OBD-II reference

All 9.533 generic OBD-II codes, explained in detail.

Causes, inspection steps and sources — a comprehensive DIY archive. Created and maintained with love for the detail. Good luck and have fun!

Chassis generic / SAE

C0161

ABS/TCS Brake Switch Circuit

The ABS or traction control module has detected an implausible signal from the brake light switch. The switch tells the module whether the driver is braking and is used to inhibit traction control during braking.

SystemChassis
Typegeneric / SAE
GroupC0
Range / number1 / 61

Possible causes

  • Brake light switch failed or misadjusted high
  • Wiring or connector fault medium

Symptoms

  • ABS warning light on
  • ESC/stability control deactivated
  • Possible reduced brake assist
  • Speedometer may behave erratically

Inspection / repair

  • Difficulty: easy
  • DIY: possible
  • Estimated cost: 30–200 €
  • Estimated time: 0.3–1 h
  • Component: brake light switch
  • Component: abs control module
  • Component: tcs control module

Sources

References

How to read OBD-II codes

The first letter names the vehicle system, the second digit distinguishes generic from manufacturer-specific, the remaining digits group fault area and number.

PPowertrain: engine, transmission, emissions
BBody: chassis trim, comfort, interior
CChassis: suspension, brakes, steering
UNetwork: CAN, control modules, communication