Circuit Description
When an ignition key is inserted in the ignition switch, the terminals located in the ignition lock cylinder contact the resistor pellet in the key. The body control module (BCM) measures the resistance of the key pellet and then compares the resistance to the one stored in memory. If the BCM has been replaced, the new BCM needs to learn the ignition key code value. The BCM learns the first key code value when the ignition is first turned to ON.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC B3031 Security System Controller In Learn Mode
Conditions for Setting the DTC
The BCM does not have a valid key pellet resistance in memory.
Conditions for Clearing the DTC
The BCM learns the next valid key pellet resistance and stores the resistance in memory.
Diagnostic Aids
| • | If any other theft deterrent DTCs are also set current, diagnose that DTC first. |
| • | This DTC sets on replacement BCMs until the first valid key pellet is detected by the BCM. |
Step | Action | Yes | No |
|---|---|---|---|
Schematic Reference: Theft Deterrent System Schematics | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle in Vehicle DTC Information |
2 |
Does the scan tool display DTC B3031 as a current DTC? | Go to Step 3 | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems |
3 |
Does the vehicle start and run? | Go to Step 5 | Go to Step 4 |
4 | Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup and programming. Did you complete the replacement? | Go to Step 5 | -- |
5 |
Does the DTC reset? | Go to Step 2 | System OK |
