Vehicle on-Board Diagnostics

Normal Indicator Lamp Sequence:

Indicator Lamp Sequence Chart:

The second step in diagnosis of any Antilock Brake System condition is determination of the warning light behavior. As described in System Operation above, the Antilock Brake System uses two warning lamps, including a red "BRAKE" warning lamp and an amber "ANTI-LOCK" lamp. By observing when these lamps light, specific components and sub-systems of the brake system may be isolated as likely causes of a system malfunction.

The normal indicator lamp sequence is shown and indicator lamp sequences are shown graphically as described below.

Vehicle Status

Each light sequence illustration is divided into seven areas which represent vehicle status, with the behavior of the "BRAKE" and "ANTI-LOCK" lights represented in the horizontal rows below the vehicle status headers.

Light Status

"BRAKE" and "ANTI-LOCK" light status is indicated by the shaded areas in the horizontal rows below each vehicle status header. Right-hand diagonal shading indicates illumination of the "ANTI-LOCK" light, while a left-hand diagonal shading indicates a lit "BRAKE" light. A vehicle status block which is not entirely shaded means that the light is on only for part of the test period.