Test B: DTCs C1095 and C1096 - ABS Hydraulic Pump Motor Circuit Failure/Open

Pinpoint Test B: DTCs C1095 and C1096 ABS Hydraulic Pump Motor Circuit Failure/Open

Normal Operation
Fused battery voltage for the hydraulic control unit (HCU) pump motor is supplied to the ABS module by battery junction box (BJB) fuse 6 (40A) along circuit SBB06 (BN/RD). Ground for the HCU pump, coil and ABS module is provided along circuit GD163 (BK/GY). The ABS module supplies the voltage and ground for the pump motor. The 2 components are hardwired together, there are no connectors or wiring harnesses between the 2 components.

The ABS module performs 2 different tests on the pump motor to determine the condition of the motor. The first test is done when the ignition key is turned to the ON position and is used to test for a pump motor that may be locking up. The ABS module commands the HCU pump motor on for 100 ms (±6 ms) and then commands the pump motor off, once the pump motor is commanded off, it will generate a small amount of voltage. Six milliseconds after commanding the pump off, the ABS module will read the voltage that is being generated by the pump motor. If the voltage indicates the motor is spinning at less than 500 rpm, the motor may be locking up.

The second test is used to check for an open circuit and a short to voltage. Two seconds after the most recent (successful) pump motor off command, the ABS module will read the voltage that is being generated by the pump motor. If the voltage generated remains greater than 0.75 volt for more than 50 ms (±6 ms) after the off command, then a short to voltage may exist. If there is no voltage generated by the pump motor, then an open circuit condition may exist.

DTC C1095 ABS Hydraulic Pump Motor Circuit Failure - If a short to voltage or ground is detected, if a locked up pump motor is detected 4 times or if there is an internal failure of the ABS module (short to voltage or ground), DTC C1095 will be set.

DTC C1096 ABS Hydraulic Pump Motor Circuit Open - If a short to voltage, a short to ground or an open is detected or if there is an internal failure of the ABS module (short to voltage or ground), DTC C1096 will be set.

This pinpoint test is intended to diagnose the following:
^ Wiring, terminals or connectors
^ Hydraulic pump motor
^ ABS module

B1:

B2-B4:

B4 (Continued)-B5: