Hey guys! I just changed out the stock radio in my 2010 Fit. It worked magnificently and I even turned it off, cranked it back up several times. I drove it to a friend's garage to get some help running a power cord through the wire harness grommet. I only ran the cord down under the trim after that so it's not even connected to anything yet and then went to start it to go home. It turns over endlessly but never fires up. We removed battery and air filter to try to look at the harness to see if we had cut into a wire somehow. I couldn't see any broke wires. I did check the fuses inside the car and were all good. The lights come on and radio plays, all lights and things inside work it just won't start. Radio sounds great, car won't run now lol. Do you guys think it's probably the wire harness still? Any suggestions? I am going to try putting stock radio back in tomorrow to see if maybe it hates my new radio and maybe check fuses under the hood after depending on results but the fuses on positive are fine. If that fails I may need to take it to a dealer to have them check it out. It's never not started before this point in 15 years.

Edit: Worth asking if there's any security features that are locking the fuel pump or something? I don't think a 2010 Fit w/o Nav has security like that does it? Only security I know of is if the battery is unplugged I have to put in the radio code in the stock one to get radio working, but car still runs.

Update: It's fixed now after ECM replacement.

 

Have you checked the fuse with a tester? Sometimes, they look OK but they are shot.

 

Yes, I used a circuit tester on the ones inside. I didn't test the ones at the battery except for visually.

 

It's really odd to me that it worked fine at my house. I left the negative unplugged the entire radio swap and had no issues with radio. I drove to the store and grocery a couple trips just to listen to radio and make sure car didn't do anything funny. The not starting issue only began after we pushed the cord through the firewall (it's not connected to anything yet). I won't be able to swap back to the stock radio till this afternoon to test it but I am worried about that harness more than anything to be honest. I hope a dealer can easily tell me if there's an issue there. Seems like my only option at this point.

 

Just a shot in the dark, but is there any chance that unconnected power cord might be touching some metal and shorting?

 

Thanks for the reply Vern! I am taking any advice I can get! The unconnected power isn't connected on either end. I have it looped off in the corner beside the battery. I mean it's possible the other end is touching the frame near the trim but the other end is definitely unconnected to anything. It's a real mystery right? lol.

 

Update: The Honda dealership said there are no stripped or exposed wires and they think the computer itself is fried. How would that even happen? They had no clue. I did find an old computer in another Honda at a junkyard for about 75 dollars, so I am going to try that since they said a new one would be a couple thousand dollars.

 

Looks like replacing the ECM fixed my car. They are still unsure what causes it to short out in the first place and advised me to swap back to a stock radio and said definitely do not try to add the load of an amplifier to the system or I risk it happening again. Any truth to that statement? I have seen lots of 2nd Gen Honda Fit's online with nice systems. Can you guys give me some feedback? I low key don't believe them and want to just connect the amp...but also I am scared I'll blow the ECM again.

 

If the install is done correctly, I don't see why it should fry the ECM. Unless cheap Chinese made radio?

Always safer to unplug the battery when installing electrical stuff. I never did it and never had any problem though.

 

It's an Atoto. Definitely Chinese made Android tablet radio. I thought they were good quality though. Had a few people say that they work great. Maybe they lied lol.

 

we know that modern security systems/immobilizers aren't hardwired -- keys have chips that transmit a signal (or whatever), yeah?

I've been doing some home electrical, and talking to my home security friend. learning a little about interference.. running line (power supply) wires near cat cable messes them up. He just told me the other day that they try to separate their cat cables from other electrical wires by at least 6", preferably 8" to prevent interference, and that's when they're running shielded wire (I guess they only use shielded).

I guess what I'm wondering is whether where you ran the wires for your setup caused interference for the car's ecm/immobilizer.
I know that generally, people like to make their set-ups reversible and all that (not add any additional holes), but maybe you could drill another hole in the firewall and add a grommet to facilitate passage of your wiring?

But I may be getting the facts of how the fault was triggered mixed up.

Not sure how you wired when you first did your set-up v. when the fault appeared.. but it sounds like either the set-up you ran with was a computer killer, or we have easily killed computers.

 

Thanks for the information. It was definitely ran beside the wire harness inside the grommet but another hole I made in the rubber. The issue is we didn't add power.to the power cord. The horn beeped and I think that's when the computer blew. It did it when my friend crawled under the pedals and was tugging the grommet. My key didn't make the car beep after that when I locked it. It's running fine now but still wondering if I'll have more problems. I'll update the post if I find out any more. New radio is great but covered air vents. If I have no issues for a few weeks I'll try connecting the amp power and subwoofer. You do have me wondering if I could run the power through the wheel cover instead. The tech at the dealership suggested that. I don't like the idea of drilling more holes.

 

Man, it's crazy to think that a tug fried your ECM. But it's working now, and maybe a tug fried it ~

Honestly, I get your apprehension. A little of mine went away when I helped a dude who looked, talked, and had the same name as my dad, asked for my help doing a restomod on an AMC AMX. Zero reservations about making holes, that guy..

Anyways, a grommet can be plugged -- a compromised oem wire junction cannot be perfectly un-fuckered. If you're thoughtful and deliberate (you seem plenty sharp), it could be better than using OE routing. If it ever needs removal, you won't have to sort stuff out from original wires.

Freakin Chevy Tahoe I'm trying to help with (parasitic drain) -- the dude integrated security cameras, a sub, an amp, light bars.. all with the oe harness. Even re-wrapped it all in aftermarket loom. Then, he died. And his nephew got the tahoe.
It's just a game of "come back next week and we'll try again with the amp clamp". I wish he routed his nonsense separately. And that his nephew would just remove all the crap until it's bone stock, then reinstall the mods he actually wants.

I never thought I'd be of this opinion.

 

No issues with it for over 10 days except the driver side headlight died. Suspicious since I replaced it before installing my radio. Outside of that it's working perfectly.