Scan tool won't connect plus much more...

iWANNAsiR

Well-Known Member
27
23
Kingsland, GA
Vehicle Model
Civic Si
Body Style
Coupe
So I bought my 2012 Si with 3 original miles, still in the wrapper. Now I am just over 5000 miles and I ran into a bunch of electrical issues, hopefully one issue with many symptoms. My car is a rebuilt flood car from Hurricane Sandy, all work was done by myself, with an exception of the programming of things the dealer had to program. All electrical items were replaced with new OEM parts except all sensors, the airbags, the ECU and the three displays. Everything worked until now so I believe one issue is causing all symptoms. Car runs and drives fine here are my symptoms:
-Unable to connect scan tool, $200+, Advance Auto Parts scanner, worked with car before I can check the exact model later.
-A/C stopped blowing cold.
-Speedometer and tachometer do not work. Tach will move a bit if I operate sunroof or windows and then will go back to 0rpm.
-Steering! Light is on.
-Tire! Light is on.
-Stability/Traction control Light is on.
-Coolant C Light is on.
-BRAKE Light remains on even after E-Brake is released. Cruise Control won't work, which I assume are directly connected.
-ABS Light is on.
-CEL Light is on, was on before due to P145C (Evap code).
-Airbag Light is on.
Currently the interior is torn back down to just wiring, displays, and the metal structure (I was checking all grounds, all are clean and tight).
Any help would be appricated.
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I had a buddy of mine with an 8th gen that this sort of issue happened to him recently. I would say, find that tool that was able to scan your vehicles codes from Advance. My mechanic who is a Honda Master Tech basically would repair or replace things as he came across items non responsive, you are able to send signals to certain computers and modules through that scanner. If the computer or module pings back you know you are good, if you get no response, then there is a problem. It would be even more helpful if you knew someone else with a 2012 civic si that could lend you parts to swap to save you cash. We winded up having two of our other friends with 8ths drop their cars off for swaps on more expensive parts to make sure they didn't need replacing.

my friends repair bill came to the range of a bout $4,000.00. Replaced a few computers and a bad 02 sensor along with some questionable wires. I am not sure how much this helps, but I do wish you the best of luck and keep us updated.
 
just looking at that makes me want to cry. I wish I could be of help. Hopefully you get it resolved.
 
Id check the connections at your fuse boxes, then ecu and is wiring. Outside of that only other thing I can think of is backfeed/malfunctioning wiring harness
 
the fact that the tach moves with the window switch tells me its definitely some sort of wiring issue. check the fuse box for corrosion and chaffed wires. check the whole harness. honestly its hard to just give an answer since this is a unique issue. its not like we have seen this same issue 10 times. best way to go at it is check ALL the wiring
 
I haven't messed with the wiring to much so far... I have disconnected and reconnected everything inside of the car, no change, now I am off to the engine bay. All wiring looks good, as it should, because it is essentially brand new (Just over 1 year old and 5k miles).
Also today the car decided it wanted to go into limp mode.
Thank you for the replies.
 
Yea I'd suggest the same thing as @ClearCutSi and see if a scan tool will communicate with the modules but that requires it to connect. I would check to see if you have power and ground at your DLC connector, if you know that's good and the scan tool wont connect at all then you might have a CAN network wire failure or multiples somewhere that isn't sending proper signals. The fact you stated it went into limp mode the other day has me suspicious of the ECU as well. If it's the original it's possible it got corrosion internally from being in the engine bay during the flood damage, and could be the cause of all these issues. Good luck man!
 
ECU is what I am hoping they are only $300ish dollars new + a bit for programming. I own the scan tool that I mentioned in my first post, so it is the same one that won't connect that previously would. I will check the DLC stuff also, trying to do some research on the DLC... What pins are power and ground?
 
As much as it may suck to say this but I'd pay for the online manual access you can get through Honda online. I saw it around here somewhere. You can get any info you need for the car, I have access to All Data at my shop so I can look for any diagrams to help you if you can't find any info before then. It's pretty standard across all cars though for DLC wiring, hence generic scan tools. Common cause for no power at the DLC (if you have that concern) is a blown power port/cigarette lighter fuse as they usually share the same fuse.
 
Thanks for all of the data... I think my neighbor has All Data access, so I will try that first. We will see where this gets me.
 
Thank you Darkout for the comment, "It's pretty standard across all cars though for DLC wiring, hence generic scan tools. Common cause for no power at the DLC (if you have that concern) is a blown power port/cigarette lighter fuse as they usually share the same fuse." That made me think of something to check and that was the armrest power port/lighter. I use the the front one but never the armrest outlet. I verified all fuses, which are good, tomorrow I will pull the seats and carpet and check the floor harness grounds. Tonight I pulled the front bumper and verified most if not all of the engine bay grounds.
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Your definitely going about everything right. Flood/water damage is the hardest to fix since you never know what has been damaged compared to physical look. Whether or not you can get access to All Data ill look it up tomorrow myself and if you don't need it so be it lol. Honestly if you say all fuses are good and can't see a bad or faulty wire anywhere, that ECU is my target. None the less ill make a note to myself to check that for you.
 
