Ecu harness fried after gauge install??

[eoevangelion]

Hello! I recently installed the Sirimoto flexfuel kit on my 2017 Civic hatchback touring. Straight forward just unhook the fuel lines and place in the new new ones. Tuned with hondata and the car fired up no problem. I then went to install the gauge. I followed the instructions to the best of my knowledge, disconnecting the negative terminal first, triple checking everything and reading the instructuonsi10 times over making sure the correct fuse was removed and replaced. Making sure the wire was grounded and making sure the gray #54 wire was spliced with the yellow wire on the kit. I went to start up the car and every single light was on. I mean every single one, Cel, hill start assist every vsa light, etc. The car still runs although it's in limp mode. Ran it to the dealership the other day and had a new ecu overnighted as they said it was fried. They replaced it and the problem still persists. Now they say I need a new wire harness which brings the total to 2k$. Is there anything else I can check or try before spending that money On something that may not even fix the problem? I reflashed the ecu multiple times, disconnected the battery for about 20-30 minutes. The code the flashpro shows is p2122 which is low voltage in the gas pedal. Anything I can try before I go to the dealership again? Any suggestion is appreciated !!

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[shoegazer]

Yikes. My gut feeling is that there is something wrong with the install or something wrong with the kit. Damn near *everything* on this car is electronic or is connected to a computer in one way or another. You certainly could have fried the ECU or a wire in the process (always disconnect the battery). But you could also just have a faulty component of the kit, a wrong setting in HonData, or something else that's throwing the system into Helter Skelter.

If it were me; I'd uninstall everything and see if the car will run and behave in the stock configuration. If so; presumably you have no damage to the ECU or harness.

If you want to post the instructions and photos; maybe we can spot the error.

Also... it sounds like a fool's errand; but check all the fuses. There was another thread just yesterday where the issue was a blown fuse due to a mistake in the installation. All hell was breaking loose on the dash and the car wouldn't start and 'oh shit'... we're all gonna' die, etc. It was a fuse.

Good luck with it.

 

[SCOPESYS]

Hello! I recently installed the Sirimoto flexfuel kit on my 2017 Civic hatchback touring. Straight forward just unhook the fuel lines and place in the new new ones. Tuned with hondata and the car fired up no problem. I then went to install the gauge. I followed the instructions to the best of my knowledge, disconnecting the negative terminal first, triple checking everything and reading the instructuonsi10 times over making sure the correct fuse was removed and replaced. Making sure the wire was grounded and making sure the gray #54 wire was spliced with the yellow wire on the kit. I went to start up the car and every single light was on. I mean every single one, Cel, hill start assist every vsa light, etc. The car still runs although it's in limp mode. Ran it to the dealership the other day and had a new ecu overnighted as they said it was fried. They replaced it and the problem still persists. Now they say I need a new wire harness which brings the total to 2k$. Is there anything else I can check or try before spending that money On something that may not even fix the problem? I reflashed the ecu multiple times, disconnected the battery for about 20-30 minutes. The code the flashpro shows is p2122 which is low voltage in the gas pedal. Anything I can try before I go to the dealership again? Any suggestion is appreciated !!

Dealer Tech:

Guess #1 : Fried the ECU - get a new one and replace ( serves the customer right for messing with the car - nice profit on this one .., not warranty-- we can charge what be like, easy to swap out - don;t have to do much work.)

OOPS - that did not work so

Guess #2 : Fried Harness - get new one and replace .. EVEN BETTER - Lots of labor charge here-- even more profit. Service manager will love me this week !!!

OOPS- that did not work so

Guess #3 - Fuse .. "OH.. it was a fuse after all" -- NEVER Mind, customer will never know

If they say you need a new wire harness, it should be because they can identify an issue in the existing harness... which I suspect they cannot .. it just seems like a "guess" based on what you may have done.

With everything being fuses, it's very difficult to "burn out" a harness, or to even damage it by a short .. the Fuse will blow way before any harness wire heats up enough to cause any issue.

As another member commented -- I bet it is just a $1 fuse

But Service dept is not going to stay profitable, on replacing a $1 fuse !!!

----
On a side note, ALL Lights coming on would seem to be quite a common symptom.
The guys that posted recently about replacing his Brake light has a similar symptom.. all light came on, when into limp mode. -- because he had blown a $1 fuse (maybe with a wiring error) -- but that is what fuses are for-- to PROTECT other components from damage , Put wiring error right - new fuse - all back and working.

so, to answer your question
"Anything I can try before I go to the dealership again? Any suggestion is appreciated"

Yes, re-check all the fuses -- maybe consider when you do this, as you will need to remove them to test them, to replacing them with Fuses with Test Leds in them, that light up when the fuse is blown. $30-$40 for a set of those is far cheaper than $2K+ for an ECU & Harness, that chances are, you don't need.

 

[eoevangelion]

Yikes. My gut feeling is that there is something wrong with the install or something wrong with the kit. Damn near *everything* on this car is electronic or is connected to a computer in one way or another. You certainly could have fried the ECU or a wire in the process (always disconnect the battery). But you could also just have a faulty component of the kit, a wrong setting in HonData, or something else that's throwing the system into Helter Skelter.

