Code P033, Extended Travel Brake Switch Input Circuit Problem: Action

PCM disables cruise control and substitutes status of TCC contacts of TCC brake switch input for the extended travel input. PCM turns on SERVICE VEHICLE SOON light message.

1. PCM input PI86 should cycle from high to low when brake pedal is depressed and then released. If PI86 remains low, check for open or short to ground in system. If PI86 remains high, check for short to voltage in system.
2. If 10 volts or greater is measured, check circuit No. 847 or TCC brake switch for open circuit. If less than 10 volts is measured, check circuits No. 341 and 847 for a short to ground.

Fig 1: Code P033 Schematic, Extended Travel Brake Switch Input Circuit Problem

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P033Diagnostic Flow Chart, Extended Travel Brake Switch Input Circuit Problem

Courtesy of GENERAL MOTORS CORP.