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7th gen Trouble shooting Multiplex Control - inspection connector T1 & T3? [solved]
Hello all
I'm in the middle of trying to troubleshoot the Multiplex control system according to the manual page 22-273 but I'm having a spot of bother figuring out what the workshop manual means when it refers to "inspection connector T1 and T3 terminals"
I've searched the manual and the only time it mentions these terminals is on this page ... please tell me what I'm missing!
All help is much appreciated!
Car is a 2002 Gli 4 door rhd auto.
screenshot of manual page 22-273 I'm having trouble understanding step 6
Last edited by buzzbomb100; Mar 24, 2021 at 08:13 AM.
Re: 7th gen Trouble shooting Multiplex Control system - inspection connector T1 & T3?
It is asking you to check for continuity between T1 and T3. "T" is referring to a connector, 1 and 3 are the cavities in that connector. I have searched through the service manual I have and cannot find what connector "T" is, all I can tell you is that it's on the multiplexer.
Re: 7th gen Trouble shooting Multiplex Control system - inspection connector T1 & T3?
Originally Posted by BrotatoChip
It is asking you to check for continuity between T1 and T3. "T" is referring to a connector, 1 and 3 are the cavities in that connector. I have searched through the service manual I have and cannot find what connector "T" is, all I can tell you is that it's on the multiplexer.
BrotatoChip thanks so much for your reply...
I trawled the manual wiring diagrams for the multiplexer, and found that T1 and T3 are in fact the terminals that you short to get the multiplexer to blink it's dtcs. The info doesn't come up in searches because the text is embedded on the image.
I got the multiplexer to enter it's diagnostic mode (cabin light on for 5 seconds followed by the .2 seconds off and .2 seconds on. After that the light went blank and didnt flash any codes.
I then checked for continuity between T1 and T3 and there is zero continuity ( multimeter reading OL ).
It was at this point I decided the multiplexer must be toast. (That's what the manual says, anyway.
Ordering a new one fingers crossed it solves my problem (dead gauge cluster - lights up but no gauge signals, no odometer etc) previous owner replaced cluster but did not fix the problem.
Cheers for your input. Hopefully my post helps someone in the future who is scratching their head over this like I was
Re: 7th gen Trouble shooting Multiplex Control system - inspection connector T1 & T3?
Originally Posted by BrotatoChip
It is asking you to check for continuity between T1 and T3. "T" is referring to a connector, 1 and 3 are the cavities in that connector. I have searched through the service manual I have and cannot find what connector "T" is, all I can tell you is that it's on the multiplexer.
Well
I got a good one from a wrecker (couldn't find a new one) and it hasn't solved my problem (tacho Speedo fuel gauge and temp gauge still not working). But it also doesn't have continuity between T1 and T3 so I'm stuck here wondering if theres a mistake in the manual or if I have another bad under dash fuse relay box. This is so frustrating
Re: 7th gen Trouble shooting Multiplex Control - inspection connector T1 & T3? [solve
Originally Posted by sdaidoji
ouch
then a rodent chewed some of your wires somewhere
wouldn't I get some form of a error code out of the multiplexer if that was the issue? I checked the data line from the gauge cluster to the multiplexer it was ok. Also checked all the earth's and they seem ok. I have been working with the assumption that the gauge cluster is okay, because it has been replaced before and no change to the problem. It was an intermittent fault that got worse with time(sometimes the dash would work, sometimes it wouldn't) and now it never turns on
Re: 7th gen Trouble shooting Multiplex Control - inspection connector T1 & T3? [solve
Originally Posted by sdaidoji
well, that sounds like a wire or connector about to break that ended up broken...
I wish it was that simple... It would turn on and work perfectly sometimes and then other times it wouldn't work at all... If it were a broken wire I would have expected it to drop in and out while driving, which it never did. I am going to have another look at the manual and trace all the wires coming out of the dash and test for continuity where they terminate... Going to be a bit of a bother. I do suspect however that the "new" micu I've got is actually a dud.
I just want to get this fixed, it isn't even my car it's a friend of mine and usually I'm pretty good with fixing cars buy this problem has me a bit stumped. Would be nice to know if anyone here has experience diagnosing the multiplexer on these Honda's who could give me a definitive way of knowing whether the one I have is a dud or not. By my reckoning of what the manual says, it is..
Re: 7th gen Trouble shooting Multiplex Control - inspection connector T1 & T3? [solve
There's always the option of taking it to the dealership and letting them troubleshoot.
You did follow the steps up to the point of checking continuity, correct? Key on, enter self diagnostic mode 1, then check continuity between T1 and T3. If no continuity, bad multiplexer.
Also, what's the actual issue with the car? If it's just fuel and temp gauge not working those are common symptoms of a loose alternator and possibly fried ECU.
