Pinpoint Test I: DTCs C1288 and C1440
Anti-Lock Control - Non-Hybrid
Pinpoint Test I: DTCs C1288 and C1440
Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. [1][2]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 cannot be serviced separately. If a new brake pressure transducer is needed, a new HCU (Hydraulic Control Unit) must be installed.
- DTC C1288 (Pressure Transducer Main/Primary Input Circuit Failure)- If there is an improper connection between the ABS module and HCU (Hydraulic Control Unit) , if the brake pressure transducer is faulted or if the ABS module is faulted internally, this DTC sets.
- DTC C1440 (Pressure Transducer Main/Primary Signal Faulted)- If there is an improper connection between the ABS module and the HCU (Hydraulic Control Unit) , 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 sets.
This pinpoint test is intended to diagnose the following:
- HCU (Hydraulic Control Unit)
- ABS module
PINPOINT TEST I : DTCs C1288 AND C1440
NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.
I1 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 I2.
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.
I2 REVIEW THE ABS MODULE DTCs
- Connect the scan tool.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Clear All ABS Module DTCs.
- Ignition OFF.
- Ignition ON.
- 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 I4.
No
GO to I3.
I3 CHECK FOR RETURNING DTCs
- Enter the following diagnostic mode on the scan tool: Clear All ABS Module DTCs.
- 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 I5.
For DTC C1440, GO to I4.
No
The concern is not present at this time. For all other DTCs, REFER to the ABS Module DTC Chart. ABS Module DTC Chart
I4 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 ABS Module DTCs.
- 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 I6.
No
The system is operating correctly at this time. The concern may have been caused by air trapped in the hydraulic brake system.
CLEAR the DTCs. REPEAT the self-test.
I5 CHECK THE ABS TO HCU (Hydraulic Control Unit) CONNECTION
- Ignition OFF.
- Disconnect: ABS Module C135.
- Remove the ABS module. Refer to Anti-Lock Brake System (ABS) Module .
- Inspect the ABS module-to-HCU (Hydraulic Control Unit) mating surfaces for damage or contamination.
- Inspect the 4-pin pressure sensor connector in the ABS module and on the HCU (Hydraulic Control Unit) side for damage, corrosion or contamination.
Are the ABS-to-HCU (Hydraulic Control Unit) mating surfaces undamaged and free of contamination or corrosion?
Yes
GO to I6.
No
INSTALL a new HCU (Hydraulic Control Unit). REFER to Hydraulic Control Unit (HCU) . If there is visible damage to the ABS module, INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module .
I6 CHECK THE ABS MAIN BRAKE PRESSURE (MPRETDR) PID
- If not already done, separate the ABS module from the HCU (Hydraulic Control Unit). Refer to Anti-Lock Brake System (ABS) Module .
- With the ABS module separated from the HCU (Hydraulic Control Unit) , connect ABS module C135.
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: DataLogger- ABS Module.
- Monitor the MPRETDR PID.
Is the PID value between 21.13K and 22.59K?
Yes
INSTALL a new HCU (Hydraulic Control Unit). REFER Hydraulic Control Unit (HCU) . CLEAR the DTCs. TEST the system for normal operation.
No
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module . CLEAR the DTCs. TEST the system for normal operation.