Component Tests and General Diagnostics

The antilock control module generates and displays flash codes from the ANTILOCK indicator light to help identify the cause of an antilock system fault. The microprocessor memory will store and display only one fault code at a time. Any stored code can be displayed by grounding the service diagnostic connector.

Two different RWAL control modules were installed on the 1992 model vehicles. Some early production models used the type I module, while the later production models were equipped with a type II module.

The type I and II modules can be identified by the way fault codes 9 and 11 are processed. If the vehicle has a type I module, codes 9 and 11 are not erased when the ignition switch is turned to OFF position. On vehicles with the type II module, codes 9 and 11 are erased when the switch is turned to OFF.

TYPE I CONTROL MODULE
The self test feature of the control module is activated whenever the ignition switch is turned to ACCESSORY or RUN position.
If a system fault is detected, the control module illuminates the ANTILOCK light and stores the fault code in memory. Fault codes are retained in memory even after turning the ignition switch to OFF position.

TYPE II CONTROL MODULE
The self test feature of the control module is activated whenever the ignition switch is turned to ACCESSORY or RUN position.

If a system fault is detected, the control module will illuminate the ANTILOCK indicator lamp and store the fault code except for fault codes 9 and 11. When a code other than 9 or 11 is generated, the control module will retain the code in memory after the ignition switch is turned to the OFF position.

When fault code 9 is generated, the code only remains in microprocessor memory while the ignition switch is in RUN position. Fault code 9 is erased when the ignition switch is turned to OFF position. However, if the problem still exists when the switch is turned back to RUN position, code 9 will reappear in memory after 20 seconds and the antilock light will illuminate once again.

When fault code 11 is generated, the antilock light will illuminate when vehicle speed exceeds approximately 37.5 m.p.h. Code 11 remains in memory only while the ignition switch is in the RUN position.

When the cause of a fault code 11 is corrected, the antilock light goes off. If the problem cause still exists when the ignition switch is turned to RUN position, code 11 will reappear when vehicle speed exceeds approximately 37.5 m.p.h..

FAULT CODE IDENTIFICATION
To determine what a fault code is, first turn the ignition key to RUN position. Then momentarily ground the service diagnostic connector and count the number of times the antilock indicator light flashes.

RWAL System Fault Codes:

The initial flash will be a long flash followed by a number of shorter flashes. The long flash indicates the beginning of the fault number sequence and the short flashes are a continuation of that sequence. The long flash must be counted along with the short flashes in order to obtain an accurate fault code count.

CLEARING A FAULT CODE
To clear a fault code, disconnect the control module connector or battery for a minimum of five seconds. During system retest, wait 30 seconds to be sure the fault code does not reappear.