Pinpoint Test D: DTC B1484

Anti-Lock Control

Pinpoint Tests

Pinpoint Test D: DTC B1484

Normal Operation

Fused battery voltage is sent to the Brake Pedal Position (BPP) switch from Central Junction Box (CJB) fuse 14 (20A) along circuit 1119 (RD). When the brake pedal is pressed, the BPP switch closes and the voltage is then supplied to CJB fuse 28 (7.5A) along circuit 511 (LG) and then to the ABS module along circuit 1651 (WH/RD). The ABS module compares the BPP switch signal to BPP messages sent over the High Speed Controller Area Network (HS-CAN) bus to verify that the BPP switch signal is accurate.

The BPP switch is also known as the stoplamp switch.

- DTC B1484 (Brake Pedal Input Open Circuit) - If the BPP switch circuit 1651 (WH/RD) is open, DTC B1484 will set.

This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- BPP switch
- ABS module

PINPOINT TEST D: DTC B1484

NOTICE: The Flex Probe Kit must be used for all test connections. Use of standard multi-meter probes may damage wiring terminals.

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D1 CHECK THE BRAKE LAMP OPERATION


- Press the brake pedal.
- Do the brake lamps illuminate?

Yes
GO to D2.

No
REFER to Exterior Lighting Testing and Inspection to diagnose the stoplamps.

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D2 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 Module.
- Monitor the BOO_ABS PID while pressing and releasing the brake pedal.
- Does the BOO_ABS PID display ON with the brake pedal pressed and OFF with the brake pedal released?

Yes
CLEAR the DTCs. REPEAT the self-test. If DTC B1484 is retrieved, INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. REPEAT the self-test.

No
GO to D3.

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D3 CHECK THE VOLTAGE TO THE ABS MODULE


NOTE: Make sure the brake pedal is released for this step.

NOTE: To access the ABS module connector, remove the Air Cleaner (ACL) assembly.

- Disconnect: ABS Module C135.
- Press and hold the brake pedal.
- Measure the voltage between ABS module C135-30, circuit 1651 (WH/RD), harness side and the ABS module C135-38, circuit 57 (BK), harness side.




- Is the voltage greater than 10 volts?

Yes
INSTALL a new ABS module. REFER to Anti-Lock Brake System (ABS) Module Service and Repair. TEST the system for normal operation.

No
VERIFY CJB fuse 28 (7.5A) is OK. If OK, REPAIR circuit 1651 (WH/RD). If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the self-test. Diagrams By Number

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