Kvila37

Hey guys, the screen goes blank on both the navigation and backup camera screens (although the backlight still works) on my 05 LS430, but the audio screen and climate screen work just fine. The nav button beeps like normal when you press it, but goes to a backlit blank screen. the lexus symbol pops up when starting the car, but then goes to the same blank screen. I took the ecu out of the trunk, disconnected the boards inside of it for 30 minutes, disconnected the car battery for 30 minutes, checked fuses, and took the navigation out of the console to see if anything looked strange. Nothing seemed visually out of the ordinary, except for a 1" black wire sticking out of the board. The view in the pic is as if you were holding the nav unit and you flipped it over like a book. Notice the black wire located on the green circuit board at the end of where it says "Fujitsu ten limited.". I cant see any obvious place that it would have been connected, and almost looks like its been cut. But maybe not, I don't know; i can't think of a purpose for it in its current state. Any ideas on what the fix is?

StanVanDam

Can you enter diagnostic mode? On the I Agree screen, tap: top left, bottom left, top left, bottom left, bottom right. Go to the Loading screen and try setting it to the US option. Check the other screens to make sure your firmware is loaded properly and that your nav disc reads properly. I would guess that your nav firmware somehow got corrupted.

Otherwise, take it to a Lexus dealership and get a tech to get in touch with someone in their online system that can decipher the Error Log codes.

I think that wire is just for grounding purposes during assembly/testing.

Kvila37

StanVanDam- Thanks for the reply. I am unable to see the 'I agree' screen- It goes from the Lexus symbol directly to backlit blankness. However, knowing where the english/french/I agree buttons are, I am able to press the area and select these. Selecting a language button does cause a screen to pop up that I can see that confirms the language change. When I push the area where the 'I agree' button is, it beeps, but does nothing visually......Holding the 'Audio' and 'Climate' buttons down while flicking the lights on and off 3 times brings up "service check mode." Holding the 'Options' button while flicking the lights on/off 3 times brings up "diagnosis check 1." I can't tell the difference between the two, as they both show the same information. They do, however, show different status' for the listed components. When I get to the screen that shows the green buttons, such as navigation check and backup camera check, the navigation check beeps, then goes to a black screen that has an orange rectangle in the upper left corner (pictured). I am able to push the upper right corner of that blank screen to go back to the previous menu. Anyways, attached are the pictures of all the diagnostic screens that I ran. It was showing "not connected" for the backup camera, which I most definitely have. I'm not as concerned about that as the navigation, though. My thought is that the problem is between the internal navigation circuit boards and the screen. The unit functions fully, evident by the beeps that occur when pressing the blank screens, also evident by the fact that 'i agree' can be selected, even though you can't see it. I can't imagine it being related to some connection issue between the ecu and the dash unit. Screens that work are: Climate, Radio, Option, "bluetooth not connected" notifications show visually, english/french language changes on 'i agree' screen show if you select either by pressing the area where they are. Screens that don't work: Map, Destination, backup camera, some of the menu options (such as maintenance). I ended up resetting the codes and clearing them, and all components show ok in the diagnostics, but nothing has changed. I'm at the end of my rope on this thing!

Kvila37

Here are the other pictures of the diagnostic screens

StanVanDam

The first step for most of those error codes is to verify the power source. Thoroughly check the connectors on the rear of the nav screen and make sure every wire is secured to the harness, and makes proper contact with the port. Then do the same for the nav ECU in the trunk.

If the problem still exists, then verify the multi-display's power source circuit. Disconnect connectors M3 and M4 on the display, then:
1) Measure the resistance of M3-GND (pin 10) and M4-GND (pin 12) against body ground, both should always be < 1 Ohm.
2) Measure resistance of M3-TELSW- (pin 5) vs body ground, should always be < 1 Ohm.
3) Measure voltage M4+B1 (pin 1) - M4-GND, should always be 10-14V
4) Measure voltage M4-ACC (pin 2) - M4-GND, should be 10-14V when ignition is ACC
5) Measure voltage M4-IG (pin 3) - M4-GND, should be 10-14V when ignition is ON
If any of those fail, repair/replace the harness or connector

Next, verify the AVC-LAN circuit between the multi-display and the radio receiver assembly by disconnecting multi-display M4 and radio receiver R2:
1) On the receiver's R2, resistance of R2-TXS+ (pin 5) - R2-TXS- (pin 15) should always be 60-80Ohms. If not, replace the radio receiver assembly.
2) On the R2 and M4 connectors, resistance of R2-TXS+ (pin 5) - M4-TX2+ (pin 21) should always be < 1Ohm
3) On the R2 and M4 connectors, resistance of R2-TXS- (pin 15) - M4-TX2- (pin 20) should always be < 1Ohm
4) R2-TXS+ vs body ground should be > 10kOhm
5) R2-TXS- vs body ground should be >10kOhm
If any fail, repair/replace the harness or connector.

Next, verify the Nav ECU's power source circuit by disconnecting N4 and N6
1) Measure resistance of N4-GND1 (pin 9) vs body ground, should always be < 1 Ohm
2) Measure resistance of N6-SNSE (pin 6) vs body ground, should always be < 1 Ohm
3) Measure voltage of N4-+B (pin 1) vs N4-GND1 (pin 9), should always be 10-14V
4) Measure voltage of N4-ACC (pin 10) vs N4-GND1, should be 10-14V when ignition ACC
If any of those fail, repair/replace the harness or connector.

There are a few other subsystems to verify the resistance and voltages of, but all are to find a bad harness/connector. Only 1 troubleshooting step points to a bad radio receiver assembly - maybe you can find a spare one to test with. The last step after verifying all circuits is to replace the multi-display, then to replace the nav ECU.

harro

Hello everybody!

Are there any news about this problem because I have same situation on my Lexus 400h.
Clima and Audio menus are working fine but Navigation, rear view camera, calendar, maintenance, menu and other screen are just blank. Only the backlight is working. When I press on the blank screen it beeps, so it looks like the everything is working but not shown. Also if I enter the hidden menu and select Navigation Check screen becomes black but if I press in the upper right corner where should be the back button screen beeps and brings me back to the hidden menu. So... everything works but almost
Tomorrow I'll try to check the things written in previous post and see what happens.

Cheers

Kvila37

Over a year later, I have solved this issue! There is a television camera ecu in the trunk; the signals for both the backup camera and the navigation unit pass through the television camera ecu (part # 86792-50040). The constant power wire going to this module was showing 0 volts when I tested it on the multimeter; it should be 10-14v at all times (even when the car is off). Thus, the unit that sends both signals (backup camera and navigation) to the display was not powering up. Rather than trace the wire harness through hell and back, I simply spliced into this wire at the connector and ran it to the constant power from the fuse box located in the trunk, and it works perfectly! I was able to diagnose this by subscribing to techinfo.toyota.com for 48 hours ($10 I think) and downloaded all electrical pdf's for the navigation and radio. I can post pictures of the fix if anybody is interested. With a few pics, a novice could fix this in a short amount of time. Anyways, I hope this helps.

rustednail

iTrader: (1)

I have the same exact issue. Can you please provide pics? Is the television ecu in the right side trunk next to the nav ecu?

rustednail

iTrader: (1)

I solved my problem in case anyone is having the same. There's a fuse box in the left side trunk. The 7.5 amp fuse to the television ecu was missing.

ndbethy

Hello, I came across this forums trying to find help for solving my nav problem and I believed you are my SOLUTION…. So would you please please please RE-POST the pictures of the FIXED with higher resolution? Thank you… BTW, I did pay techinfo.toyota.com $20 for 48 hours but no luck because they don’t have wiring diagram for my gx (2017 gx460)