See Figure 1
The individual ABS components cannot be tested individually per se; however, the entire ABS can be tested by retrieving and reading the Diagnostic Trouble Codes (DTC's) stored in the control module. The ABS-CM constantly monitors the entire system for faults or problems. When the ABS is operating normally, the ABS warning indicator light (on the instrument panel) will illuminate for approximately three seconds when the ignition key is turned ON or when the engine is started. If the warning indicator light stays illuminated for more than three seconds, or illuminates while driving, then a malfunction has been detected by the ABS-CM. If a problem is found by the ABS-CM, it will store a DTC corresponding to the component which exhibited the problem. Up to three DTC's can be stored by the ABS-CM at one time. The DTC does not only refer to the component in question, but also to the component's wiring harness circuit. If a code is detected, check the component's wiring for a short-to-ground or an open circuit before replacing the component; doing so may save you a lot of money, if the problem lies within the wiring.
It is important to perform the quick test prior to retrieving the ABS diagnostic trouble codes; it may save you some time and effort.Quick Test
- Turn the ignition switch to the ON position.
Note the activity of the ABS warning indicator light on the instrument cluster:
- The ABS warning indicator light should illuminate for approximately three seconds when the ignition key is turned ON or when the engine is started. If the warning light functions normally, no DTC's are stored in the ABS-CM.
- If the warning indicator light stays illuminated for more than three seconds, or illuminates while driving, then a malfunction has been detected by the ABS-CM; read the DTC's for the cause of the malfunction.
READING THE CODES
See Figures 2 and 3
To properly read the ABS DTC's can only be read with a Super Star Tester II 007-0041B, or an equivalent scan tool.
- Turn the ignition switch to the OFF position.
- Find the ABS diagnostic connector, located on the engine compartment power distribution box (left-hand inner fender).
- Attach the scan tool connector to the ABS diagnostic connector.
During the reading of the DTC's, the diagnostics will be disrupted and the ABS-CM will return to normal operation if the vehicle travels over 15 mph (24 km/h), the ABS-CM senses an ungrounded diagnostic connector for more than 15 seconds, or if the ignition switch is turned OFF.
- Turn the scan tool on, then move the latch button to the TEST position. Ensure that the scan tool is in slow mode.
- Turn the ignition switch to the RUN position (with the engine off). The DTC's will begin to flash on the scan tool screen. The ABS-CM will store a maximum of three DTC's. If any DTC's have been detected, each code will be flashed out once, and only once, after entering the diagnostic mode. If no DTC's have been stored, a DTC 12 will be presented. After all DTC's have been flashed out, the ABS warning indicator light will remain on until the ignition switch is turned OFF .
Refer to the accompanying illustration for what the DTC's will look like when being flashed out by the scan tool.CODE IDENTIFICATION
See Figures 4 through 18
The diagnostic trouble codes are as follows:
DIAGNOSTIC PINPOINT TESTS
Depending on the DTC's read from your system, refer to the accompanying diagnostic charts. The corresponding tests for each DTC are as follows: