P033

Diagnostic Trouble Code Chart P033:

Electronic Brake And Traction Control Module Circuit:

CIRCUIT DESCRIPTION
This diagnostic test functions on the assumption that a sudden decrease in non-drive (rear) wheel speed must be caused by a brake application. Non-drive wheel speed and stop lamp switch status are supplied to the Powertrain Control Module (PCM) through serial data from the Electronic Brake and Traction Control Module (EBTCM). If there is a 2.5 mph or greater decrease of non-drive wheel speed in 0.2 second and a transition of the Torque Converter Clutch (TCC) contacts at the torque management brake switch or stop lamp switch without a transition of the extended travel contacts of the torque management brake switch the counter is incremented. When the counter reaches 5, Code P033 is set. The counter will be reset to zero if a transition of the extended travel contacts of the torque management brake switch is noticed before the counter reaches 5.

TEST CONDITIONS
1. Codes P090, P106 and P137 not set.
2. Traction control and antilock brake systems are operating normally.
3. Non-drive wheel speed of 36 mph or greater.
OR
Non-drive wheel speed has been 36 mph or greater and has not fallen below 1.2 mph since.

FAILURE CONDITIONS
1. A 2.5 mph or greater decrease in non-drive wheel speed in 0.2 second.
2. Transition in the TCC contacts of the torque management brake switch or Stop/Brake-Transmission Shift Interlock (BTSI)/Cruise brake switch.
3. No transition noticed in the extended travel contact of the torque management brake switch.
4. If conditions 1 through 3 are true, increment counter.
5. When counter reaches 5, set Code P033.

ACTION TAKEN
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" "Check Info Center" telltale.

NOTES ON FAULT TREE
1. PCM input P186 should cycle from "HI" to "LO" to "HI" when brake pedal is depressed and then released. If P186 remains "LO," there is an open or short to ground in the system. If P186 remains "HI," there is a short to voltage in the system.
2. If 10 volts or greater is measured, check CKT 847 or TCC brake switch for an open. If less than 10 volts is measured check CKT 341 and CKT 847 for a short to ground.