Antitheft and Alarm Systems

Diagnostic Trouble Code (DTC) Charts:

CIRCUIT DESCRIPTION
When the ignition is switched On, the antenna that is integrated in the theft deterrent module (immobilizer) is energized. During this period, the Engine Control Module (ECM) sends a signal to terminal 2 of the theft deterrent module requesting the frequency code (imo signal).

The transponder key contains a security code (transponder code) that transmits via the antenna to the theft deterrent module. The theft deterrent module compares the received code with the stored transponder code. If the transponder code is recognized, the theft deterrent module blocks the speed signal input to the ECM allowing the transfer of the imo signal to terminal 44 of the ECM. The ECM compares the received imo signal with the programmed imo signal. If the signal is recognized and matches the programmed signal the engine is allowed to start.

Within 1.5 seconds during the transfer and evaluation phase of the transponder code and the imo signal, the engine can be started. However, if the imo signal does not match, the engine will stall immediately.

CONDITIONS FOR SETTING THE DTC
^ No transponder signal (key transmitter signal) is present, the transponder key is defective.
^ The key being used is not a transponder key.
^ The transponder key is not programmed in the theft deterrent module.
The above conditions must be fulfilled for at least 0.51 seconds.

ACTIONS TAKEN WHEN THE DTC SETS
^ The engine starts, then stalls.
^ The theft deterrent module stores a DTC 14 in memory.

CONDITIONS FOR CLEARING THE DTC
^ The conditions for the fault are no longer present.
^ A history DTC will clear after 20 consecutive ignition cycles if the condition for the fault is no longer present.
^ Use a scan tool in order to clear this DTC.

DIAGNOSTIC AIDS
^ Test the ground circuit at terminal 4 (BLK). Perform a voltage drop test, refer to Measuring Voltage Drop. Diagnostic Aids

Typical voltage drop readings are 100 mV or less. When measuring the resistance, the resistance should measure at close to 0 (zero) ohms. Diagnostic Aids
^ Test the power circuits at terminal 5 (BRN) and terminal 9 (RED).

TEST DESCRIPTION
The following numbers refer to the step numbers on the diagnostic table:
2. This step checks which transponder key is being used.
4. This step checks the programmed status of the key being used.
8. The module may be at fault if no trouble is found in the power or ground circuits, or if no trouble is found with the connection at the theft deterrent module.