Car Not Starting - U0100 Code: SOLVED!

[Overflow]

Hi all.

A few days ago my car would take a little bit longer to start. Did the infamous clicking noise and eventually would start. It would almost always start with the immobilizer light illuminated (Car with a lock attached). But would drive normal once started.

Took the car and swapped the battery (I still have the factory battery, figured it was dying). Still did it. Went and tested both the stock battery and new batter, and both tested good. Tested the alternator. Also tested good. So I assumed it was the starter.

Before I got to replace anything, I attempted to start the car today and the car won't start at all. No clicking or anything. But it does have battery power. It was running fine last night.

Brought out the code reader and it's only showing a U0100 code with "Service Stabilitrak" and "Service Parking Assist" on the DIC.

I have no idea what this could be.

[Rock-It Man]

Check the starter ground wire for looseness or corrosion.

[hunter1660]

Starter is my bet

[LuSINda]

Check the starter ground wire for looseness or corrosion.
^This^

You may to also want to read this:

https://www.obd-codes.com/u0100

[Overflow]

Ended up being my starter ground. Thanks all.

[Overflow]

UPDATE: When I typed my last post, I THOUGHT I had it figured out. Updating for future browsers having the same issue.

The car failed to start again, and almost left me stranded. Limped it home, and now determined (and a little frustrated), I set out to find what was wrong with the car. Had a buddy of mine watch the engine bay while I started it and he noticed sparks coming out from the bottom of the fuse box. No burnt wire and no burning smell led us to the ground of the fuse box. Loosened the ground, tightened it, and boom. No more starting issues and no more sparks.

[BAH2SS]

^^^
Glad you figured it out & thanks for the update.

[bilydean]

just so when others are searching the U0100 code. I put headers on the car and had to remove the ECM ground wire on the passenger head to get them on. Get everything installed, fired the car up drove it 6 miles away and it just crapped out. No cranking, no starting, fuel gauge read zero (and I knew that wasn't right). Towed it home. Checked battery voltage, looked for burnt wires, check all fuses, etc. Then realized the ECM ground bolt was only finger tight as I needed to go get the 15mm socket. Turned out I never returned to tighten it and get a good ground. Once tightened, the car fired right up. Can never say enough about making sure you have good grounds.

[ADVMax]

I am an old BMW 2002 nut. Those are about the most fun little car you'll ever hoon around in. Simple and reliable. Every one I ever had the first order of business was to run a dedicated ground wire from the battery negative to EVERY ground point in the car. There weren't that many. Never had one second electrical problem out of any of them. Those cars made me a believer about good ground!

[joekono]

Originally Posted by ADVMax

I am an old BMW 2002 nut. Those are about the most fun little car you'll ever hoon around in. Simple and reliable. Every one I ever had the first order of business was to run a dedicated ground wire from the battery negative to EVERY ground point in the car. There weren't that many. Never had one second electrical problem out of any of them. Those cars made me a believer about good ground!

Glad everyone is up and running. Yeah those grounds will really get you.

[Gunn]

Originally Posted by bilydean

Then realized the ECM ground bolt was only finger tight as I needed to go get the 15mm socket. Turned out I never returned to tighten it and get a good ground. Once tightened, the car fired right up. Can never say enough about making sure you have good grounds.

Hey guys, resurrecting this old thread once again as it's completely relevant to my current situation. Camaro was running just fine and then poof, wouldn't start. No clicking from the starter, no nothing. I haven't touched the car in years, other than regular maintenance. Checked and even swapped the battery. No luck. Everything electrical seems to work, lights, interior chime, dash lights, etc. EXCEPT the fuel gauge reads empty (which isn't right), just like this post.

Check engine light flashes like crazy (~5Hz) as soon as the key is turned to the ON position. Code reader shows U0100.

My question pertaining to this quote: Where is the ECM ground wire located? I've found a few, but everything looks fine so far. Nice and secure and clean.

Thanks!

Tom

[1JEWLDSSRS]

Originally Posted by Gunn

Hey guys, resurrecting this old thread once again as it's completely relevant to my current situation. Camaro was running just fine and then poof, wouldn't start. No clicking from the starter, no nothing. I haven't touched the car in years, other than regular maintenance. Checked and even swapped the battery. No luck. Everything electrical seems to work, lights, interior chime, dash lights, etc. EXCEPT the fuel gauge reads empty (which isn't right), just like this post.

Check engine light flashes like crazy (~5Hz) as soon as the key is turned to the ON position. Code reader shows U0100.

My question pertaining to this quote: Where is the ECM ground wire located? I've found a few, but everything looks fine so far. Nice and secure and clean.

Thanks!

Tom

Take a peek through this.

https://www.bing.com/images/search?q...m=IGRE&first=1

[Gunn]

Originally Posted by 1JEWLDSSRS

Take a peek through this.

https://www.bing.com/images/search?q...m=IGRE&first=1

Thanks, I poked around through there and did some more searching. I found a post where someone had a link to the 2010 Camaro Service Manual on a Google Drive. Using that, I found all of the ground wire attachment points in the engine bay. I removed all of them on the right (passenger) side either from the engine or the body/frame, cleaned them with a wire brush or wire wheel on a drill, added some dielectric grease and re-attached. Some of them were a bi&*! to get to.

G101 - Rt. front lower on body (cleaned)
G102 - Rt. front lower on body, behind G101 (under heat shroud) (cleaned)
G103 - Rt front body, larger under fuse box (cleaned)
G106 - Rt. side engine in front (cleaned)
G108 - Rt. side engine, back (cleaned)

After cleaning each one I tested with the key. Still nothing. Won't turn over with key. With key in start position, everything goes black. Then everything comes back (dash lights, radio, etc.) when the key is released.

The following show up on the DIC:
- Fuel Level Low (Fuel gauge is reading 0, even though there is 1/2 tank full)
- Open, then Close Passenger Window
- Service Tire Monitor System

I also checked all other electrical components, almost everything works (dash lights, radio, dome light, headlights, high beams, fog lights, horn, wipers, washer fluid, tail lights, brake lights, turn signal lights, trunk light). The ONLY thing that doesn't seem to work is reverse/backup lights and the fuel gauge. Clue?

I have not cleaned those grounds on the left/driver side yet. Will tackle that tomorrow There are 3:

G105 - Left side lower body (single wire)
G107 - Left side of engine, back (2-3 wires)
G109 - Left side of engine, mid (single wire)

One question I have: Where or which is the starter ground wire? I haven't found anything obvious.

Any other ideas?!

Thanks again, Tom

[1JEWLDSSRS]

Wow that sucks you're still having issues. How old is the battery, and did you check it for its state of health? Charge/load capacity? Also check your main battery ground cable in the trunk, maybe that is an issue as well. Not sure about the starter ground wire, there is only one cable going to it, the power cable. Unless it is in the plug in connection. Good luck.