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 79 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 the 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) present, transponder key defective. |
| • | Key used is not a transponder key. |
| • | Transponder key not programmed in the Theft Deterrent Module. |
The above conditions must be fulfilled for at least 0.51 seconds.
Action Taken When the DTC Sets
The engine starts then stalls.
Conditions for Clearing the DTC
| • | The conditions for the fault are no longer present. |
| • | The ignition switch was cycled 20 times. |
| • | The use of a scan tool. |
Diagnostic Aids
| • | Using the DMM, check the ground circuit at terminal 4. Typical voltage drop readings are 100mV or less. When measuring the resistance it should measure at close to 0 (zero) ohms. |
| • | Use Terminal Repair Kit J 38125-A or J 35616-A to gauge all terminal contacts. Check for damaged connectors and poor wire to terminal connections. Refer to 8A-4-5 for procedure. |
| • | If the DTC is an intermittent DTC, try performing the tests shown while "wiggling" wiring and connectors, this can often cause the malfunction to appear. |
Test Description
The following numbers refer to the step numbers on the diagnostic table:
-
This check determines which transponder key is being used.
-
This checks the programmed status of the key being used.
-
The module may be fault if no trouble is found in the power circuits, if no trouble is found in the ground circuits, or if no trouble is found at the connection at the Theft Deterrent Module. However, this is an extremely unlikely failure.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Immobilizer System Check Performed? | -- | ||
Does the scan tool display match the key number in the value? | TRANSP KEY 1 | |||
3 | Does the scan tool display NOT PROGR. KEY? | -- | ||
Select TRANSPONDER KEY STATUS. Does the scan tool display KEYS PROGRAMMED? | -- | |||
5 |
Is the repair or replacement complete? | -- | -- | |
6 | Does the scan tool display NO KEY PROGR? ( Key being used is not programmed in the Theft Deterrent Module.) | -- | -- | |
7 | Reprogram the transponder key. Refer to Programming Transponder Key Important: Once the keys have been erased and reprogrammed, cycle the ignition OFF and ignition ON again. The parameter value is only updated if communication is interrupted and then re-estaablisted if other erwise, the scan tool may indicate No TRANSPONDER KEY, even though the transponder keys were programmed. Was the programming successful? | -- | ||
Is the replacement and the reprogramming complete? | -- | -- |
