I have a 2008 Lucerne CXL 3.8 V-6. Three weeks ago I pulled up to a stoplight and the vehicle stalled. I restarted it and it began to run very rough and then shut off. I attempted to restart but the engine would only crank and not start. The vehicle had stalled 3 or 4 times over the past four months. When the previous stalls occurred the vehicle was completely dead (no crank no start). I would wait less then 5 minutes and it would start back up and run perfectly. Long story short I had it towed after the last incident and that’s where the adventure begins. 1st mechanic attempted to replace the crank sensor and ICM (used) (programmed with my vin number) to no avail. He tinkered , poked and prodded with the ignition system but still no ignition. The car was then sent to a GM Garage. They advised that because the crank sensor was aftermarket and the ICM was used that it was probably not talking to each other. So new ICM (genuine GM part) was purchased for $466.00 and GM Crank Sensor and pigtail for another $300.00. This has been 10 days now and I still don’t have my car. My question(s) is what else could be causing this issue? As it stands now they are just throwing parts at this problem and still no repair… HELP PLEASE

 

When you say , NO crank, No start
Neither ICM nor crank sensor will cause this.
Either you are not providing complete info or we are not understanding exactly what is happening.

When you attempt to start the engine it has to crank over then start. Did it do anything when you attempted to restart it?

If there is a poor connection right at the battery, the charging system doesn't know this , all it knows is it is receiving resistance and so must lower the charging rate.
That resistance could be corrosion at the battery terminals which can cause the engine to quit running and refuse addl charging.
Electrical connections can be unpredictable at times and nothing can be taken for granted.
Before offering anything, would like to be sure the symptoms you state are accurate.
Can you help me out here?

As far as you know, does it seem to be heat related ?

 

The no crank / no start has happened 3 or 4 times in the past couple months. The motor would just die and when I attempted to restart everything was dead. I would wait 5 minutes or so and attempt to start and everything would fire up. No warning lights came on, it would just start up like normal and run smoothly. The last time it happened the car started to die and was running very rough and eventually stopped. When I went to restart the motor would just crank and not start. Had it tower to a local mechanic and he worked on it for over a week and said he could not get it to start. He put in the reconditioned ICM and Crank Sensor to see if it would help but it didn’t. He then sent my car to a GM Service Center and they said it probably needed a new OEM ICM (not reconditioned) and a OEM Crank Sensor. They have had the car going on 2 weeks with no headway being made. I’m a bit frustrated before I really love this car.

 

As another item to check is the rear fuse box and especially the fuel pump fuse and relay for burnt areas or melted plastic in the box. There is a GM TSB and a YouTube video on this but it can be overlooked and from the posted information sounds similar to some of the issues caused by it.

 

 

It has been posted on other sites, but the issues vary on what the problem and repair on the individual vehicles as it's not necessarily one size fits all. The list can be the rear fuse box again, battery, bad harness, PCM etc. Not knowing what the service history on the vehicle or it's past problems it's somewhat best guessing over a forum. If the GM shop worked on the vehicle, installed replacement parts and returned your vehicle in worse condition than it may be worth getting them to at least get to where it was.

 

Thanks to everyone who posted on my thread and gave me information. My 2008 Lucerne is repaired and running great. It’s been a journey but it was educational from a Buick owner standpoint. It turned out that when they (mechanics) were working on my car they blew a ignition fuse. When they replaced it they were able to crank the motor and found that a couple of the ignition coils were bad and another issue with a wiring harness. No I didn’t need a crank sensor or an ICM. Like I said thanks for your input… I passed everything you all advised onto the GM Service Center mechanics.

 

Isn't that great? Have a nice day