Chassis, generic

C0245 Wheel Speed Sensor Frequency Mismatch

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

C0245 is missing from the reachable J2012 lists but is a documented GM code: PIP5094 lists it, AA1Car's GM table names it Wheel Speed Sensor Frequency Error, and the 2010 and 2011 Saab 9-5 manuals call it Wheel Speed Sensor Frequency Malfunction. The active sensors there get 12 V from the brake module and return a square wave whose frequency gives the wheel speed. The check runs above 9 mph with no open-circuit sensor code, brake released and no cornering; if one wheel differs from the rest by more than 20 percent, ABS, hill start assist, traction and stability control shut down for that ignition cycle and three warning lamps light. GM first checks tyre size and pressure, then the tone ring and sensor seating.

Likely causes

Tyre with wrong size or pressure on one wheel
Damaged or contaminated tone ring or magnetic encoder
Sensor not seated correctly or excessive wheel bearing play

Symptoms

  • ABS, traction/stability and brake warning lamps on together
  • ABS, stability control and hill start assist disabled

Repair estimate

DifficultyMediumDIY possible
Parts and labour€0–400
Time0.2–2 h

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

Parts involved

wheel speed sensortone ringabs control module

Related codes

C0238C0234C0035C0050

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