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Pinpoint Test E: DTC C1446




Anti-Lock Control

Pinpoint Tests

Pinpoint Test E: DTC C1446

Refer to Wiring Diagram Set 42, Vehicle Dynamic Systems for schematic and connector information. Diagrams By Number

Refer to Wiring Diagram Set 60, Instrument Cluster for schematic and connector information. Diagrams By Number

Refer to Wiring Diagram Set 90, Turn Signal/Stop/Hazard Lamps for schematic and connector information. Diagrams By Number

Normal Operation

The Brake Pedal Position (BPP) switch (also known as the stoplamp switch) is hardwired to the PCM. When the brake pedal is pressed, a voltage signal is sent to the PCM. The PCM then sends a message to the ABS module over the High Speed Controller Area Network (HS-CAN) bus indicating that the brake pedal has been pressed.

The brake fluid level switch is hardwired to the Smart Junction Box (SJB) and sends brake fluid level information directly to the SJB. The SJB then sends the brake fluid level information to the Instrument Cluster (IC) along the Medium Speed Controller Area Network (MS-CAN) bus. The IC sends the brake fluid level information out to other modules (including the ABS module) along the HS-CAN bus.

- DTC C1446 (Brake Switch Circuit Failure) - The ABS module monitors the BPP message sent from the PCM and compares that message to the wheel speed sensor inputs. If there are no wheel speed sensor DTCs present and the BPP message does not match wheel speed sensor input, the ABS module will set DTC C1446. Also, if the brake fluid level message from the IC reports the fluid level as "low", "unknown" or "invalid" then the ABS module will also set DTC C1446.

This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Brake fluid level
- BPP switch
- ABS module



PINPOINT TEST E: DTC C1446

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E1 CHECK 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.
- Monitor the BOO_ABS PID while pressing and releasing the brake pedal several times.
- Does the PID display match the pedal position every time?

Yes
GO to E3.

No
GO to E2.

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E2 CHECK THE PCM BOO PID


- Enter the following diagnostic mode on the scan tool: DataLogger - PCM.
- Monitor the BOO PID while pressing and releasing the brake pedal several times.
- Does the PID display match the pedal position every time?

Yes
REFER to Information Bus to diagnose the HS-CAN bus.

No
REFER to Lighting and Horns to diagnose the stoplamp switch.

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E3 CHECK THE BRAKE FLUID LEVEL


- Verify that the brake fluid level in the master cylinder reservoir is at the correct level.
- Is the brake fluid level OK?

Yes
GO to E4.

No
ADJUST the fluid as necessary. CLEAR the DTC. REPEAT the self-test.

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E4 CHECK FOR BRAKE FLUID LEVEL DTCs IN THE SJB


- Enter the following diagnostic mode on the scan tool: Self Test - SJB.
- Retrieve and record all SJB DTCs.
- Are any brake fluid level DTCs present in the SJB?

Yes
REPAIR all SJB brake fluid level DTCs before addressing C1446. REFER to the Diagnostic Trouble Code (DTC) Chart in Body Control Systems. Diagnostic Trouble Code (DTC) Chart

No
GO to E5.

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E5 CHECK FOR IC COMMUNICATION (U-CODE) DTCs


- Enter the following diagnostic mode on the scan tool: Self Test - IC.
- Retrieve and record all IC DTCs.
- Are any U-code DTCs present?

Yes
REPAIR all IC U-codes before addressing DTC C1446. REFER to Diagnosis and Testing in Instrument Panel, Gauges and Warning Indicators. Testing and Inspection

CLEAR the DTC. REPEAT the self-test.

No
GO to E6.

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E6 CHECK THE RED BRAKE WARNING INDICATOR OPERATION


- Monitor the red brake warning indicator in the IC.
- Ignition OFF.
- Ignition ON.
- Verify that the red brake warning indicator illuminates for 3 seconds and then extinguishes.
- Does the red brake warning indicator illuminate for 3 seconds and then extinguish?

Yes
GO to E7.

No
REFER to Instrument Panel, Gauges and Warning Indicators to diagnose the red brake warning indicator.

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E7 CHECK THE ABS MODULE CONNECTOR


- Ignition OFF.
- Disconnect: ABS Module C135.
- Check the connector for:
- corrosion.
- pushed-out pins.
- spread terminals.
- Is the connector OK?

Yes
GO to E8.

No
REPAIR the connector as necessary. CLEAR the DTC. REPEAT the self-test.

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E8 CHECK FOR CORRECT ABS MODULE OPERATION


- Connect: ABS Module C135.
- Make sure the connector is seated correctly, then clear the DTC and repeat the ABS module self-test.
- Does the DTC return?

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.

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