FMU Compass Calibration **fixed**

Is this from the factory service manual or the separate electrical wiring diagram? The diagram I have for my 97 is much more in-depth, unfortunately I only have 97 and 99 diagrams but when I get a chance I’ll look at the 99 diagram and see if it’s close enough to yours to give any insight

I believe it's from the manual(?) I downloaded it to my tablet like a year and a half ago so I can't remember where it came from at this point. I don't see why a 99 wouldn't be close, if I recall I used a '99 ECU at one point when diagnosing my knock sensor gremlin and it worked fine
 
Last edited:
Have you rummaged around over here? Buncha 2000 manuals in there...

I did not, thank you! But upon closer inspection it just confirms the ECU pinout I have is indeed from the manual. Same exact pdf. However in there I was able to find the combination meter wiring diagram and it shows the lead going from the meter to the ECU is indeed green/orange! And checking even further, the ABS wiring diagram shows the gray/blue wire as SP1
 
Last edited:
dunno if these are the same files that were linked in a previous post


hth

They were, thanks. The combination meter pdf was exactly what I was reading, and the ECU pdf I was able to see a green/orange line from the ECU to the meter - though where is beyond me, but according to the pdf it's the only green/orange wire leading to the ECU, so if that checks out too I think it's pretty confirmed
 
I did not, thank you! But upon closer inspection it just confirms the ECU pinout I have is indeed from the manual. Same exact pdf. However in there I was able to find the combination meter wiring diagram and it shows the lead going from the meter to the ECU is indeed green/orange! And checking even further, the ABS wiring diagram shows the gray/blue wire as SP1
Is it the same as this 2000 EWD? Dropbox - 2000 4Runner Electrical Wiring Diagram (EWD383U) - Printable - Simplify your life
 
That diagram posted above is the one I was talking about, it shows the wire coming from the combination meter and going to pin 22 in plug E12, so that confirms it is the correct wire you need
 
Yes, it is the Green-Orange wire that you want to tap into, not the Gray-Blue wire. It is at:

- Gauge cluster
- Engine ECU
- Diff Lock ECU plug
- 4WD Ecu (if you have a Limited)
- Cruise control ECU (if 3rz)

I ran the FMU wires down the driver's a-pillar, so just went straight down to the diff lock plug, if I remember right... I might have tapped at the cluster though.

-Charlie
 
Thanks for the help everyone, I'm waiting on some more self soldering connectors in the mail so I'll give it a try in the coming days and see how it goes. Gonna try and use my last one later today to undo the ABS wire - really hoping that sets my speedo back, this is getting old!
 
Absolutely zero difference. Pics are while driving east and west on the same road; tried calibrating it 3 times before I left and another 4 times before taking the second picture. Tried both circles and doing the 4 right turns. Speedometer still works this time, though.
Something I noticed worth mentioning is my FMU will stop flashing after I've done maybe two or three circles, but if I hit the adjust button and don't do anything it will flash indefinitely - no "2 minute" timeout like stated in the manual. Any thoughts? This is getting really old really quick.
 

Attachments

  • Snapchat-330787521.jpg
    Snapchat-330787521.jpg
    135.2 KB · Views: 341
  • Snapchat-1193512800.jpg
    Snapchat-1193512800.jpg
    128.2 KB · Views: 343
  • Snapchat-1838298835.jpg
    Snapchat-1838298835.jpg
    126.2 KB · Views: 367
Last edited:
Parked, facing south, headlights off so the display is better illuminated (between this and the last pictures I turned off the car while parked in my usual spot before deciding to flip around and grab another picture. Because of this, you can see how the compass has shifted SLIGHTLY because I parked more directly towards NW in that time.) Green bars and L/R seem to be constantly lit up? Or is that how bright they should normally be?
The most help I've seen from Toyota themselves is "Do not perform circling calibration of the compass in a place where the earth's magnetic field is subject to interference by artificial magnetic fields (underground parking, under a steel tower, between buildings, roof parking, near a crossing, near a large vehicle, etc.) / During calibration, do not operate electric systems (moon roof, power windows, etc.) as they may interfere with the calibration." From this my only other guess would be to try it in the middle of a corn field and perhaps have my headlights off, and if that doesn't work then maybe re-do every connection?
Edit: just tried exactly that 3 more times, with both headlights and radio disabled. Nothing.
 

Attachments

  • Snapchat-143297998.jpg
    Snapchat-143297998.jpg
    128.9 KB · Views: 375
Last edited:
P0500 came back, but my speedo was still working fine :wtf:
the bars only light up in a traveling way, one after the other, not all at the same time.

Hmm. Interesting. Wonder if it's a power/ground issue maybe? Wouldn't hurt to try
 
Last edited:
P0500 came back, but my speedo was still working fine :wtf:
Ruh Roh...

Can you get live OBD-II data from the ECU? It sounds like the FMU (or how it is wired) is pulling the speedo signal to a constant voltage (high or low, likely) and now the signal isn't getting to the ECU.

So, either bad FMU or bad wiring at this point.

-Charlie
 
Ruh Roh...

Can you get live OBD-II data from the ECU? It sounds like the FMU (or how it is wired) is pulling the speedo signal to a constant voltage (high or low, likely) and now the signal isn't getting to the ECU.

So, either bad FMU or bad wiring at this point.

-Charlie

I have a real basic OBD with me but I've already cleared it, so if it comes up again on my drive home I'll take a pic of the data it gives me. What's weird is it was pretty much the same as last time - including saying I was going 0mph, when my speedometer told me I was going 40+
I'm already tinkering with the idea of getting another FMU just to help troubleshoot, and reselling it if nothing changes. Not a big deal to me, had to do that with ECUs before
I would lean towards a bad unit if it came down to it. My wiring is no different than everyone else's and it doesn't make sense how I'm the only one to have ever had problems and be vocal about it. Still, I'm gonna redo the connections when I get home. The heat shrinks I got now are wayyy better than what I had, melts way easier
 
Last edited:
I'm already tinkering with the idea of getting another FMU just to help troubleshoot, and reselling it if nothing changes. Not a big deal to me, had to do that with ECUs before
I had a bad FMU too, so you aren't alone (screen wouldn't turn on). I think they get pretty rough treatment on the way to us from the middle-east...

-Charlie
 
If your Obd scanner is showing 0mph but your speedometer works that means there is an issue between the gauge cluster and the ecu, double check the wiring at the ecu and make sure all the connections are good
 
If your Obd scanner is showing 0mph but your speedometer works that means there is an issue between the gauge cluster and the ecu, double check the wiring at the ecu and make sure all the connections are good

I get that, my point is it's clearly the splice causing it, the question is why it's happening not what is happening
If even one of the ECU's plug was loose the car wouldn't start, let alone operate totally fine in every other regard - if that was the case I could expect at least one other thing connected to that plug to be going wrong as well but that's not happening here
The actual splice pictured above looks textbook to me but if anyone has an idea on how it could be better, I'm all ears over here
 

Members online

Forum statistics

Threads
278,309
Messages
3,554,066
Members
248,016
Latest member
Advally Service

Trending content

Back
Top