Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Brake Warning System Schematics | |||
1 | Did you review the Brake Warning System Description and Operation and the Brake Assist System Description and Operation and perform the necessary inspections? | Go to Step 2 | |
2 | Start the vehicle. Is the REDUCED BRAKE POWER message displayed for 1 minute before the SERVICE BRAKE BOOSTER message is displayed? | Go to Step 3 | Go to Step 4 |
3 | Perform the Brake Assist System Diagnosis Did you find and correct the condition? | Go to Step 12 | Go to Step 11 |
4 |
Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 5 |
5 | Test both ground circuits for opens. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 6 |
6 | Test the engine on signal circuit for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 7 |
7 | Test the vehicle speed signal circuit for an open. Did you find and correct the condittion? | Go to Step 12 | Go to Step 8 |
8 | Test the supplemental brake assist signal circuit for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 12 | Go to Step 9 |
9 |
Did the DMM flash battery voltage? | Go to Step 11 | Go to Step 10 |
10 | Replace the Supplemental Brake Assist pump motor assembly Refer to Power Brake Booster Auxiliary Pump Replacement . Did you complete the replacement? | Go to Step 12 | -- |
11 | Replace the instrument panel cluster. Refer to Instrument Cluster Replacement in Instrument Panel, Gages and Console. Did you complete the replacement? | Go to Step 12 | -- |
12 | Start the engine. Does the Service Brake Booster message stay on? | Go to Step 2 | System OK |
