: 05' STS engine shut off while driving!

06-26-12, 12:37 AM
This has now happened to me twice over the last few months. Both times it has been from a cold start within the first 5min of driving at a low speed. While driving about 25mph, the engine just shuts off and of course I loose my power brakes and steering. The first time I pulled over, put it in park and it started right up. The second time (today) I was on a busy street so I shifted into neutral, re-started, then back into drive.

Otherwise runs perfect. No code. No rough idle. Plenty of power. It did say check engine oil level, but not sure if it said that because the engine wasn't running?! I checked anyway and it was low, but could be seen on the dipstick.

I'm just shy of 100K mi. I saw this was an issue on older STS models with the crankshaft sensor. Any ideas?

06-26-12, 02:29 AM
Failing CKP sensors should throw a code, but there are cases where they won't if they're just beginning to fail.

06-26-12, 04:36 AM
perhaps a faulty start button? could it have thought you turned off the car?

06-26-12, 09:25 AM
Could also be a fuel pump going bad.

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06-26-12, 03:35 PM
Thanks for the input... I just dread taking it to the dealer! :bigroll:

06-28-12, 01:31 PM
You don't indicate if yours is a Northstar engine. I had this problem with an older Seville and it was the crankcase position sensors failing. In my case, the car would stop only at idle as stopped for a stop sign. It would always restart and didn't fail except at idle; and then, only occasionally. I had the sensors replaced and no more trouble. I don't remember seeing any service engine codes; however.

06-29-12, 03:20 AM
I don't remember seeing any service engine codes; however.Two different things.

Service engine soon light.

Diagnostic trouble codes (DTCs)

In almost all cases, a failing crankshaft position sensor will set a code, but that will not trigger the service engine light.

06-29-12, 07:48 PM
Low oil is a serious problem. If you saw an oil light or warning, a 3.6 may already be toast. The Northstar is tougher.

06-29-12, 09:32 PM
Thanks for the input... I just dread taking it to the dealer! :bigroll:

Had a 92 bonneville that displayed the exact same symptoms. My mechanic had it for a week and half. I don't remember exactly what the story was but his advise was I needed a new car. Took it to the dealer. Called me up the same day, told me it was the flywheel sensor (or crankshaft sensor), said they needed a day to get the part and it would be ready the following day. Drove the car for another 75k miles. I've been a fan of my dealership ever since. They ain't cheap, but they're available when I need them and they get the work done in a timely manner. And when I need one, they give me a loaner.

I did the local mechanic thing for years and had mostly good service and can't say I'll never do it again. Until my dealership gives me a reason to go elsewhere, they'll continue to get my business.

06-29-12, 09:55 PM
This is in response to MoistCabbage...
I know the difference between a check engine light and the service codes on a Seville. When my 98 SLS was experiencing this problem, it did not set a service/check engine light! Nor was there any service codes when I viewed the data on the DIC (Driver Information Center). Irrespective of this, the repair was to replace the crankshaft position sensors. I know this was the correct repair because I had (still have) the original GM shop manuals for that 98 Seville SLS.

Now, related to the actual repair, and a reason you need to find a competent dealer; when I came to pick iup the car after the repair, I was stunned at the amount of labor charged. When I questioned the amount, the guy behind the counter said, "Well, you know we have to pull the engine to replace the these sensors."

I replied, "No you don't. They can be replaced through the wheel well. It's not a difficult job."

The guy behind the counter asked, "How do you know that?"

When I replied "I have the GM shop manuals for this car", he excused himself and when he returned he had reduced the labor charge from 4 hours to 1.5 hours.

GM pulled their franchise about a year later!

07-03-12, 01:50 AM
Low oil is a serious problem. If you saw an oil light or warning, a 3.6 may already be toast. The Northstar is tougher.

I do have the N* btw. I park on a really steep driveway and my warnings always say, "check coolent level", "check washer level", "check oil level", and every time I do they are fine. Since the engine shut-off I have been parking on the street (very level) just so I can see if it makes a difference. Like I said in my origianl post, when I checked the oil level it was still showing on the dipstick, just about a 1/2qt low.

Well, car is under warranty and I have a few things now that need to be fixed, so I guess I'll just have to take it in. I just wanted some input in case they try to deny a warranty claim.