Pinpoint Test J: DTC C1288 and C1440
Anti-Lock Control
Pinpoint Tests
Pinpoint Test J: DTC C1288 and C1440
Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number
Normal Operation
The ABS module monitors the pressure of the hydraulic brake system through the use of a brake pressure transducer. The brake pressure transducer is internal to the Hydraulic Control Unit (HCU). The brake pressure transducer can not be serviced separately. If a new brake pressure transducer is needed, a new HCU must be installed.
- DTC C1288 Pressure Transducer Main / Primary Input Circuit Failure - If there is an improper connection between the ABS module and HCU, if the brake pressure transducer is faulted or if the ABS module is faulted internally, this DTC will set.
- DTC C1440 Pressure Transducer Main / Primary Signal Faulted - If there is an improper connection between the ABS module and the HCU, if there is air in the hydraulic brake system, if the brake pressure transducer is faulted or if the ABS module is faulted internally, this DTC will set.
This pinpoint test is intended to diagnose the following:
- HCU
- ABS module
PINPOINT TEST J: DTC C1288 AND C1440
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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J1 MONITOR THE PCM BRAKE ON/OFF (BOO) PID
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Press and release the brake pedal while monitoring the BOO PID.
- Does the PID switch to ON with the brake pedal pressed and then to OFF with the brake pedal released?
Yes
GO to J2.
No
RETRIEVE any PCM DTCs. REFER to Computers and Control Systems Information for non-communication DTCs and REFER to Information Bus for any communication DTCs.
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J2 REVIEW THE ABS MODULE DTCs
- Enter the following diagnostic mode on the scan tool: Clear All CMDTCs .
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module .
- Retrieve and record any ABS module DTCs.
- Is DTC C1288 or C1440 present?
Yes
GO to J4.
No
GO to J3.
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J3 CHECK FOR RETURNING DTCs
- Enter the following diagnostic mode on the scan tool: Clear All CMDTCs .
- Drive the vehicle in a straight line at a speed greater than 40 km/h (25 mph) for at least 60 seconds.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module .
- Retrieve and record any ABS module DTCs.
- Is DTC C1288 or C1440 present?
Yes
For DTC C1288, GO to J5.
For DTC C1440, GO to J4.
No
The concern is not present at this time. TEST the vehicle for normal operation.
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J4 CARRY OUT THE ABS SERVICE BLEED
- Carry out the Brake System Service Bleed, Refer to Brakes and Traction Control. Clear the DTCs. Repeat the self-test.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Clear All CMDTCs .
- Drive the vehicle in a straight line at a speed greater than 40 km/h (25 mph) for at least 60 seconds.
- Enter the following diagnostic mode on the scan tool: Self Test - ABS Module .
- Is DTC C1288 or C1440 present?
Yes
GO to J6.
No
The system is operating correctly at this time. The concern may have been caused by air trapped in the hydraulic brake system.
TEST the system for normal operation.
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J5 CHECK THE ABS TO HCU CONNECTION
- Ignition OFF.
- Disconnect: ABS Module C155.
- Remove the ABS module. Refer to Anti-Lock Brake System (ABS) Module Service and Repair.
- Inspect the ABS module-to-HCU mating surfaces for damage or contamination.
- Are the ABS-to-HCU mating surfaces OK?
Yes
GO to J7.
No
INSTALL a new ABS module and a new HCU. REFER to Hydraulic Control Unit (HCU) Service and Repair and Anti-Lock Brake System (ABS) Module Service and Repair.
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J6 CHECK THE ABS MAIN BRAKE PRESSURE (MPRETDR) PID
- If not already done, separate the ABS module from the HCU. Refer to Anti-Lock Brake System (ABS) Module Service and Repair.
- With the ABS module separated from the HCU, connect ABS module C155.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger - ABS Module .
- Monitor the MPRETDR PID.
- Is the PID value at 0?
Yes
INSTALL a new HCU. REFER Hydraulic Control Unit (HCU) Service and Repair. CLEAR the DTCs. TEST the system for normal operation.
No
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. CLEAR the DTCs. TEST the system for normal operation.
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J7 CHECK FOR CORRECT ABS MODULE OPERATION
- Check ABS module C155 for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Connect: ABS Module C155.
- Make sure the connector seats correctly, 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. TEST the system for normal operation.
No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test.
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