Service Brake Booster Message Displayed
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, 2004 Chevrolet Cab & Chassis Silverado, and 2003 GMC Sierra. However, it is still accessible from the selected car via links, so may be relevant.
Service Brake Booster Message Displayed
| Step | Action | Values | 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 | Go to Symptoms - Hydraulic Brakes |
| 2 | Start the engine. Is the reduced brake power message displayed within 5 seconds? |
- | Go to Reduced Brake Power Message Displayed | Go to Step 3 |
| 3 | Is the service brake booster message displayed within 5 seconds? | - | Go to Step 6 | Go to Step 4 |
| 4 | Operate the vehicle at a speed greater than 48 km/h. Is the service brake booster message displayed? |
- | Go to Step 5 | Go to Diagnostic Aids |
| 5 | Test the charging system for proper operation. Refer to Charging System Test (CS/AD/SI Generators)
in Engine Electrical. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 21 |
| 6 |
|
- | Go to Step 7 | Go to Step 12 |
| 7 | Test each SBA ground circuit for an open. Refer to Circuit Testing
and to Wiring Repairs
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 8 |
| 8 | Connect a test lamp between the engine ON signal circuit and a good ground. Does the test lamp illuminate? |
- | Go to Step 10 | Go to Step 9 |
| 9 | Repair the open in the engine ON signal circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 22 | - |
| 10 | Use a DMM to measure the voltage between the vehicle speed signal circuit and a good ground. Does the voltage measure greater than the specified value? |
10 V | Go to Step 13 | Go to Step 11 |
| 11 | Repair the open in the vehicle speed signal circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 22 | - |
| 12 | Repair the open in the ignition 1 circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 22 | - |
| 13 | Use a DMM to measure the voltage between the supplemental brake assist circuit and a good ground. Does the voltage measure greater than the specified value? |
11 V | Go to Step 16 | Go to Step 14 |
| 14 |
|
- | Go to Step 22 | Go to Step 15 |
| 15 | Inspect for poor connections at the IPC harness connector. Refer to Testing for Intermittent Conditions and Poor Connections
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 19 |
| 16 | Connect a test lamp between the SBA signal circuit and a good ground. Does the test lamp illuminate? |
- | Go to Step 17 | Go to Step 20 |
| 17 |
|
- | Go to Step 18 | Go to Step 19 |
| 18 | Repair the short to voltage in the SBA signal circuit. Refer to Wiring Repairs
in Wiring Systems. Did you complete the repair? |
- | Go to Step 22 | - |
| 19 | Replace the IPC. Refer to Instrument Panel Cluster (IPC) Replacement
in Instrument Panel, Gages, and Console. Did you complete the replacement? |
- | Go to Step 22 | - |
| 20 | Inspect for poor connections at the SBA harness connector. Refer to Testing for Intermittent Conditions and Poor Connections
in Wiring Systems. Did you find and correct the condition? |
- | Go to Step 22 | Go to Step 21 |
| 21 | Replace the SBA pump motor assembly. Refer to Brake Assist Pump Motor Replacement . Did you complete the replacement? |
- | Go to Step 22 | - |
| 22 |
|
- | Go to Step 2 | System OK |