Normal Operation

WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.

The ABS module monitors the master cylinder piston position to determine whether the brake is being applied or not and with how much force. The sensor has 2 sets of 3 circuits:

Low resolution circuits

LCB26 (BU/BN)
VCB27 (GY/YE)
RCB26 (GN/WH)

The ABS module sends a 5-volt reference voltage to the sensor along circuit LCB26 (BU/BN). The voltage returns along circuit RCB26 (GN/WH) and the piston position is determined using the voltage that is sent back to the ABS module along circuit VCB27 (GY/YE).

High resolution circuits

LCA27 (BN/WH)
VCA30 (YE/VT)
RCA27 (WH)

The ABS module sends a 5-volt reference voltage to the sensor along circuit LCA27 (BN/WH). The voltage returns along circuit RCA27 (WH) and the piston position is determined using the voltage that is sent back to the ABS module along circuit VCA30 (YE/VT).

DTC C1526 Brake Pedal Travel Sensor Fault - If the ABS module detects an open, a short to voltage or a short to ground on the both the low resolution and the high resolution circuits of the brake pedal travel sensor, DTC C1526 will be set. This DTC will also be set if the information the ABS module receives from the travel sensor does not match the other brake pedal sensors.

This pinpoint test is intended to diagnose the following:

Wiring, terminals or connectors
Brake pedal travel sensor (part of the master cylinder)
ABS module (part of the hydraulic control unit [HCU])