Initial Inspection and Diagnostic Overview

Fig. 1 LED flashing pattern of a trouble code 22.:

The Anti-Lock warning lamp will illuminate if a malfunction in the Anti-lock brake system is detected by the Electronic Brake Control Module (EBCM). The anti-lock lamp is intended only to inform the driver that a condition has been detected which results in anti-lock lamp illumination, and there may be a possible problem with the hydraulic brake system. The lamp will remain on during the entire ignition cycle.
The Anti-Lock brake system is equipped with self diagnostic capability which may be used to assist in isolation of ABS failures. The Anti-Lock warning lamp and the Light Emitting Diode (LED) located on the EBCM, under the passenger seat will continue to flash trouble codes even after the failure has been repaired, unless the ignition switch is turned off. Ensure ignition switch is turned Off after the repair, then operate vehicle for one minute at 19 mph to confirm the diagnostic results.

Reading ABS Trouble Codes

When the LED flashes the trouble code, be careful to count only the number of times the light turns on and goes out. Code 22 is shown as an example in Fig. 1. The length of flashes shown is in seconds.

Trouble code diagnosis

Some diagnostic procedures require that the ignition switch remain on for extended periods of time while tests are performed. Low battery voltage may result, causing erroneous voltage readings. If vehicle system voltage becomes low, it is advisable to connect a battery charger and apply a slow charge while testing. Refer to DIAGNOSTIC CHARTS for diagnosis procedures.