For 1990-2009 cars
Theft Deterrent System Components
Theft Deterrent System Schematics

### Circuit Description

The body control module (BCM) will read an analog voltage form the Passlock sensor. Based on an internal reference, the BCM will determine if the measured voltage is in one of the following conditions:

• | Open

• | Shorted to ground

• | A valid code

• | A tamper code

There are 10 possible valid code combination. The BCM will only recognize the last learned valid code.

### Conditions for Running the DTC

The ignition switch is cycled to CRANK and released to ON.

### Conditions for Setting the DTC

• | The ignition switch is ON.

• | The BCM signal input is greater than 4.9 volts for 1 second after turning the ignition switch to the CRANK position.

### Action Taken When the DTC Sets

• | If the DTC sets during cranking, the car will not start and the theft indicator is on continuously.

• | If the DTC sets while the engine is running, the car will start on future attempts.

• | The SERVICE VEHICLE SOON indicator illuminates.

### Conditions for Clearing the DTC

• | Current DTCs will clear after one ignition cycle if the malfunction is no longer present.

• | All of the BCM history codes will be cleared after 100 ignition cycles (from OFF to ON) with no current codes active during the 100 ignition cycles.

### Diagnostic Aids

• | If the malfunction occurred during engine crank, this DTC may not set.

• | Inspect for a poor connection at the Passlock® sensor and BCM.

• | If the DTC is a history DTC, the problem may be intermittent. Perform the test shown while wiggling the wiring and connectors. This will cause the malfunction to appear.

### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. Tests for proper operation of the circuit in the high voltage range.

2. Tests for a short to ground in the Passlock sensor signal circuit.

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

1. Install a scan tool.
2. Momentarily rotate the ignition switch to CRANK (do not start the vehicle).
3. Release the ignition switch to ON.
4. With a scan tool, observe the PASSLOCK DATA VOLTAGE parameter in the SECURITY DATA data list.

Does the scan tool indicate that the PASSLOCK DATA VOLTAGE is within the specified range?

0.4-4.9v

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the Passlock ™ sensor connector.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool, observe the PASSLOCK DATA VOLTAGE in the SECURITY DATA data list.

Does the scan tool indicate that the PASSLOCK DATA VOLTAGE is less than the specified value?

4.9v

Go to Step 7

Go to Step 4

4 |

1. Test the Passlock sensor signal circuit for a short to voltage or an open.
2. Test the Passlock battery voltage circuit for an open.
3. Test the Passlock ground circuit for an open.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 9

Go to Step 5

5 | Inspect for poor connections at the BCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 6
6 | Replace the BCM. Refer to Body Control Module Replacement in Body Control System. Important: Perform the setup procedure for the body control module. Refer to Body Control Module (BCM) Programming/RPO Configuration . Did you complete the replacement? | -- | Go to Step 9 | --
7 | Inspect for poor connections at the Passlock ™ sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 9 | Go to Step 8
8 | Replace the Passlock™ sensor. Important: Perform the relearn procedure for the Passlock™ sensor. Refer to PASSLOCK Reprogramming Auto Learn . Did you complete the replacement? | -- | Go to Step 9 | --
9 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 2

System OK