ABS warning light on
Yellow ABS lamp stays lit with engine running. ABS is disabled but base brakes still work.
R107 1987 has Bosch 2U ABS — wheel-speed sensors at each front wheel and a single sensor at the rear differential. The control unit is in the trunk.
What the diagnosis checks
- Did the light come on after a wheel-bearing or brake job?
- Pull ABS codes from the diagnostic socket — any wheel-speed faults?
Possible causes it points to
- ABS sensor air gap
- Failed wheel-speed sensor
- ABS control unit / hydraulic
Parts for this job
Brake serviceLoading the step-by-step diagnosis…