2005 Saab 9-5 ARC 2.3T - Stall and Trouble Starting

Maintenance/Repairs
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1

Hello everyone, I apologize for the length but I figure it is better to explain the issue

2005 Saab 9-5 ARC 2.3T
67,000 Miles

Noticed a problem 2 weeks ago with my little Swedish meatball while at a red light on the way home. While idling, the car just shut off. I’m assuming it was a stall, but the car did not sputter and it was idling at around 900-1k RPMs but then just cut out. I put the car in park, and it started right up without issue and I drove the rest of the way home with it running fine. A couple days later, the same exact thing happened.

I took it in to my local Saab shop for a radiator hose replacement and an oil change. I told him about the stall/cut out problem, so he hooked up the Tech II but could not find any trouble codes. So he did a software update to the computer and told me to monitor it and call him if it happens again.

After getting my car back, it ran fine for a few days. I tried to get it to stall again by just letting it run in idle for 10-15 minutes but it wouldn’t cut out. One night, I went to the gym for about an hour and came out and my car started right up and I drove about 5 minutes and came to a light. Car cut out again. However this time, it did not start up again. The engine would crank, the computer would go through the checks and give me the Check OK but it just wouldn’t turn over. I tried to start it 5 or 6 times but no luck. I got out and pushed it to the side of the road. After about 2 minutes for sitting there, I tried it again and it turned over. Started right up like nothing ever happened.

The car drove again fine for a few days and then yesterday it cut out again. Same thing. Car would crank but not turn over. I let it sit there for 2 minutes (as traffic was going around me at a red light :confused: ) and then tried it again. The engine turned over but it did not start up fine. It definitely stuttered as it was trying to start and I had to give it some gas to get it running smoothly.

Couple of observations:
This has only happened while idling (in Park or Drive)
This has only happened when the car was warm. I’ve never had an issue starting in the morning or before the car warms up
This appears to only occur when it has been warm outside. (We’ve had a few days in the 60s here in PA)
The Check Engine Light has never come on. So no trouble codes have ever been logged.

I’ve been searching the forums and most people seem to recommend replacing the Crank Position Sensor (my mechanic wants to do this as well). However from what I understand, if it was the CPS the car wouldn’t stutter like it did when starting after a stall and wouldn’t the CPS cut off the engine while driving as well?

Any advice? Is my mechanic right or this something to do with the throttle body?

regards,

John

2

Just because the check engine light isn’t on doesn’t mean there’s no trouble codes STORED.
The crankshaft position sensor is actually called a CKP sensor, by the way.
I’m a little confused by your use of the words turning over and cranking. They’re supposed to describe the same thing. To say an engine won’t turn over/crank means that it physically won’t turn (possible seized engine).
Bad CKP sensors can cause the engine to simply shut off.
Have you checked fuel pressure and spark?
At least you’ve got the latest software . . .

3

When you have a no-start condition have you tried depressing the accelerator pedal to see if the engine will start then? If not, try this and see what happens.

If the engine starts then I would suspect a problem with the Idle Air Control valve. These can be problematic on any car and may not set any codes at all.

Sometimes cleaning the valve and IAC passages can help solve this problem. Your car has comparatively low miles for the age and if the bulk of your driving is city, short hop stuff then that kind of driving is conducive to creating IAC problems. Think of chimney soot. :slight_smile:

4

Just had the same issue with my 2001 Saab 9-5 2.3T (148k miles on it). Long story short, it was the crankshaft position sensor, but it took three mechanics to figure it out.

Just as described by ShamrockRover, engine was shutting off when I slowed down, or stopped at a light. Battery is fine, and engine was cranking/turning over, but the engine just wouldn’t start. Tried pressing the accelerator pedal while starting but that didn’t help either. Thought it probably wasn’t the Idle Air Control (IAC), because the car would idle fine, no engine hesitation or anything…it would just shut off after a bit of driving and then not start again for at least 30 minutes.

First Mechanic said it could be a bunch of things and I should take it somewhere else. The second mechanic (muffler guy because I also had an exhaust issue) checked sensors in the throttle body and said none were malfunctioning. He said he found some oil buildup in the throttle body and thought that it might be the positive crankcase ventilation (PCV) valve, so he replaced it and cleaned out the buildup. I even told him to check the crankshaft position sensor (CKP) and he didn’t seem to think anything was wrong with it. So, I picked up the car and drove it home, but it happened again.

I took it to a GM mechanic. They said the car was running fine and they didn’t see any problem with it. I told them to go drive it for about 20 minutes and it would happen. He called me back and said that the car did shut down on him after a short drive. He said flat out it was the CKP and made the repair. Been driving for 2 weeks now and it is all fixed.