Pinpoint Test G: DTCs C116A, C1440

Anti-Lock Control

Pinpoint Test G: DTCs C116A, C1440


Normal Operation

The pressure transducer is integral to the Hydraulic Control Unit (HCU). The pressure transducer sends a signal to the ABS module that varies in relation to the amount of pressure applied to the brake pedal. The more pressure that is applied, the greater the signal sent to the ABS module. If a new pressure transducer is needed, then a new HCU (Hydraulic Control Unit) must be installed.

When the brake pedal is pressed, the stoplamp switch closes and a voltage is sent to the PCM. The PCM then sends a message over the High Speed Controller Area Network (HS-CAN) to the ABS module indicating that the brake pedal has been pressed. DTCs set in the ignition cycle can only be cleared by cycling the ignition off and on once the fault has been corrected.

- DTC C116A (ABS Pressure Transducer / Brake Switch Mismatch)- this DTC sets in every ignition cycle if, during normal operation, the stoplamp switch message does not match the HCU (Hydraulic Control Unit) transducer, both signals have to agree about whether the brakes are being applied or not.

- DTC C1440 (Pressure Transducer Main/Primary Signal Faulted)- this DTC sets in every ignition cycle if the signal that the pressure transducer sends to the ABS module does not agree with the stoplamp switch position.

This pinpoint test is intended to diagnose the following:

- HCU (Hydraulic Control Unit)

- ABS module

PINPOINT TEST G : DTCs C116A, C1440

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

G1 MONITOR THE ABS MODULE BRAKE ON/OFF (BOO_ABS) PID

- Connect the scan tool.

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: DataLogger- ABS Module.

- Press and release the brake pedal while monitoring the BOO_ABS PID.

Does the PID display ON with the brake pedal applied and OFF with the brake pedal released?

Yes
GO to G3.
No
GO to G2.

G2 MONITOR THE PCM BRAKE ON/OFF (BOO1) PID

- Enter the following diagnostic mode on the scan tool: DataLogger- PCM.

- Press and release the brake pedal while monitoring the BOO1 PID.

Does the PID display ON with the brake pedal applied and OFF with the brake pedal released?

Yes
REFER to Information Bus to continue diagnosis of the HS-CAN (High Speed Controller Area Network).
No
REFER to Lighting and Horns to continue diagnosis of the stoplamp switch fault.

G3 MONITOR THE INITIAL (BRAKE PEDAL NOT APPLIED) BRAKE PRESSURE USING THE ABS MODULE BRAKE PRESSURE (BRAKPRES) PID

- Enter the following diagnostic mode on the scan tool: DataLogger- ABS Module.

- With the brake pedalnot applied, record the pressure displayed by the BRAKPRES PID.

Is the initial brake pressure less than 275 kPa (40 psi) with the brake pedal not applied?

Yes
GO to G4.
No
INSTALL a new HCU (Hydraulic Control Unit). REFER to Hydraulic Control Unit (HCU) .

G4 MONITOR THE BRAKPRES PID WHILE APPLYING THE BRAKE PEDAL

- Enter the following diagnostic mode on the scan tool: DataLogger- ABS Module.

- Firmly press and release the brake pedal while monitoring the BRAKPRES PID.

Does the PID increase with firm pressure on the brake pedal and then decrease with the brake pedal released?

Yes
The system is operating correctly at this time. TEST the system for normal operation.
No
INSTALL a new HCU (Hydraulic Control Unit). REFER to Hydraulic Control Unit (HCU) .