ABS - With Commercial Chassis

(Part 1 Of 2):

(Part 2 Of 2):

CIRCUIT DESCRIPTION
The pump motor is an integral part of the BPMV, while the pump motor relay is integral to the EBTCM. The pump motor relay is not engaged during normal system operation. When an ABS/TCS event occurs, the EBTCM activates the pump motor relay and battery power is provided to the pump motor.

CONDITION FOR SETTING THE DTC
DTC C1217 will set anytime the pump motor relay is commanded ON and the pump relay voltage is less than 8 volts, and ignition voltage is greater than 10.5 volts.

ACTION TAKEN WHEN THE DTC SETS
A malfunction DTC is stored, ABS/TCS is disabled and the ABS and TRACTION CONTROL indicator lamps are turned ON.

CONDITIONS FOR CLEARING THE DTC
Condition for DTC is no longer present and scan tool clear DTC function is used. Fifty start cycles have passed with no DTCs detected.

DIAGNOSTIC AIDS
It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction. A problem in the Power Distribution system may result in no battery voltage to CKT 1042. Fuse 1 (ABS MOTOR) is open. There is an internal malfunction in the EBTCM or the BPMV. The Relays are integral to the EBTCM and are not serviceable.

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
4. Checks for a short to ground in CKT 1042.
5. Checks for an internal short in the BPMV.
8. Checks for an open in CKT 1042.