Catera V6-3.0L VIN R (1997)
Engine Control Module: Description and Operation
Theft Deterrent Circuit
There are no circuits dedicated to communication between the ECM and the Theft Deterrent Module. The ECM and the Theft Deterrent Module
exchange data using two existing circuits. The Malfunction Indicator Lamp (MIL) Control circuit connects to the ECM and the Theft Deterrent Module.
When the ignition switch is turned on, and the ECM illuminates the MIL (bulb check), the voltage change on the MIL Control circuit is used as a wake
up signal to the Theft Deterrent Module. If a problem with this circuit prevents the Theft Deterrent Module from receiving the wake up signal, a
Diagnostic Trouble Code (DTC) will set. The Vehicle Speed Signal circuit is also connected to both the ECM and the Theft Deterrent Module. The
Theft Deterrent System Frequency Code relays between the two controllers via this circuit. DTCs that apply to the problems that are detected with the
exchange of data between the ECM and the Theft Deterrent Module are as follows:
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DTC P1501 - Theft Deterrent System
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DTC P1502 - Theft Deterrent System - No Password Received
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DTC P1503 - Theft Deterrent System - Password Incorrect