Anybody familar with the relearn procedure needed after you replace the crankshaft position sensor on a 99 Malibu with quad 4 engine. I actaully have several questions about it. I know there is 1 procedure that involves using a scanner but I've actually seen another procedure that involves driving the car at certain speeds for certain intervals and wanted to know if anyone was actually familar with this procedure. Lastly and most important I guess does this procedure actually have to be done or are just certain instances that make this necessary. All help is needed as I'm having a very intermittent stalling issue with the car and wondered if this might be the reason why.

To do a case relearn, you would need a scanner to issue the command to the PCM so it can relearn it. Only a few high end scanners are capable of doing this including the GM Tech2.

Driving at certain speeds is what'* called the GM drive cycle. It involves driving at specific speeds and slowing down without using the brake. This tests the various monitoring devices on the engine and the fuel system. This test has nothing to do with the case relearn procedure.

If you have changed the crank sensor, some PCM'* will tell you via the check engine light if a case relearn is required.

So would it be safe to say that since the car starts and runs and there are no check engine or codes present the relearn does not need to be done?

Correct

I have replaced 2 crankshaft position sensors without case relearns.

I had mine replaced, and the mechanic did not do a relearn, so far so good.

If you happen to have an I-Phone, and 170.00 you could invest in Dash Boss, it has the ability to do case learns.

DashBoss Features

I have not gotten it yet, but plan to try it out on my 96 park Ave when I get the money.
It is not mentioned to work with any pre 2003 vehicles, but you can use this page to know how to check if you have the right pins for CAN.
DashBoss / DOWNLOADS AND UPDATES

Yea, those things are going to sell like hotcakes. NOT! Pretty soon, every single customer is going to want more options when it comes to bi-directional control. We have been bugging PalmerPerformance for a looong time to incorporate BD control in their software. We have even been bugging HPTuners to put ABS bleed in the software. They say its a liability. A liability!!!?!?!?!?! Whatever.

Did you have trouble (cold)starting it on days when it was really damp... after or during (heavy) rain, snowfall or just high-humidity... and it sat for awhile in said weather? If so, it'* ironic that this is occurring on another '99 GM product with a 6+1/7x crank-trigger driven DIS, as I have a '99 Sonoma w/LN2 (OHV 2.2L I-4) that has such an issue. I've also learned of a Cavalier & an *-truck--same model-year, same engine--with the same issue, so I doubt it'* really an uncommon problem. I guess GM unknowingly got a bad run of CKP'* for this DIS from their supplier, and the flaw really didn't rear it'* until some miles were on them.

https://www.gmforum.com/introduction...2015-a-304557/