If it were me; I'd uninstall everything and see if the car will run and behave in the stock configuration. If so; presumably you have no damage to the ECU or harness.

If you want to post the instructions and photos; maybe we can spot the error.

Also... it sounds like a fool's errand; but check all the fuses. There was another thread just yesterday where the issue was a blown fuse due to a mistake in the installation. All hell was breaking loose on the dash and the car wouldn't start and 'oh shit'... we're all gonna' die, etc. It was a fuse.

Good luck with it.

I'll scan in some copies of the instructions later on tomorrow. I bought a little pen that you use to check the voltage/current for the fuses and I didn't find any that were blown. I even pulled them out and shined a light through them to see and I didn't find anything.

 

[eoevangelion]

Dealer Tech:

Guess #1 : Fried the ECU - get a new one and replace ( serves the customer right for messing with the car - nice profit on this one .., not warranty-- we can charge what be like, easy to swap out - don;t have to do much work.)

OOPS - that did not work so

Guess #2 : Fried Harness - get new one and replace .. EVEN BETTER - Lots of labor charge here-- even more profit. Service manager will love me this week !!!

OOPS- that did not work so

Guess #3 - Fuse .. "OH.. it was a fuse after all" -- NEVER Mind, customer will never know

If they say you need a new wire harness, it should be because they can identify an issue in the existing harness... which I suspect they cannot .. it just seems like a "guess" based on what you may have done.

With everything being fuses, it's very difficult to "burn out" a harness, or to even damage it by a short .. the Fuse will blow way before any harness wire heats up enough to cause any issue.

As another member commented -- I bet it is just a $1 fuse

But Service dept is not going to stay profitable, on replacing a $1 fuse !!!

----
On a side note, ALL Lights coming on would seem to be quite a common symptom.
The guys that posted recently about replacing his Brake light has a similar symptom.. all light came on, when into limp mode. -- because he had blown a $1 fuse (maybe with a wiring error) -- but that is what fuses are for-- to PROTECT other components from damage , Put wiring error right - new fuse - all back and working.

so, to answer your question
"Anything I can try before I go to the dealership again? Any suggestion is appreciated"

Yes, re-check all the fuses -- maybe consider when you do this, as you will need to remove them to test them, to replacing them with Fuses with Test Leds in them, that light up when the fuse is blown. $30-$40 for a set of those is far cheaper than $2K+ for an ECU & Harness, that chances are, you don't need.

I appreciate everything. I saw that post when I was looking to see what the issue was. I checked every colored use with a current/volatge pen from the hardware and even manually pulled out the fuses and couldn't find a single one that was blown. Ended up taking it to the dealership and they replaced the harness but even that didn't fix it as expected so they're contacting Honda of America to "help them with the ticket". I didn't have to pay for the work. . . . For now.

 

[eoevangelion]

I only checked the fuse box in the engine bay I completely forgot there was one inside the cabin as well. Going to check those asap.

 

[eoevangelion]

Just checked all of those and didn't find a blown fuse in there

 

[shoegazer]

Hmm... even though the fuses were all good; it's the first place to start and the first thing to rule out. So no wasted effort.

I'f I had to guess; I'd suspect that your wire splices are to blame. If you're 100% sure that you used the correct wires; I'd look for any shorts, exposed metal, wayward wire strands, etc... that may be shorting out. Alternately... it's entirely possible that one of those splices actually severed a wire in two and the original is now disconnected. Or the splice failed to connect on one of the wires and the car is now upset with the other oddball connection.

Just thinking out loud. I hate those splice thingys.

 

[SCOPESYS]

Hmm... even though the fuses were all good; it's the first place to start and the first thing to rule out. So no wasted effort.

I'f I had to guess; I'd suspect that your wire splices are to blame. If you're 100% sure that you used the correct wires; I'd look for any shorts, exposed metal, wayward wire strands, etc... that may be shorting out. Alternately... it's entirely possible that one of those splices actually severed a wire in two and the original is now disconnected. Or the splice failed to connect on one of the wires and the car is now upset with the other oddball connection.

Just thinking out loud. I hate those splice thingys.

So , Dealer Tech's - "Guess #1" and "Guess # 2" were both wrong.
Big Surprise !! I would have put money on those guesses being wrong


Not having seen the Install Instructions for the after market device you installed, it's difficult to imagine what it could be doing to cause your issue, if in fact, it is the current cause.

Have you tried removing those connection to your device, and returning the car's wiring back to it's original state ?

(To be honest (or should I say "Not Honest") - I would have removed that add-on BEFORE even going to the Dealer, and would not have mentioned it to them - and still been able to sleep at night )

I would still fit those Indication Fuses.. just so you can easily monitor their states at any time.

Your addon device must have spliced into the +12v Power line, probably onto a fuse line that is turned on by the ACC+ (it Not direct to the battery, and on ALL THE TIME). A lot of those ACC+ lines come through relays .. you might have a bad relay / relay contact damaged by a past temporary short with your addon wiring, so may not be a fuse.

Measure ACC+ (12v) Voltage at the point you spliced into the wiring.

IF you don't have a meter -- get one... you can get an adequate Digital Meter from Harbor Freight, or if you get a coupon, you can get one for FREE, when you buy something else, like a $0.95 bag of zip-ties !!

Dealer must be pretty frustrated-- down about $2k+ and still not fixed.
You will be doing VERY WELL if they end up treating it as Warranty, as it seems reasonably clear, that it was something you did to CAUSE this issue, even if at the moment, you and the Dealer cannot determine what is causing the issues.

Going to be most interested to hear what they end up finding is causing your issues .

Maybe you could post the Install Instructions .. looking at that, and the Car's wiring schematics, might throw some light on things - at least it would indicate where you should be looking for what appears to a a "Lack of voltage" -- Ref: The OBD2 error code about Low voltage.

 

[latole]

Dealer Tech:

Guess #1 : Fried the ECU - get a new one and replace ( serves the customer right for messing with the car - nice profit on this one .., not warranty-- we can charge what be like, easy to swap out - don;t have to do much work.)

OOPS - that did not work so

Guess #2 : Fried Harness - get new one and replace .. EVEN BETTER - Lots of labor charge here-- even more profit. Service manager will love me this week !!!

OOPS- that did not work so

Guess #3 - Fuse .. "OH.. it was a fuse after all" -- NEVER Mind, customer will never know

If they say you need a new wire harness, it should be because they can identify an issue in the existing harness... which I suspect they cannot .. it just seems like a "guess" based on what you may have done.

With everything being fuses, it's very difficult to "burn out" a harness, or to even damage it by a short .. the Fuse will blow way before any harness wire heats up enough to cause any issue.

As another member commented -- I bet it is just a $1 fuse

But Service dept is not going to stay profitable, on replacing a $1 fuse !!!

----
On a side note, ALL Lights coming on would seem to be quite a common symptom.
The guys that posted recently about replacing his Brake light has a similar symptom.. all light came on, when into limp mode. -- because he had blown a $1 fuse (maybe with a wiring error) -- but that is what fuses are for-- to PROTECT other components from damage , Put wiring error right - new fuse - all back and working.

so, to answer your question
"Anything I can try before I go to the dealership again? Any suggestion is appreciated"

Yes, re-check all the fuses -- maybe consider when you do this, as you will need to remove them to test them, to replacing them with Fuses with Test Leds in them, that light up when the fuse is blown. $30-$40 for a set of those is far cheaper than $2K+ for an ECU & Harness, that chances are, you don't need.

 

[latole]

Just checked all of those and didn't find a blown fuse in there

You know how for sure?

 

[SCOPESYS]

Just checked all of those and didn't find a blown fuse in there

DO you know for sure that the Dealer's Tech checked all the fuses ?
Takes a little time & effort .. it's so much easier to just plug in an OBD2 device and blindly follow what it reads !!!

 

[eoevangelion]

DO you know for sure that the Dealer's Tech checked all the fuses ?
Takes a little time & effort .. it's so much easier to just plug in an OBD2 device and blindly follow what it reads !!!

When I took it to the dealership I decided to leave it in. That way they would know what was done and would have an idea of how to fix it. The first thing I did was remove it after the first initial visit though. Infact when they installed the new harness it came with a new wire and that's never been touched or spliced so it isn't anything to do with the install anymore. They said since all the aftermarket parts are gone the car is back under warranty. The car is bone stock now with a new ecu and harness and the problem still persists. I bought new fuses and fuse checker from harbor freight and check every fuse in and out and couldn't find a thing. I'll post a copy of the install guide and what I did tonight.

 

[SCOPESYS]

When I took it to the dealership I decided to leave it in. That way they would know what was done and would have an idea of how to fix it. The first thing I did was remove it after the first initial visit though. Infact when they installed the new harness it came with a new wire and that's never been touched or spliced so it isn't anything to do with the install anymore. They said since all the aftermarket parts are gone the car is back under warranty. The car is bone stock now with a new ecu and harness and the problem still persists. I bought new fuses and fuse checker from harbor freight and check every fuse in and out and couldn't find a thing. I'll post a copy of the install guide and what I did tonight.

Did you get the "Illuminating when blown" fuses ???

When you post the Install guide.
I think I can lay my hands on a copy of that harness's wiring diagram, and if so, can trace your added wiring back through "whatever" to the battery.

Back under warranty .. but "what warranty" -- read the small print.
The ORIGINAL parts were under the original factory vehicle warranty.
Any replacement parts (warranty or not) are normally under their own new warranty, which is a lot less than the Original part's Factory warranty.

A little detail that they may have "conveniently forgotten": to tell you.

The Dealer Installed it, so yes, there IS a warranty, but it may not bet covered under the original (longer) warranty .. You cannot win with the Dealer - they hold all the cards - that's why they are called DEALERS !! You certainly don't get "DEALS" from them !!
Always an ACE up their sleeves..

 

[eoevangelion]

Here are the instructions. Might have been something with the fuse box or the gray wire 54 not being connected properly.