Anti-Lock Brake System Diagnostic System Check
- Connect scan tool to Data Link Connector (DLC). DLC is located under instrument panel, near steering column. Turn ignition switch to RUN position. Using scan tool, attempt to establish communication with Electronic Brake Control Module (EBCM). If communication is not established with EBCM, go to next step. If communication is established with EBCM, go to step 3.
- Using scan tool, attempt to establish communication with Sensing and Diagnostic Module (SDM). If communication is established with SDM, go to next step. If communication is not established with SDM, perform TEST C: SCAN TOOL DOES NOT COMMUNICATE WITH UART DATA LINE under SYSTEM TESTS.
- Following scan tool manufacturer's instructions, select DISPLAY DTCs function for EBCM. If no DTCs are set as current, go to next step. If any DTCs are set as current, perform appropriate test in accordance with DTCs retrieved. See appropriate ANTI-LOCK article in BRAKES.
- Turn ignition switch to LOCK position. Remove scan tool. Turn ignition switch to RUN position. Observe ABS warning light. If ABS warning light turns on, then turn off after several seconds, go to next step. If ABS warning light does not turn on, then turn off after several seconds, go to step 6.
- Turn ignition switch to LOCK position. Turn ignition switch to RUN position. Observe LOW TRACTION warning light. If LOW TRACTION warning light turns on, then turn off after several seconds, go to step 8. If LOW TRACTION warning light does not turn on, then turn off after several seconds, go to step 7.
- If ABS warning light stays on, repair ABS warning light. See appropriate ANALOG INSTRUMENT PANELS article. If ABS warning light does not come on, repair ABS warning light. See appropriate ANALOG INSTRUMENT PANELS article.
- If LOW TRACTION warning light stays on, repair LOW TRACTION warning light. See appropriate ANALOG INSTRUMENT PANELS article. If LOW TRACTION warning light does not come on, repair LOW TRACTION warning light. See appropriate ANALOG INSTRUMENT PANELS article.
- Turn ignition switch to LOCK position. Connect scan tool to DLC. Turn ignition switch to RUN position. Following scan tool manufacturer's instructions, select DISPLAY DTCs function. If no DTC are displayed as history, system is okay at this time. If any DTCs are displayed as history, go to next step.
- Read diagnostic aids and conditions for setting DTC. Carefully road test vehicle for several minutes, at a speed above 15 MPH while monitoring a scan tool for ABS DTCs. If a history DTC set as a current DTC while vehicle was being driven, perform appropriate test in accordance with DTCs retrieved. See appropriate ANTI-LOCK article in BRAKES. If no history DTC set as a current DTC while vehicle was being driven, system is okay at this time.