ECM 1 Fuse keeps blowing

[Mikeysjr]

Sit back and get comfortable I got a bit of a story to tell you guys.

I own a 2002 Chevy Tahoe 5.3 4WD. One day I was driving to work and my car decided to just die on the freeway. I got off to the side of the freeway and tried to start it. The truck made clicking sound like it wanted to start but wouldn't. On my third attempt to start it, the gas meter went down to E. After that it would not make the clicking noise anymore.

I had it towed to my house and a mechanic took a look at it and replaced my battery and alternator. He blamed my amplifier for killing my battery even though I've had the amp there for more than a year with no problems. He removed the wire from the battery to the fuse and said everything should be fine.

So I drive it to my dads house and it seems fine, but as I am driving back home the truck stops in front of a dealership. A man approaches me and tells me to check the fuses. Sure enough my 10A ECM 1 fuse was blown. I replaced it with another 10A and it started up and took me only about a mile before it blew again. So I pushed it off to the side and called a friend and he said to put a 20A fuse, and I was able to make it home. He told me to just leave the 20A in and I would be fine.

Next day I drove about 20 miles to work and was at a red light. The light turned green and I hit the gas and my truck died. I pushed it to the side and replaced the 20A it with a 10A. It started and I shifted to D and hit the gas and it blew. So I put a 20A and was able to make it to work. I had it towed again to my house.

I googled a bunch of stuff and people said it could be fuel pump or wiring. So my dad and I were checking the wiring. I found some wire that was exposed but not ripped from what I could see. My dad put the car to ON and I started messing with the wire to see if it would blow a fuse. At the same time my dad was tugging the wires in the engine. The fuse didn't blow so we tried starting it. This time the car just made the clicking sound like it wanted to start. The fuse would not blow and the car would not start. I'm not sure what we did but my guess is we unplugged something while pulling on the wires. It got late and cold so we decided to quit and that's were I am now.

So what do you guys think the problem is and how much you think this is gonna cost me to fix? (Sorry for writing so much I just wanted to share everything that happend to me.)

 

[Freedom Motorsports]

Welcome to the forum!

honestly, it sounds to me like you may need to unplug the harness from the ECM, then go through all the wiring to check for weak spots as well as moisture. You could have a wire in the harness that has separated inside it's sleeve or you could have a wiring that is chaffed and grounding somewhere that it shouldn't.

Another thing to try would be to double check the grounding cables at the batteries, sides of the engine, starter, etc to ensure that all the leads are clean.

One other thing that is possible but rare; I have seen some trucks have damage to the wiring UNDER the top section of the fuse block under the hood. Carefully pull that top piece off and make sure nothing has made a nest in there. I have seen this happen in the past and it can obviously cause issues.

These are just suggestions, but also consider this a free bump to the top for others to help with their suggestions as well...

 

[crazyikon86]

this is gonna be hard to find. its not a short to ground causing it to blow. its something pulling more amps then the fuse/system allows. if i can get a wiring diagram and see whats all on that circuit. post it and ill help you. you said the pump is on there, if its going back could cause more amps to pull.

 

[Mikeysjr]

Thanks for the replies. So the truck started this morning and it died after putting it into drive. I found my code reader and it gave me the codes P0179 and P0178.

 

[Freedom Motorsports]

Those codes have to do with the fuel composition sensor. If you look on the drivers side, inside frame rail, about midway, you'll see the fuel filter. Follow that line up towards the front of the truck and you'll see that the fuel filter outlet goes right into the sensor (silver square box, two fuel lines and an electrical plug). Double check the wiring for damage, but also check the plug to ensure that it is good and dry. Then put some di-electric grease on the connector before reconnecting and then test. If the wires and connector are OK, then you probably have a bad sensor.

This will not usually cause the engine to shut off, but that should solve those two codes.

 

[Mikeysjr]

Those codes have to do with the fuel composition sensor. If you look on the drivers side, inside frame rail, about midway, you'll see the fuel filter. Follow that line up towards the front of the truck and you'll see that the fuel filter outlet goes right into the sensor (silver square box, two fuel lines and an electrical plug). Double check the wiring for damage, but also check the plug to ensure that it is good and dry. Then put some di-electric grease on the connector before reconnecting and then test. If the wires and connector are OK, then you probably have a bad sensor.

This will not usually cause the engine to shut off, but that should solve those two codes.

WOW thank you I found the wire. I was just going to put electrical tape on it but it looks pretty bad. How should I fix the wires?

 

[Freedom Motorsports]

First go to the auto parts store if you don't have any and get some inline splicing connectors for the proper gauge wiring. If in doubt take a small piece of wire with you and they will be able to help you get the right connectors. You will also need enough heat shrink to cover all of the wires that you will be splicing.

Remove the wire loom surrounding the wiring, then, go step by step through each individual wire and remove the damaged portion of the wire "casing" (the colored part of the wire). Then with the bare wire exposed, trim as needed to allow just enough of that exposed wire to be inserted into the inline splice connectors you purchased. Slide on a piece of heat shrink over one of the two pieces you are splicing back together and far enough back to be out of the way. Insert, crimp (crimp with a proper set of wiring pliers, if you don't have some, get some, it won't be the last time you use them I'm sure.). Once the inline splice is secured and crimped tight, slide the heat shrink over the connector splice and hit it with a lighter to shrink it around the wire and splice.

Do NOT attempt to cut all the wires at one time, you could get yourself into a mess of trouble if you connect things back up wrong. Take your time with each individual wire and you should be ok...

---------- Post added at 09:28 PM ---------- Previous post was at 09:27 PM ----------

PS: Once you have gone all the way through the individual wires, replace the outer loom and it wouldn't hurt to tape that loom from one end to the other as far as you can get to and then find a place to zip tie to to reduce the risk of rubbing again....

 

[briansoto]

I had the same exact issue on my 2000 cadillac escalade and it seems to be around the same area on all 2000 chevy's!

After my truck randomly died on me, i towed it home.
I changed the fuel pump thinking that was the issue and unfortunately is wasn't. I decided to check my fuses and sure enough my ECM-1 20A fuse blew. I replaced it and it would keep blowing them when i turned the key to on.

So i decided to google the issue, and yup seems to happen to all 2000 Chevy SUV's

Came across your post and decided to check all my wiring to crank sensor, power steering pressure sensor, and ground location. AND YUP i found the problem!

https://www.youtube.com/watch?v=z9F6xAdADLc



I disconnected both sensors and removed the ground bolt to fix the wiring...



ALL SIX CABLES WERE TOUCHING!!! WTF


ONCE I PROPERLY FIXED ALL THE WIRES MY TRUCK TURNED ON!!! ))




I RECOMMEND EVERYONE WITH THE SIMILAR ISSUE TO CHECK THIS SAME EXACT WIRE & LOCATION AS IT SEEMS TO BE THE ONE THAT FAILS THE MOST

watch this youtube video to get an idea of the location
https://www.youtube.com/watch?v=z9F6xAdADLc

 

[JonnyTahoe]

Good to know, thanks for the pic's they help alot.

---------- Post added at 11:52 AM ---------- Previous post was at 11:48 AM ----------

this is gonna be hard to find. its not a short to ground causing it to blow. its something pulling more amps then the fuse/system allows. if i can get a wiring diagram and see whats all on that circuit. post it and ill help you. you said the pump is on there, if its going back could cause more amps to pull.

It would appear it was a short issue.