DTC P033: Extended Travel Brake Switch Input Circuit Problem: Action

1. PCM disables cruise control.
2. PCM will substitute the status of the TCC contacts of the torque management brake switch input for the extended travel input.
3. PCM turns on the "SERVICE VEHICLE SOON" message.
4. Turn on the "CHECK INFO CENTER" telltale.

NOTE: Numbers in list refer to circled numbers in diagnostic flow chart, see Fig 1. For circuit identification see Fig 2.

1. PCM input PI86 should cycle from "HI" to "LO" to "HI" when brake pedal is depressed and then released. If PI86 remains "LO", there is an open or short to ground in the system. If PI86 remains "HI", there is a short to voltage in the system.
2. If 10 volts or greater is measured, check CKT 1725 or torque management brake switch for an open. If less than 10 volts is measured check CKT 350 and CKT 1725 for a short to ground.

Fig 1: DTC P033: Extended Travel Brake Switch Input Circuit Problem Flow Chart

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC P033: Extended Travel Brake Switch Input Circuit Problem Flow Chart Circuit

Courtesy of GENERAL MOTORS CORP.