Test G: DTC C1187 - Brake Fluid Level Input Circuit Open

Pinpoint Test G: DTC C1187 - Brake Fluid Level Input Circuit Open
Refer to Vehicle/Diagrams, Vehicle Dynamic Systems for schematic and connector information.

Normal Operation
The brake fluid level switch is a normally open switch attached to a flotation device in the master cylinder reservoir. The ABS module sends out a voltage along circuit CMC19 (GY/VT) which returns to the module along circuit RCM19 (YE/GY). When the brake fluid is at the correct level, the switch remains open and the ABS module detects a returning voltage. When the fluid level falls below a predetermined level, the switch closes and connects circuit CMC19 (GY/VT) and circuit RCM19 (YE/GY) to ground circuit GD121 (BK/YE). The ABS module will no longer detect the returning voltage and sends a signal to the instrument cluster along circuit CCA02 (GN/VT) and the instrument cluster illuminates the red brake warning indicator.
^ DTC C1187 Brake Fluid Level Input Circuit Open - If, during normal operation or the ABS module on-demand self test, the ABS module detects and open circuit or a short to ground on circuit CMC19 (GY/VT) or RMC19 (YE/GY), DTC C1187 will be set.

This pinpoint test is intended to diagnose the following:
^ Wiring, terminals or connectors
^ Brake fluid level switch (integral to the brake fluid reservoir)
^ ABS module

G1:

G1 (Continued)-G2:

G3-G4: