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Discussion Starter · #1 ·
I’m thinking coolant got into my ficm and fried it. The coolant hose connector busted last night. This afternoon I changed the fitting and started the truck up. Ran fine for 30 seconds and died got u1800 code. Will not start. Also when I plug my autocal into the obd2 it’s not coming on. I also left it plugged in by accident over night bc I had been driving around checking fuel rail pressure. Went to do a boosted launch to get the desired pressure up and that’s when the hose let go. . Could weak batteries be causing this?
 

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Help please my truck has been down for a week. It won’t even start at all now
The trouble code U1000 is a vehicle specific code primarily found on Chevrolet, GMC and Nissan vehicles. It refers to a "Class 2 communications failure." ... The electronic control unit (ECU) which is the primary computer on the vehicle is unable to communicate with a module or a series of modules.

Good Luck, you haven't told us anything else about your truck, have you?
 

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Discussion Starter · #6 ·
Thanks I have access to google too. The engine wiring harness is the same on these trucks no matter what the mods are. This is a miscommunication with the FICM. Looking for someone who may have tracked down their shorted wires
 

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Discussion Starter · #7 ·
I just got the truck to run as long as I kept giving it fuel. It will idle smooth but I don’t know how long so I kept mashing the pedal every few seconds. Runs great, idles great and then it just dies and gets harder to crank every time only code I have now is U1800 again
 

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Let’s start all over again with the busted coolant hose.

You were concerned about the FICM at first, but since the engine did run temporarily, I guess you have ruled out failure of that unit.

Many an LB7 has probably been pressure washed and survived (although probably not a good practice) so a good PW soaking should not necessarily be a disaster.

Coolant at 180F+ is another story and at the risk of insulting your intelligence, have you pulled all connectors in the disaster area and used WD40 (Water Dispersant/40th formula, developed for NASA) to ensure everything is dry and sound?

What else is in the area of the coolant that may have suffered? How many times, after repairing a problem, have we discovered something that should have been obvious with a thorough visual inspection, but was simply overlooked (in my case multiple times :( ).

In post 6 you asked for advice from others who have experienced this issue, and no one responded. As a google user you apparently searched your symptoms thoroughly (and frankly, I sometimes have better luck on a straight google than using even advanced search here) but that being said I don’t recall reading of your particular set of issues.

Also, double check everything you came in contact with when you made this recent post: “Code 0090 no power and SES”. Can’t be too careful :).

And finally, sigh...

407driver deserves an apology from you. Without any idea of your your level of knowledge and experience, old hands like him often have to respond with what may seem to be fairly basic replies, and often other readers will find the 411 useful, even though you are obviously knowledgeable in the meaning of your MIL codes.

Please fill out your signature line and keep in touch.

I’m beginning to notice a pattern here that more and more inquiries are going unanswered and I suspect many former regulars to the LB7 Forum have moved on.

Best
 

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Discussion Starter · #11 ·
The coolant hose that busted was the heater core connector that gets brittle. Not the first one to go. Last time the other side broke and it it filled the valley of the motor up, nothing happened to the truck. However the rubber plug on my FICM is missing. So there’s a hole on the casing. The wires are chafed going over that bracket by the alternator I separated and taped them up and still having these problems. Looking for a replacement ficm at the moment
 

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Discussion Starter · #12 ·
Going to keep updating in case this thread helps someone some day.
Came home from work. Fired up on two cranks. No check engine light but speedo is pegged out Pulled it out of the driveway and stomped it. GOBS of power. Roll past my brother in law in his PSD and give him the finger while dumping a big black cloud out the back. Truck is about to take flight it’s pulling so hard.....and then...... Dead pedal . Truck dies. Roll to a stop. Have to chain it to that 6.0 ford and have it pulled back to the house. Pop the hood and wiggle the frayed wires at the bracket. Starts again. Idles about 5 minutes and died.
 

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Towed home by a Ford !?!?!?

Oh, the humanity :(.

Sounds like the highly regarded “wiggle test” is getting you close to a solution!

And hey, easy with the black clouds! :).

While science says particulates fall out of the atmosphere fairly quickly, the image of belching diesels does none of us any good.

Yours truly, resident scold.
 
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