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Trouble Analysis Diagnose:
The Lexus RX200T occur this problem:sound and display screen still work after turnning power off,and other electric device:air-condition,seat heating can turn off correctly.
Normally,sound and display screen will shut down ,the device should be in a dormant state after power off.But now,the power switch has been off,the device still working,it indicating that the power supply for them is not cut off.When troubleshooting,you need to check sound and display power supply first.Below shows the sound system diagram:the radio assembly has three power terminals:+B1(battery power supply),ACC1(ACC power supply),IG(IG ON power supply).As long as the ACC and +131 power supply, the radio can work normally.Analyse the radio supply circuit and trouble symptom,it recommand that there were faults in the ACC1 power supply circuit. The display screen circuit is the same as radio system,you just check radio circuit first.The Lexus RX200T is a new car which has never wire damaged and modificaiton on it.So the possibility of wire fault is small,we need to check other relevant factors firstly.
When technician removed the connector of air cleaner form power outlet,the trouble disappeared,radio and display screen can turn off correctly.And plug the air cleaner connector back,the trouble appear again.After testing again and again,the test result are same:this problem is due to air cleaner connector.
Maintenance Summary:
1. Why does the air cleaner caused the trobule and affect the radio work?
The air cleaner equiped with built-in power supply,it work correctly power by built-in power when external power be cut off.When the power swith of ACC or IG in on position,the air cleanr power by vehicle.When you turn off the vehicle power,the vehicle power outlet power by air cleaner built-in power.then power outlet supply power for ECU-ACC circuit.At this time,part of vehicle electric devices have working conditions,so occur the symptom:the radio and display screen still working after cut off power.
2.There are a lot of on-board attachments are equipped with charge and discharge functions, such as driving recorder, car air purifier, charge Po, etc., most of these devices through the connection cigarette lighter or external power port to obtain power, when the vehicle suffer from power related failure, first of all we should to disconnect these additional equipment, to avoid detours.
3.Many vehicle additional equipments have design flaw and lack considerations for impacts of vehicle.It will result in a variety of vehicle failure,such as:parasitic current increases, the total loss of battery, GPRS signal can not receive, etc., in the exclusion Electrical failure, first of all to disconnect these accessories equipment, to avoid detours.
From Auto Repair Technician Home, post Lexus RX200T Power Off: Sound and Displasy Screen Still Work
