DTC P106: Stop Lamp Switch Input Circuit Problem: Action

1. Traction control disabled.
2. PCM will set the Stop BTSI/Cruise brake switch status to not applied.
3. "TRACTION DISABLED" and "REDUCED ENGINE POWER" message is displayed on the CCDIC.
4. Turns on "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. Checking if PCM input test PI89 will cycle when brake pedal is depressed and released. If PI89 remains "HI", check for a short to voltage in the system. If PI89 remains "LO", check for an open or short to ground in the system.
2. Checking for voltage supplied to the brake switch.
3. Checking CKT 140 for a short to ground.
4. Checking CKT 20 for a short to ground.
5. Checking CKT 20 for an open or for a bad PCM.

Fig 1: DTC P106: Stop Lamp Switch Input Circuit Problem Flow Chart

Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC P106: Stop Lamp Switch Input Circuit Problem Flow Chart Circuit

Courtesy of GENERAL MOTORS CORP.