Crankshaft Position Sensor

[elvin315]

Well, it finally happened to me. I have never been afraid to jump in my Cat and ripoff a 400 mile day. Now I'm not so confident. Last night I went out for a bite and she dies while backing out of the parking spot. When I started her in the garage she stalled. I thought I just hadn't kept the starter on long enough. The engine caught quickly the second time and off we went. There were a few stops before the diner and she started fine each time.

When she did die there was no CEL but the Sport light (s inside a cog) was flashing. I have a ScanGauge installed and immediately checked for codes. There were none. Still, from hanging out here and learning, I'm sure it was the CPS. The engine would crank strongly. I replaced the battery 2 months ago for an unrelated reason so I'm sure it wasn't that. I pushed the car back into the spot and checked under the hood for anything obvious. Not knowing which cable was the CPS I wiggled as many as I could. After 15 minutes I tried again and she fired right up. The Sport light was still flashing.

Not wanting to tempt fate and try a restart I headed for home. The transmission was in limp-home mode and engaged only 3rd & 4th gears. Highway performance was normal. Once back in my garage I shut her off and restarted. The engine started fine with no flashing Sport light. I took a lap around the neighborhood and everything was back to normal.

I haven't replaced it yet. I want to shop around for the part first. When I get it I'll have my local mechanic change it. I know it's an easy job but it's too cold for me to lay on an unheated garage's floor. I'm due for a car inspection and oil change. The sensor mounts next to the oil filter so while the car is up on the lift he can change it easily.

I hope my snap diagnosis is correct. I'll be renewing my AAA membership just in case.

Elvin

PS: One more thing. As I checked old posts for CPS info I found a reference to the Fuel Cap Alarm being related to the CPS. I have been seeing the FCA intermittently for at least 6 months. I can't say for sure but if you get the Fuel Cap Alarm it could be a warning sign of a future CPS failure.

[CateraMV6]

That is some quality info here, I am glad you didnt get stuck somewhere in the middle of the roads...
How many miles does your car have, maybe mine will be due for one of those soon, no signs of anything yet but who knows it might happen soon, I jsut turned 90K.

Check around the dealers for prices, and then find a GM website that has a lower price and they usually price match no matter what...
My Idler arm went from $147 to $97 so not bad I guess...

[Cadi Cat]

Originally Posted by elvin315

Well, it finally happened to me. I have never been afraid to jump in my Cat and ripoff a 400 mile day. Now I'm not so confident. Last night I went out for a bite and she dies while backing out of the parking spot. When I started her in the garage she stalled. I thought I just hadn't kept the starter on long enough. The engine caught quickly the second time and off we went. There were a few stops before the diner and she started fine each time.

When she did die there was no CEL but the Sport light (s inside a cog) was flashing. I have a ScanGauge installed and immediately checked for codes. There were none. Still, from hanging out here and learning, I'm sure it was the CPS. The engine would crank strongly. I replaced the battery 2 months ago for an unrelated reason so I'm sure it wasn't that. I pushed the car back into the spot and checked under the hood for anything obvious. Not knowing which cable was the CPS I wiggled as many as I could. After 15 minutes I tried again and she fired right up. The Sport light was still flashing.

Not wanting to tempt fate and try a restart I headed for home. The transmission was in limp-home mode and engaged only 3rd & 4th gears. Highway performance was normal. Once back in my garage I shut her off and restarted. The engine started fine with no flashing Sport light. I took a lap around the neighborhood and everything was back to normal.

I haven't replaced it yet. I want to shop around for the part first. When I get it I'll have my local mechanic change it. I know it's an easy job but it's too cold for me to lay on an unheated garage's floor. I'm due for a car inspection and oil change. The sensor mounts next to the oil filter so while the car is up on the lift he can change it easily.

I hope my snap diagnosis is correct. I'll be renewing my AAA membership just in case.

Elvin

PS: One more thing. As I checked old posts for CPS info I found a reference to the Fuel Cap Alarm being related to the CPS. I have been seeing the FCA intermittently for at least 6 months. I can't say for sure but if you get the Fuel Cap Alarm it could be a warning sign of a future CPS failure.

ah ha, so that's what that was....! the fuel cap alarm that is. I thought it was just not making contact at times. My car had the exact same symptoms. It never drew my attention after I changed the cps. And now that you bring it up I have never gotten that warning since. So yeah maybe an early warning failure???

[elvin315]

Originally Posted by Cadi Cat

ah ha, so that's what that was....! the fuel cap alarm that is. I thought it was just not making contact at times. My car had the exact same symptoms. It never drew my attention after I changed the cps. And now that you bring it up I have never gotten that warning since. So yeah maybe an early warning failure???

Thanks for verifying that. I found that info way back in the archive but since I'd never read it before I was doubtful. That Fuel Cap Alarm can be useful I guess. I ordered a new Crankshaft Position Sensor yesterday from GM Parts Cheap for $34.99 plus $9.95 shipping.

Elvin

[elvin315]

I wanted to put an ending to this story. I just finished an 900 mile weekend with my new Crankshaft Position Sensor and the engine never skipped a beat. It started every time. No stalling. No codes. Nothing. Thanks to the information here I was able to save myself the frustration of dealing with clueless service techs. I ordered the part, handed it to the service manager, they installed it, and that was that. I was a little nervous during the first 30 miles of test drives before the weekend trip but after that I stopped staring at the gauges. Except for the speeding ticket I got (81 in a 65 zone) it was an uneventful trip.

Elvin

[elvin315]

Originally Posted by CateraMV6

How many miles does your car have, maybe mine will be due for one of those soon, no signs of anything yet but who knows it might happen soon, I jsut turned 90K.

It just turned 68,000 miles this weekend. After rooting around the engine and tracing the CPS cable I don't think the sensor actually wears out. It's the cable itself that's the problem. It passes very close to the left hand exhaust pipe. I think the heat damages the sheathing (either melts it or cracks it) and shorts the sensor leads. I forgot to ask for the old part so I don't know which. Even though the cable has heat shielding, the farther away from the exhaust the better.

Elvin

[usc2005]

Originally Posted by elvin315

Thanks for verifying that. I found that info way back in the archive but since I'd never read it before I was doubtful. That Fuel Cap Alarm can be useful I guess. I ordered a new Crankshaft Position Sensor yesterday from GM Parts Cheap for $34.99 plus $9.95 shipping.

Elvin

Elvin, you guys mention fuel cap alarm. Does something go on with that that lets you know of a future csp failure. Can you go into detail? i just turned on 60000 miles and was wondering if i should change it now to prevent any harm?

[elvin315]

Originally Posted by usc2005

Elvin, you guys mention fuel cap alarm. Does something go on with that that lets you know of a future csp failure. Can you go into detail? i just turned on 60000 miles and was wondering if i should change it now to prevent any harm?

Nothing definitive but with all the electronic sensors and monitors who knows how the ETBCM interprets the signals. It could mistake an intermittent CPS alarm for a Fuel Cap Alarm. Vesicant's reply in the following thread is what caused me to wonder.

http://www.cadillacforums.com/forums...ing-light.html (99 Catera "Fuel Cap" warning light comes on)

Elvin

[Cadi Cat]

when I installed my cps I routed it as far away as I could from the exhaust. We'll see what happens with that. It died at about 100k. 140k on it now no problems since. :knock on wood:

[elvin315]

Originally Posted by Cadi Cat

when I installed my cps I routed it as far away as I could from the exhaust. We'll see what happens with that. It died at about 100k. 140k on it now no problems since. :knock on wood:

I forgot to mention that the cable should be kept off the oil lines too.

Elvin

[Boris]

Might be a dumb question but when the crank sensor dies and you crank the car does the fuel pump shut down as well ?