Schematic Reference: Hydraulic Brake Schematics

Connector End View Reference: Hydraulic Brake Connector End Views Antilock Brake System Connector End Views and Displays and Gages Connector End Views

1

Did you review the Brake Warning System Description and Operation, and the Brake Assist System Description and Operation, and perform the necessary inspections?

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Go to Step 2

Go to Symptoms - Hydraulic Brakes

Perform the Brake Assist System Diagnosis .

Did you find and correct the condition?

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Go to Step 8

Go to Step 3

1. Disconnect the supplemental brake assist (SBA) harness connector.
2. Turn the ignition ON.
3. Use a DMM to measure the voltage between the supplement a brake assist signal circuit and a good ground.

Does the voltage measure greater than the specified value?

11 V

Go to Step 5

Go to Step 4

1. Remove the instrument panel cluster (IPC) from the instrument panel. Refer to Instrument Cluster Replacement .
2. Test the SBA signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 8

Go to Step 6

With the SBA harness connector still disconnected, start the engine.

Is the reduced brake power message displayed?

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Go to Step 6

Go to Step 7

Replace the IPC. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

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Go to Step 8

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Replace the SBA pump motor assembly. Refer to Power Brake Booster Auxiliary Pump Replacement .

Did you complete the replacement?

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Go to Step 8

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Start the engine.

Is the reduced brake power message displayed?

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Go to Step 2

System OK