1998 Oldsmobile Aurora crank sensor replacement

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wildman

1998 Oldsmobile Aurora crank sensor replacement

Unread post by wildman » Tue Aug 03, 2010 9:55 pm

I have the 98 Aurora with the 4.0l v8 and the check engine light is intermittently coming on- and sometimes it's hard to start. I had the codes read, and was told the crank sensor and ecm both failed.
First question is, where is the sensor on the 4.0? I have been told to remove the starter, the oil filter adapter, and the power steering pump to look for it- but ravaging the motor to explore seems a little extreme to me.
Second question is, could/would the crank sensor cause an ecm reading without the ecm being bad? The car gets great gas mileage and runs great (even when the check engine light is blaring) .
Any insight will be appreciated,, thanks

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butchkaz
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Re: 1998 Aurora crank sensor

Unread post by butchkaz » Tue Aug 03, 2010 11:38 pm

The 4.0 L v8 has 2 crank sensors.
They are pretty common to fail, but not the ECM so much.
They are located on the front of the engine. Accessed from under the car. Above the oil pressure sender and near an A/C line. 10mm bolts hold each onto the engine.
One is a little higher up from the other. You can bend the A/C line a little to get enough room to pull the lower one all the way out. Very stiff, but it will move enough.
Then the upper one comes out easier as well. Removal of the oil ressure sender will also help. Actually, have broken a few oil units getting the crank sensors out, so may just want to remove it first. Use a 10mm swivel on a short extension to get the bolts for each sensor.
After replacement, you may need to do a "Crank sensor correlation relearn" with a scan tool, or a crank sensor code may return. This is basically a calibration.
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wildman
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Re: 1998 Aurora crank sensor

Unread post by wildman » Tue Aug 03, 2010 11:49 pm

Thank you so much- if I can get my hands on the parts tomorrow it'll be fixed. You mentioned that it might need programmed, do the regular scan tools you buy at the parts counter have this ability, or is it a more extensive procedure? I have been window shopping for a reader for some time now, but have been leaning a little more towards the usb pc based route a little more.

Thanks again-- I have been scouring the web for this information- thanks
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butchkaz
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Re: 1998 Aurora crank sensor

Unread post by butchkaz » Wed Aug 04, 2010 12:02 am

wildman wrote:Thank you so much- if I can get my hands on the parts tomorrow it'll be fixed. You mentioned that it might need programmed, do the regular scan tools you buy at the parts counter have this ability, or is it a more extensive procedure? I have been window shopping for a reader for some time now, but have been leaning a little more towards the usb pc based route a little more.

Thanks again-- I have been scouring the web for this information- thanks
A simple code scanner will not be able to do this.
It needs a little more advanced tool, since this is a learning procedure. Most PC based will have the ability to do this, as well as being able to control different systems for testing procedures- like cycling EVAP system solenoids, cycling injectors on/off, compressor relay control, ETC.
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wildman
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Re: 1998 Aurora crank sensor

Unread post by wildman » Thu Aug 05, 2010 10:00 am

Thanks for all the help. They were exactly where you described and easy to find after I knew where to point. Both are changed, I removed the oil sending, then used a wrench to take them out. Turns out changing them was needed because there was oil leaking from around the lower. Or perhaps they were changed and just not calibrated, either way I shouldn't have to worry about them for some time now.
Next will be buying the usb reader and turning the check engine light off for good- but that will wait for pay-day lol
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Re: 1998 Aurora crank sensor

Unread post by butchkaz » Thu Aug 05, 2010 12:28 pm

Glad we could help.
Come visit again !
Maybe you have something to add to some other posts...
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