Security System Indicates Tamper
Circuit Description
The passlock sensor data is supplied to the body control module (BCM) by circuit
1836.
The passlock sensor data supplied to the BCM is in the form of V-codes or voltage
codes. When the proper ignition key is turned in the ignition switch, the correct
V-code is supplied to the BCM. The BCM responds by sending a serial data password
to the engine controller allowing the engine to run.
The security resistor is bypassed under a tamper condition (possible external
magnet applied to sensor). In this mode, a specific V-code is supplied to the BCM.
The vehicle will not start in this mode.
Conditions for Setting the DTC
| • | Ignition is in RUN, CRANK |
| • | The passlock data equals stored tamper V-code for 1 second |
| • | Turns on service wrench telltale and security telltale |
Diagnostic Aids
| • | Check for poor connection at the BCM. Inspect harness connectors for backed
out terminals, improper terminal mating, broken connector locks, improperly formed
or damaged terminals and poor terminal-to-wire connection (terminal crimped over
wire insulation and not conductors). |
| • | Inspect the wiring harness for damage. Check for broken or
chafed insulation. |
| • | Check for poor connection at the passlock sensor. |
| • | If fault is suspected to be intermittent, wiggling harness wiring may
help in locating fault. |
