Engine Controls - Revised Code 53, VATS
90pont14Bulletin Number: 89-6-82
Reference Number: 016522
Publish Date: 6/90
Subject: SERVICE MANUAL UPDATE - SECTION 6E2 DRIVEABILITY AND EMISSIONS REVISED CODE 53 (VATS) FACING PG, CHART
Models
Affected: 1989 FIREBIRD MODELS WITH 5.0L (VIN E)
The Code 53 Vehicle Anti-Theft System (VATS) service diagnostics for the 1989 5.0L L03 (VIN E) Firebird models have been revised.
Use the information in this bulletin in place of the Code 53 chart and facing page schematic found on pages 6E2-A-52 and 6E2-A-53 in the "Driveability And Emissions" Section "6E2" for the above mentioned vehicle.
CODE 53
VEHICLE ANTI-THEFT SYSTEM (VATS) CIRCUIT 5.0L (VIN E) "F" CARLINE (TBI)
Circuit Description:
The VATS system is designed to disable vehicle operation if the incorrect key or starting procedure is used. The VATS decoder module sends a signal to the ECM if the correct key is being used. If the proper signal does not reach the ECM on CKT 229, the ECM will not pulse the injectors "ON" and thus not allow the vehicle to be started. Code 53 will set, if the proper signal is not being received on CKT 229 ECM when the ignition is turned "ON." Code 53 does not store in the ECM memory but is only present when the conditions stated above are met.
Test Description: Numbers below refer to circled numbers on the diagnostic chart.
1. If the engine cranks, and a Code 53 is stored, it indicates that the portion of the module which generates the signal to the ECM is not operating or CKT 229 is open or shorted to ground. If the decoder module is found to be OK, as determined from Section "8A", the ECM may be at fault, but this is not a likely condition.
2. If Code 53 is stored, and the engine will not crank, it indicates that there is a non-ECM related VATS problem or an incorrect key or starting procedure is being used.