Test Driving Vehicle

Due to the fact that Fault Codes are erased upon key-off, most Anti-lock Brake System (ABS) complaints will require a test drive as a part of the diagnostic procedure. The purpose of the test drive is to duplicate the condition and set the Fault Code. For this reason, it is important not to turn the ignition off after the test drive until the Fault Codes have been displayed (if any are present).

Before test driving a brake complaint vehicle, especially if the BRAKE warning lamp is on, test the brakes at low speed to be sure that the car will stop normally. The following procedure should be used to test drive an ABS complaint:
1. Turn the ignition switch to the ON position without starting the car and wait until the BRAKE warning and ANTI-LOCK warning lamps turn off. This allows the pump to charge the accumulator to operating pressure. If the warning lamp(s) do not turn off, proceed to step 3.
2. Turn the ignition OFF for 15 seconds.
3. START car, and wait for displays to return to normal operating mode before proceeding.
4. With Shift lever in PARK, slowly depress brake pedal and release. Be sure to use a full pedal stroke. If the BRAKE warning lamp was previously off but comes on when the brake pedal is depressed, proceed to step 6.
5. Drive the vehicle a short distance. During this test drive, be sure that the vehicle achieves at least 20 miles per hour. Brake to at least one complete stop and accelerate slowly to at least 20 mph.
6. If at any time during the test drive the BRAKE warning lamp or ANTI-LOCK warning lamp appear, enter ABS Diagnostic Service Mode and record Fault Codes which have been set, if any.
7. After recording the Fault Code, return to FUNCTIONAL CHECK and proceed with the appropriate diagnostic procedure. If no Fault Codes are present, return to FUNCTIONAL CHECK.