Brake Pedal Switch

Brake Pedal Switch

Fuse 9 of the passenger compartment fuse box (C0586) provides an auxiliary ignition feed to the brake pedal switch (C0075) on a PY wire. When the brake pedal is pressed, the switch (C0075) provides the ECM (C0331) a voltage of between 6 V and battery voltage on an NS wire. When the pedal is released, the switch provides the ECM a voltage of between approximately 0 and 2 V. Once the ECM registers the brake pedal has been pressed, it will suspend cruise control operation.

The brake pedal switch (C0075) also provides a test signal to the ECM (C0331) on a UR wire. The switch (C0075) is earthed on an NB wire.

CAN Bus

When cruise control is activated, the ECM (C0331) informs the automatic transmission ECU via the CAN Bus on YN (low) and YB (high) wires. The automatic transmission ECU will change its shift patterns accordingly. For more information on automatic transmission operation, refer to the Automatic Transmission – ZF 5HP24 or Automatic Transmission – GM5L40–E section of the System Description and Operation Workshop Manual, and the Electronic Automatic Transmission – ZF or Electronic Automatic Transmission – GM5 section of this manual.  ELECTRONIC AUTOMATIC TRANSMISSION (EAT) – ZF.  ELECTRONIC AUTOMATIC TRANSMISSION (EAT) – GM5.

Rotary Coupler

The rotary coupler (C0082) receives an ignition feed from fuse 9 of the passenger compartment fuse box (C0587) on a PY wire, and is earthed on an NB wire. The rotary coupler (C2287) receives voltage pulse messages from the LH steering wheel module (C2283) as follows:

A cruise control on/off signal on a W wire. A set/accelerate signal on a U wire. A decelerate signal on an R wire. A resume signal on a B wire.

The messages from the LH steering wheel module are relayed from the rotary coupler (C0082) to the ECM (C0331) on a YB wire. The ECM interprets this message and controls the throttle pedal accordingly.