Chassis, generic

C0238 Speed Wheel-to-Wheel Mismatch

Check engine lightUsually off
EmissionsNot relevant
Drive cycleRequired
Limp modePossible

C0238 does not appear in the publicly available J2012 code lists. GM uses it: the terminal-check bulletin PIP5094 for 2014 and older GM cars and light trucks names it as a chassis keyword, and AA1Car's table of GM ABS codes calls it Wheel Speed Mismatch, which fits the title. GM does not publish its setting rule for this number. A related GM test on the 2011 Saab 9-5 shows the principle: above 14 km/h, brake off and driving straight, a wheel reading more than 20 percent off the others is treated as a fault. Typical reasons are one tyre of a different size or pressure, a spare wheel, a damaged tone ring or a sensor with too much air gap. ABS and traction control are normally switched off until the next ignition cycle.

Likely causes

One tyre with different size, wear or pressure, or a space-saver spare fitted
Cracked, corroded or wrong tone ring on one wheel
Wheel speed sensor loose or with excessive air gap, or worn wheel bearing

Symptoms

  • ABS and traction control warning lamps on
  • ABS and traction control disabled for the rest of the trip

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 ringtiresabs control module

Related codes

C0245C0234C0035C0040

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