For 1990-2009 cars

### 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 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.

• | 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.

• | The use of a scan tool.

### Diagnostic Aids

Refer to Inducing Intermittent Fault Conditions in Wiring Systems.

### Test Description

The following numbers refer to the step numbers on the diagnostic table:

1. This step checks which transponder key is being used.

2. This step checks the programmed status of the key being used.

3. 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.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Theft Deterrent Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - Theft Deterrent
2 |

1. Install a scan tool.
2. Select IMMOBILIZER.
3. Turn the ignition ON, with the engine OFF.
4. Select TRANSPONDER KEY from the data list.

Does the scan tool display a transponder key (TRANSP KEY 1-5)?

--

Go to Step 4

Go to Step 3

3 | Does the scan tool display NOT PROGR KEY? | -- | Go to Step 5 | Go to Step 6
4 | Select TRANSPONDER KEY STATUS. Does the scan tool display KEYS PROGRAMMED? | -- | Go to Diagnostic Aids | Go to Step 7
5 |

1. Check the key for a missing transponder. If the transponder is missing, repair as needed.
2. If OK, the key is defective, replace as needed.

Is the repair or replacement complete?

--

Go to Step 7

--

6 | Does the scan tool display NO KEY PROGR? ( Key being used is not programmed in the Theft Deterrent Module.) | -- | Go to Step 7 | --
7 | Program the transponder key. Refer to Programming Transponder Key. Was the programming successful? | -- | Go to Step 8 | Go to Step 9
8 |

1. Use the scan tool in order to clear the DTCs.
2. Turn OFF the ignition.
3. Remove the scan tool.
4. Start the vehicle.

Does the vehicle start?

--

System OK

Go to Step 10

9 | Inspect for poor connections at the theft deterrent module connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 8 | Go to Step 11
10 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Select the Immobilizer DTC display function.

Does the DTC reset?

--

Go to Step 9

Go to Step 11

11 | Replace the theft deterrent module. Did you complete the replacement? | -- | Go to Step 12 | --
12 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | --