Hey Guys, Getting a lot of errors 2010 Buick Lacrosse 3.0 CXL, V6.

Evap Leak: Already Changed Gas Cap And Purge Valve - Found Small Hole In Hose Next To Purge Valve And Sealed It. Still having error codes..

U-0140-71 Error Seems To Be Communication With BCM, Throwing A Bunch Of Codes. Checked Wiring, Fuses Everything Seems Intact And Fuses Are Good. Don't Know WTF??

(Also not experiencing any problems the BCM that would throw out, like power windows, door locks, etc. And no idiot lights on dash except check engine for Purge Leak & tire monitoring light due to bad batteries in tire sensors)

Just Spent Over A Grand$$ Replacing ECM At Dealer Last Month Because They Are Only Ones Licensed To "Program" Computer.

Trying To Avoid Another Grand At The Dealer. If You Have Any Suggestions Appreciate it.

Thanks.

How any miles on this car?

How many miles have you owned it?

Has it been through any major trauma such as floods, accidents, poor repairs, etc.?

What was wrong with the ECM?

Have there been any repairs done on this car recently?

What region does this car live in?

Has it lived in any other regions?

I see two codes:
- P0455 - Major EVAP leak
- U0140-71 - Communication loss with BCM

What other codes are there?

What lights are on on the dash?

Miles 81K - Hand-me-down family car- No Accidents/Floods - Southeast - ECM was replaced because "limp mode" slowing vehicle down
You are correct those are the codes that show up. Car runs fine, except check engine light, Only scanner picking up other codes.

If you clear the codes do all the same codes consistently return? And how quickly do the codes re-appear?

So no loss of communication with the BCM before changing out the ECM?

Possibly, thought the new computer ecm would fix those issues.

I've cleared codes before engine light goes off then within a day or two comes back on. Can't find source of vacuum leak, changed purge valve and gas cap, same codes.

Even the loss of comms to the BCM returns?

A month ago it was "key ignition" loss comm. Now that'* gone and "anti-brake system" loss comm nut runs fine. Of course if I bring it to dealer they'll just throw in new one and hope for the best. should be a better way to diagnose.

There is. They aren't doing it. My opinion: Dealerships aren't good at diagnosing, especially on anything that'* not under warranty. Take it to a reputable independent shop.