46 Auto Brakes Copyright by Goodheart-Willcox Co., Inc. General Motors Figure 3-40. Typical troubleshooting chart found in most service manuals. Symptom Table: Amber ABS Warning Indicator on Constantly, NO DTCs Stored Step Action Value(s) Yes No 1 Was the Diagnostic System Check performed? — Go to Step 2 Go to Diagnostic System Check 2 1. Turn the ignition switch to the OFF position. 2. Install a scan tool. 3. Turn the ignition switch to the RUN position. 4. Using the scan tool, select MISC TESTS. 5. Using the scan tool, select LAMP TEST. 6. Using the scan tool, turn the amber ABS warning indicator off. Did the amber ABS warning indicator turn off? — Go to Step 3 Go to Step 4 3 1. Using the scan tool, select MISC TESTS. 2. Using the scan tool, select LAMP TEST. 3. Using the scan tool, flash the amber ABS warning indicator. Did the amber ABS warning indicator flash? — Go to Step 7 Go to Step 4 4 Inspect all connectors and terminals for poor terminal contact and evidence of corrosion. Is there evidence of poor terminal contact or corrosion? — Go to Step 5 Go to Step 6 5 Replace all terminals that exhibit signs of poor terminal contact or corrosion. Is the repair complete? — Go to Diagnostic System Check — 6 Repair the instrument panel cluster. Refer to SECTION 8A-8I. Is the repair complete? — Go to Diagnostic System Check — 7 Malfunction not present at this time. Refer to Diagnostic Aids for more information. — — — instead indicate the fl ow or process within the system. Some schematics show the exact fl ow of a form of energy while others show the general process of a particular system. Sche- matics are oft en included as part of a service manual, or may be supplied separately. Tracing the fl ow through a schematic makes diagnosis easier by showing the exact path of electricity or other form of energy. Each line represents a single wire in the vehicle’s wiring harness. Th e schematic lines are labeled with num- bers or colors to correspond with a specifi c color, or color and color stripe combination on the actual wires. Th e path can be traced by carefully following the lines from compo- nent to component. Always carefully note the color designa- tions of the wires and any stripes or bands to ensure you are following the correct wire. Troubleshooting Charts Troubleshooting charts are summaries, or checklist ver- sions, of the troubleshooting information about a particular vehicle or system. Although the information is found in a longer form elsewhere in a service manual, the trouble- shooting chart allows the technician to quickly reference the problem, the possible cause, and the solution. Figure 3-40 shows a typical troubleshooting fl owchart. Some trouble- shooting charts are arranged with the problem on the left - hand side of the page, the possible cause in the middle, and the corrective action on the right-hand side. Technical Service Bulletins Frequently, manufacturers issue technical service bulletins (TSB), for newer vehicles to their dealership personnel. Th ese bulletins contain repair information that is used to describe a new service procedure, correct an unusual or frequently occurring problem, or update information in a service manual. Many of the phone hotline and comput- erized assistance services receive these bulletins. Th ey are a very good source of information to repair an unusual or