Pinpoint Test B: DTCs C1095 And C1096 - ABS Hydraulic Pump Motor Circuit Failure/Open
Anti-Lock Control
Pinpoint Tests
Pinpoint Test B: DTCs C1095 and C1096 - ABS Hydraulic Pump Motor Circuit Failure/Open
Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
Fused battery voltage for ABS pump motor operation is supplied to the ABS module from the Bussed Electrical Center (BEC) fuse 8 (40A) along circuit 534 (YE/LG). Ground for the pump motor is provided along circuit 1205 (BK).
When the ignition key is turned to the ON position, the ABS module commands the Hydraulic Control Unit (HCU) pump on for 100 ms (±6 ms) and is then commanded off. After 6 ms, the ABS module will read the voltage that is being generated by the HCU pump. If the voltage indicates the motor is spinning at less than 500 rpm, there may be a locked motor. If this condition is detected 4 times, DTC C1095 is set. The pump motor is checked for an open circuit 2 seconds after the most recent successful pump motor off command. If the pump motor feedback remains greater than 0.75 volt for more than 50 ms (±6 ms) after these conditions have been met, DTC C1096 is set.
- 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 or if there is an internal failure of the ABS module, 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, if a locked up pump motor is detected or if there is an internal failure of the ABS module, DTC C1095 will be set.
This pinpoint test is intended to diagnose the following:
- Fuse
- Wiring, terminals or connectors
- Hydraulic pump motor
- ABS module
PINPOINT TEST B: DTCs C1095 AND C1096 - ABS HYDRAULIC PUMP MOTOR CIRCUIT FAILURE/OPEN
NOTICE: Use the Flex Probe Kit for all test connections to prevent damage to the wiring terminals. Do not use standard multi-meter probes.
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B1 CHECK THE ABS PUMP MOTOR
- Ignition ON.
- Is the ABS pump motor running all the time?
Yes
INSTALL a new ABS module and HCU. REFER to Anti-Lock Brake System (ABS) Module Service and Repair and Hydraulic Control Unit (HCU) Removal and Replacement. CLEAR the DTCs. REPEAT the ABS self-test.
No
GO to B2.
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B2 CHECK THE PUMP MOTOR OUTPUT COMMAND (ABS_MTR)
- Connect the scan tool.
- Enter the following diagnostic mode on the scan tool: ABS DataLogger.
- Toggle the ABS_MTR output command ON.
- Does the ABS pump motor run for approximately 2 seconds?
Yes
TOGGLE the output command OFF.
CLEAR the DTCs. CHECK the yellow ABS warning indicator while driving the vehicle (brakes must not be applied) above 32 km/h (20 mph). If the yellow ABS warning indicator illuminates, RETRIEVE the DTCs.
If DTC C1096 is retrieved, GO to B5.
If DTC C1095 is retrieved, INSTALL a new HCU. REFER to Hydraulic Control Unit (HCU) Removal and Replacement.
For all other ABS module DTCs, GO to the ABS Module DTC Chart. ABS Module DTC Chart
CLEAR the DTCs. REPEAT the self-test.
No
TOGGLE the output command OFF and GO to B3.
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B3 CHECK THE VOLTAGE TO THE ABS MODULE
- Ignition OFF.
- Disconnect: ABS Module C135.
- Measure the voltage between ABS module C135-31, circuit 534 (YE/LG), harness side and ground.
- Is the voltage greater than 10 volts?
Yes
GO to B4.
No
VERIFY BEC fuse 8 (40A) is OK. If OK, REPAIR circuit 534 (YE/LG). CLEAR the DTCs. REPEAT the self-test.
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B4 CHECK CIRCUIT 1205 (BK) FOR AN OPEN
- Measure the resistance between ground and:
- ABS module C135-45, circuit 1205 (BK), harness side.
- ABS module C135-16, circuit 1205 (BK), harness side.
- Are the resistances less than 5 ohms?
Yes
INSTALL a new HCU. REFER to Hydraulic Control Unit (HCU) Removal and Replacement. CLEAR the DTCs. REPEAT the self-test.
No
REPAIR the affected circuit(s). CLEAR the DTCs. REPEAT the self-test.
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B5 CHECK FOR CORRECT ABS MODULE OPERATION
- Ignition OFF.
- Disconnect: ABS Module C135.
- Check the connector for:
- corrosion.
- spread terminals.
- pushed-out pins.
- Connect: ABS Module C135.
- Make sure the connector seats properly, then operate the system and verify the concern is still present.
- Is the concern still present?
Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. CLEAR the DTCs. REPEAT the self-test.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. CARRY OUT the self-test with the brake pedal not applied.
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