| Last Modified: 11-29-2007 | 1.6 D | |
| Service Category: Vehicle Interior | Section: Theft Deterrent/Keyless Entry | |
| Model Year: 2008 | Model: Sequoia | Doc ID: RM000001TCO009X |
| Title: THEFT DETERRENT / KEYLESS ENTRY: ENGINE IMMOBILISER SYSTEM: SYSTEM DESCRIPTION (2008 Sequoia) | ||
SYSTEM DESCRIPTION
1. ENGINE IMMOBILISER SYSTEM DESCRIPTION
The engine immobiliser system is designed to prevent the vehicle from being stolen. This system uses the 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.
2. FUNCTION OF MAIN COMPONENT
|
Component |
Outline |
|---|---|
|
Transponder key amplifier |
When key is inserted into ignition key cylinder, antenna coil receives key code. Then amplifier amplifies ID code and outputs it to transponder key ECU. |
|
Transponder key ECU |
Transponder key ECU verifies transponder key ID code amplified by immobiliser coil/amplifier When key ID code is correct, ECU transmits signal to allow engine to start. |
|
ECM |
Receives ID verification results from transponder key ECU assembly. ECM also verifies ECUs. Then judgment of whether to immobilise the engine is made. |
|
Unlock warning switch |
Detects whether key is in ignition key cylinder and outputs results to transponder key ECU. |
|
Security indicator light |
Depending on operation of transponder key ECU, security indicator light comes on or starts blinking. |
|
Front door courtesy light switch LH |
Located on front door LH. Detects door status (open or closed) and outputs data to main body ECU. Turns on when door is open and turns off when door is closed. |
3. SYSTEM FUNCTION
(a) When the transponder key ECU detects that the unlock warning switch is ON, the transponder key ECU provides current to the antenna coil and produces a faint electric wave. A transponder chip in the key grip receives the electric wave. Upon receiving the electric wave, the transponder chip outputs a key ID code signal. The transponder key coil receives this signal, the signal is amplified by the transponder key amplifier, and the signal is transmitted to the transponder key ECU.
(b) The transponder key ECU matches the key ID code with the vehicle ID code, which was previously registered in the transponder key ECU, and communicates the results to the ECM. After the identification results show that the key ID code matches the vehicle ID code and the transponder key ECU has confirmed their match: 1) the engine immobiliser system is canceled and the engine starting controls (fuel injection control and ignition control) enter standby mode; and 2) the transponder key ECU transmits a security indicator light signal that communicates "indicator OFF" to the accessory meter (security indicator light), and the security indicator light turns off.
(c) The security indicator light pattern is as shown below (when changing from the immobiliser set status to the unset status).
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