case of LED right short to battery or open, is set to active BrandChassis
SsangYongC120B15Right offside mirror indicator lamp circuit open or short to battery (+) BrandChassis

6Related codes

Browse Cxxx codes or C120xx codes.

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