System Pre Check

Connector Diagram:

DESCRIPTION
Code 12 is generated when the anti-lock electronic control module detects that the brake fluid level in the brake master cylinder reservoir (2K478) is low for one or more seconds. It can also be generated by a short in the stoplight circuit.

POSSIBLE CONTRIBUTING BASE BRAKE COMPONENT/VEHICLE WIRING CONCERNS
- Low brake master cylinder fill level
- Brake fluid leaks in vehicle brake system
- Worn or damaged master cylinder brake fluid level switch, or brake fluid level circuit shorted to ground
- Brake master cylinder reservoir float that sticks in the bottom of brake master cylinder reservoir or does not float
- Failed diode-resistor element in stoplight circuit
- Damaged ignition switch
- Ground short in Circuits 512 (T/LG) or 531 (DG/Y)
- Damaged anti-lock electronic control module

NOTE: Use Rotunda(r) 73 Digital Multimeter 105-00051 or equivalent for electrical tests.