All grounds have been verified all fuses have been verified. I am about out of ideas, this coming up weekend I think I have a tech willing to help out a bit. I currently do not have access to ALLDATA, anyone has any troubleshooting ideas/paths, post away.
 
Let's start with the scan tool bit first. How EXACTLY does it not work. Most aftermarket code readers come with a battery to allow the scan tool to operate at any time. A primitive way to check power and ground indefinitely is to hook up a scan tool that has no battery so it must use the vehicle to turn on. If that works and you get no communication to the ECU that you say you have NOT replaced, I'd say bingo we have a winner. It is located in the engine bay that was very likely water soaked during the flood and even though it may have dried out enough to work for sometime, I bet there is possible corrosion developed over time. The reason for this is most cheaper aftermarket scan tools use the factory ECU as the main computer it communicates through to show CEL lights so if it won't communicate through the CAN network and the wires are known good then your ECU(PCM or whatever) is bad. There's a certain amount of resistance the CAN wires should have when Ohm'd connector to connector, not sure what it is though. Honestly the Honda factory manual SHOULD have all these trouble shooting tips for can networks and ECU communication. I'll recommend again
the online honda thing is here -
https://techinfo.honda.com/rjanisis/logon.asp

daily/monthly/yearly access. If you can plan it out and download a ton of stuff, you may be able to get everything you need in a day or whatever.

the helm electrical manual is $110

I'm assuming all this as you haven't replaced the ECU yet. I remember you knowing prices and stuff/thinking about it.

Side story, my Toyota dealer had a brand new Rav4 get hit through the windshield by lightning (i'll see if I can get the pics) and had like 15-20k in computer/interior/wiring and just about everything else inside. It was nuts looking and the crazy part was the dozen or so cars around it had module failure. Basically to fix all of them we had to plug the scan tool up and see which modules would not come up on the network and replace it. In theory this is a similar case so I hope I'm helping.
 
I have been to cheap/lazy and holding hope that my friends at Honda will come through with the computer access/factory scan tool. From what I understand there scan tool has a much better likelihood of connecting due to its redundancy. My scan tool has no battery and does turn on upon being plugged in. It displays a communication failure after it powers up, you have selected the vehicle, and you try to display data stream, CEL's, etc. I have not replaced the ECU yet, I want to verify, with a decent amount of certainty, that the ECU is the problem and have someone lined up to reprogram the new one before I buy a new one. I have never had much issue accessing the dealers technicians after hours until this issue, before everyone was just excited for side money. It seems everyone there is afraid of this issue/just doesn't want to deal with it. This weekend I have something lined up with a buddy that work at another shop that has the Honda scan tool and computer access. If he falls through I will suck it up and buy a pass to the interwebs.
 
From what you just told me there buddy is proof in my mind as a tech (without hands on diag) that your ECU has let it's magic smoke out and called it quits. It's very simple steps for the scan tool to read the car. Does the scan tool get power, are the CAN bus lines integrity ok to send signals (that's from the DLC to the module and any wires/splices/connectors along the path between) and then it's up to the module itself to respond. The factory scan tool benefits only once you have access inside the module. The only bonus with the factory scan tool prior to access is you can check the whole network and see every module and if each individual module has chimed in. If your scan tool wont connect chances are it wont connect and if no connection then no fancy factory scan tool parameters. It's like an A,B or C thing here and if two things are known good then there's not much else to look for. Going into a flood car with the thought of cheeping out would not be my first thought.
 
So I bought a new Honda ECU... when I installed it, the car would crank but not run. This was my expectation going into this, as the ecu had not been programmed. The thing that I did not expect was the scan tool would still not communicate. Is this normal? I would not think it has to be programmed prior to connecting, but that is beyond my skill set.
The only place I have, in my opinion, cheaped out is on the diagnosis of this problem (And all labor which was done by myself to this point). I have tried utilizing all my automotive friends knowledge and their scan tools (I tried the machine they use at Lexus as well as other not Honda scan tools) and I have done this because I didn't want to pay out $5000 for someone to guess and replace modules and wiring harnesses. If there tool would give them something above what everyone else sees I would/will go to them. I have tried ALLDATA and it is useless without a CEL code. Does Hondas Service Information System give me more/better info than ALLDATA?
 
Since the immobilizer/key code isn't programmed/matched to the ecu, I'm actually surprised it'd even crank quite honestly. I'd think that has to be your next step, but others may have better advice. Do you have a way to tie the ecu and key security together?
 
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