I own a 2005 GX 470 recently I got in to drive the car and the navigation screen would work for climate control and audio functions but the map would not display. A bunch of warning lights were also on ABS, VSC etc. Upon investigation I found the ECU-B fuse was blown. I replaced the fuse and everything appeared to be fine. About 3 days later and the same thing happened again. I again replaced the fuse and it lasted a couple of days and blew again. I have not been able to isolate it to any one thing that seems to trip it. Has anyone seen this issue or have any idea how to best determine the cause of the issue?

 

The ECU-B2 fuse is directly related to the Anti Theft System. Check in the Engine Bay the following fuse.
1.Door Lock/anti Theft /Mirror Systems. It will be mentioned as DR/LCK25A. and the Head Relay. If you have the Nav System equipped, then check aslo the Mayday Fuse - 7.5 Amp.

 

I appreciate your feedback. In my case however it is the ECU-B fuse not the ECU-B2 fuse that is the issue. Any idae waht systems are connected to that control unit?

 

Both are same, they are inter-related. The following areas are direct impact on this ECU-B & ECU-B2.
ECU-B - Anti - Theft,Headlights,Interior Lights,Power Windows,Mirrors,Navigation,Electronic Power Steering,Power Seats,Instrument Cluster,Electronic Suspension,Air Conditioning, Wiper Washer Uni,ABS.
The Latter one has more so on the Anti-Theft System because of the Theft Deterrent System, and the Engine Immobilizer.

 

Same problem here. Happened 10 months ago, replaced the fuse. Just happened again yesterday, tech says the driver's side mirror is shorting. Makes sense, fuse blew just after I put it in reverse and mirrors tilted.

 

You can put the mirror selection switch in the middle position to disable the reverse-tilt function -- until the mirror motor module comes in.

Chip H.

 

I agree with the above poster, I had the same issue, and after going thru 7 fuses. It was driver side mirror, when I tried to adjust up and down the fuse would blow, or when I put in reverse.

When this fuse goes out, the mirror would not work, clock reset, anti-theft off, driver seat memory and VSC off VSC trac lights would come on.

The best thing to do is change the mirror actuator, or leave the mirror switch in the middle position.

 

After doing some trouble shooting I found the ECU-b fuse under the hood was blown. I replaced it and all was fixed until I put the SUV in reverse. Come to find out there is a known issue with the driver door mirror actuator. When the SUV is placed in reverse, the mirror tilts down. The actuator shorts out very often (so much Lexus issued a TSB on it). When the mirror tilts down it shorts out and blows the fuse.

For a temp fix, place your mirror switch in the center and don't adjust the driver mirror. If the switch is in center, the mirror will not move when you go into reverse.

For a permanent fix, call Lexus and see if you are under warranty. If you are not ask them to cover half of the charge to repair. We were out of warranty and they paid for half of repair so we had to pay $100 out of pocket. All is good to go now!

Also, if your windows stopped working from the driver door, do this:

Roll each window down halfway from the door itself. Then press and hold up to roll them up and then hold up for at least two seconds after they are fully up. Do this for each window and it will fix that issue as well.

 

Had the same issues, was starting to grow grey hair all of a sudden.

Went with the steps advised. Replaced the ECB fuse (which was blown) with the spare fuse (yes, there is a spare fuse in the box).
All is good now.
The mirror switch is permanently in the centre till further notice.
Tnx!!!

 

I am having the same problem and will try this, this evening.
Marc