Interview the customer to confirm the trouble

The theft deterrent system will operate when somebody attempts to forcibly enter the vehicle, unlock any door or luggage compartment door or open the engine hood or the luggage compartment door without using the key. This system causes the interior light to light up, hazard warning lights, headlights and taillights to blink and the vehicle horn and security horn to sound in order to deter break-in and theft.

Lexus IS250 IS220d GSE20 ALE20 THEFT DETERRENT

Lexus IS250 IS220d GSE20 ALE20 THEFT DETERRENT

While using the battery during inspection, do not bring the positive and negative tester probes too close to each other as a short circuit may occur.

This circuit provides power for main body ECU RH operation.

Even when the theft deterrent system is in the disarmed state, the security indicator blinks due to a signal output from the immobiliser system. The security indicator blinks continuously due to a continuous signal received from the immobiliser system while in the armed state.

The main body ECU RH causes the security indicator to light up or blink only during the arming preparation state and alarm sounding state.

Measure the voltage according to the value(s) in the table below.

When the engine switch is turned on (IG), positive (+) battery voltage is applied to the main body ECU RH (cowl side J/B RH). When battery positive (+) voltage is applied to terminal IG of the main body ECU (cowl side J/B RH) while the theft deterrent system is operating, the warning stops.

When the theft deterrent system is operating, the relay in the main body ECU RH turns on and off, causing the security horn to sound.