The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses a transponder key ecu that stores the key codes of authorized ignition keys. If an attempt is made to start the engine using an unauthorized key, the ecu sends a signal to the ecm to prohibit fuel delivery and ignition, effectively disabling the engine.

The transponder key coil receives this signal, the transponder key amplifier amplifies it, and then the signal is transmitted to the ecu. The ecu matches the key's id code with the vehicle's id code, which was previously registered in the ecu and then communicates the results to the ecm using sfi communication.
Engine immobiliser system
How to proceed with troubleshootingSteering column assembly
Components
Removal
Caution:
Some of these service operations affect the srs airbag
system. Read the precautionary notices concerning the
srs airbag system before servicing the steering column
(see page rs-1).
Place front wheels facing straight ahead
Disconnect cab ...
How to proceed with troubleshooting (2005/11-2006/01)
Hint:
Use these procedures to troubleshoot the air conditioning
system.
*: Use the intelligent tester.
Vehicle brought to workshop
Customer problem analysis and symptom check
Inspect battery voltage
Standard voltage:
11 to 14 v
If the voltage is below 11 v, rechar ...
Removal
Drain engine coolant (see page co-6)
Disconnect cable from negative battery
terminal
Caution:
Wait at least 90 seconds after disconnecting the
cable from the negative (-) battery terminal to
prevent airbag and seat belt pretensioner activation.
Remove no. 1 Engine cover
Remove ...