Buick Repair Questions? Ask a Mechanic for Answers ASAP
Sorry you have had to wait so long.
Do you have a voltmeter or 12 volt test light in order to complete a few electrical tests?
If so, can you tell me if fuse #48/ ign switch has voltage? This fuse is in the rear fuse block, below the left rear seat. This fuse should be hot even with the key off.
If yes, then tell me if the fuse ecm ign 3 in the underhood fuse block has power with the key on run and start. This fuse block is forward of right front strut.
The "crank" fuse should also be hot even with the key off. This fuse is in that same fuse block underhood.
Also an "ecm crank fuse must be hot when the key is on start. same underhood fuse box.
Before I forget, here is the wiring diagram,
Remove the crank relay, test the prongs in the socket for voltage. One should be hot with the key off, turn the key to start and let me know if an additional prong in that socket now is hot.
That is the crank relay 3.
I don't know which is terminal 85, does 2 have voltage when the key is on start? If so, have you replaced that relay yet?
You know what, even before that. Let's check that other relay, too.
Even before that, put your finger on that crank relay 3 and feel if it clicks when the key is turned to start.
If it clicks, replace that relay. If it doesn't click, let's go and test that other crank relay, the run/crank relay 6.
Actually you already confirmed that "ecm ign 3" fuse had voltage with the key on start, didn't you?
Then the problem could be with the signal from the park/neutral range switch at the transmission to the pcm.
Do you have a scan tool?
Make sure these grounds are tight, especially that G112.
That g112 is the ground for the park/neutral range switch as well as the maf, iat, ecm, eop, and both of those crank relays 3 and 6.
I would suspect that g112 ground since you were having so many electrical outages, then work back from there or if it's ok, just go back to those other checks.
Were there any codes? Does your scan tool retrieve codes from more than just the pcm?
was g112 tight?
I gave you a diagram showing you where it was, Bottom Left Side Of Engine.
That is for the vin 2, 3.8l engine. Maybe you are confused about when they said Bottom Left Side Of Engine. That would be the drivers side I believe.
I am sorry, but that is what the Mitchel manual has for that. If they are wrong, don't blame me.
go back to where I said "I don't know which is terminal 85, does 2 have voltage when the key is on start? If so, have you replaced that relay yet?" and start there.
That isn't the way I wanted to test.
If you want to do things that way, I won't be able to help.
If you want to actually do some testing, I can help.
You have a scan tool. What were the other 2 codes? You said lost communication with the engine. That isn't a valid code.
I'll be able to walk you through the process to get your car running but you'll need a voltage meter a test light and a few small tools. Please accept the live phone call reguest to expedite the diagnostics. Thanks