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2000 Honda Insight
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Discussion Starter · #1 · (Edited)
There are so many threads here about the bigger ground straps between the body and the drivetrain, but not much mention of the ground for the ECM/MCM/BCM. It's on the cylinder head, between the valve cover and the MAP sensor. Mine left me stranded. Check yours now!

I was getting a flickering check engine light all day. Not flashing, just random flickering. Then it was mostly on. Still running normal. I shut the engine off at a light (no IMA or autostop). When I tried to restart the engine, it just cranked without firing. Luckily I was able to push the car into a well-lit parking lot. Fuel pump was not coming on. I checked fuses, relays, fuel pump wires, etc. Nothing seemed wrong. The big grounds were OK and everything else on the car was working. I even had someone bring me my spare ECMs to try. I gave up and towed it home.

I eventually got it to start in my driveway. I was getting all kinds of random trouble codes that didn't make sense. Something led me to the G101 terminal on the cylinder head. It has three wires on it. One wire broke off when my finger touched it, and another wasn't much better. The third wire took some effort to break.

Of course the copper wires were corroded when I stripped the insulation off. They needed to be cleaned before replacing the terminal. I read that vinegar and salt will clean the copper, and rinsing with baking soda dissolved in water will neutralize the acid. I also sprayed the wires with WD40 before putting the new terminal on. I used a waterproof heat shrink crimp terminal.

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spare ECMs
Yep. Plural, even. ROFL

You are a true Insight owner/mechanic.

My hat is off to you for figuring this out. I'd like to know how you managed to figure out that it was the ground connection, well hidden under that cover (if you don't run around with yours removed). I don't think there are diagnostic steps in the Service Manual for "car won't start, many codes and things generally gone haywire"!
 

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2000 Honda Insight
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628 Posts
Discussion Starter · #4 ·
I don't have the engine cover on. I had to move the IMA bypass Arduino ground wire a few months ago to get rid of a P1644, so I had been meaning to look at G101 anyway.
 

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Thanks, it looks like in the first picture there are two wires together and then the third wire is separate. When you redid it the crimp, you combined the three wires into one?
 

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2000 Honda Insight
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628 Posts
Discussion Starter · #6 ·
Thanks, it looks like in the first picture there are two wires together and then the third wire is separate. When you redid it the crimp, you combined the three wires into one?
Yeah, I just put all three wires in the one terminal.
 
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There is also a ground wire in the drivers side front wheel well
That same ground exists behind the passenger fender too... much easier to access with the fender off. Used both when I put in the JDM side markers.
 
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