Stabilitrak/Traction Control Issues

If the dash light comes on, a trouble code is generated. If you don't see it with your scanner, my guess is that you are not using a quality bi-directional scanner, capable of identifying and displaying underlying control module or deep trouble codes.

I recommend that you get yourself a quality bi-directional scanner to add to your tool box. Then, you will be able to read ALL codes, along with a brief explanation/pointer to the source of your issue. You will literally save thousands of dollars in diagnostic and repair costs over the life of your truck, and you will most likely recoup the cost of the scanner within 1 year.

Joseph Garcia said:

If the dash light comes on, a trouble code is generated. If you don't see it with your scanner, my guess is that you are not using a quality bi-directional scanner, capable of identifying and displaying underlying control module or deep trouble codes.

I recommend that you get yourself a quality bi-directional scanner to add to your tool box. Then, you will be able to read ALL codes, along with a brief explanation/pointer to the source of your issue. You will literally save thousands of dollars in diagnostic and repair costs over the life of your truck, and you will most likely recoup the cost of the scanner within 1 year.

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Yup, my scanner has paid for itself many times over, not just with my Yukon, but with more than a dozen other vehicles.
I'm sort the family mechanic, so I have plugged into a lot of cars since I bought it.
My 2002 Nissan Altima had the chip key sensor in the ignition lock go out.
I bought a replacement sensor but the car was still stuck in 'locked' mode.
I thought I was going to have to have the dealer pull it out of Locked mode but I went ahead and reprogrammed all 3 keys to the vehicle for the heck of it and it worked great.
Saved me a tow and at least a $500 trip to the dealer.
That single use saved me more than the original purchase of the scanner.
The scanner has also been loaned out to friends that have scanned their cars for issues not able to be read with a basic scanner.

"Did you use a GM sensor?
Plenty of stuff I read online said only OEM sensors work correctly"

How true. I have found this an accurate statement on crankshaft and camshaft position sensors, oil pressure sensors, as well as the ABS sensors to name just a few of the more common ones. For example, stay away from Walker brand camshaft position sensors. It will not trip any codes, but it will only start on the second attempt.

rdezs said:

"Did you use a GM sensor?
Plenty of stuff I read online said only OEM sensors work correctly"

How true. I have found this an accurate statement on crankshaft and camshaft position sensors, oil pressure sensors, as well as the ABS sensors to name just a few of the more common ones. For example, stay away from Walker brand camshaft position sensors. It will not trip any codes, but it will only start on the second attempt.

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Some of the cam and crankshaft sensor issues like long crank times are due to the fact that a CASE relearn isn't done after one or both were changed. If it's not done, the crankshaft position sensor doesn't know where it is in relation to the camshaft, so if the ECM doesn't sense a start, it'll try with the opposite relationship. It might take a little time for it to switch, causing the long crank.

The engine can start without a cam signal, or with an unsynchronized signal, but long crank times may be experienced. Eric O describes how it works in this video:

The problem with mine wasn't a CASE relearn. For the first time in 30 years I let the dealer have it for a couple hours and try to diagnose. They were stumped. I had read something online, and told them to go ahead and change the camshaft sensor. And that cured the start issue. They were completely baffled. Even though the equipment showed the Walker brand camshaft sensor was sending a correct signal... It always failed on the first try. It created a bit of a stir at the dealership with the service manager. What it means is their own equipment cannot all the time determine if an aftermarket sensor is working properly or not. In the end they only charged me the minimum 1 hour labor charge plus the cost of the AC Delco camshaft position sensor.

rdezs said:

The problem with mine wasn't a CASE relearn. For the first time in 30 years I let the dealer have it for a couple hours and try to diagnose. They were stumped. I had read something online, and told them to go ahead and change the camshaft sensor. And that cured the start issue. They were completely baffled. Even though the equipment showed the Walker brand camshaft sensor was sending a correct signal... It always failed on the first try. It created a bit of a stir at the dealership with the service manager. What it means is their own equipment cannot all the time determine if an aftermarket sensor is working properly or not. In the end they only charged me the minimum 1 hour labor charge plus the cost of the AC Delco camshaft position sensor.

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Understood. But if a CASE relearn wasn't done when the Walker sensor was installed, the sensor may not have been at fault. The statement about only starting on the second attempt might mean the sensor itself was not functioning properly, or that the crankshaft position sensor had to apply the alternative attempt at starting.

They did the relearn twice with no effect prior to removing it. (And I had done it about a week earlier in the troubleshooting process) If I remember correctly, it was a review on Amazon or someone posted same experience that tipped me off.

Found it. "

Walker Products 235-1156 Engine Camshaft Position Sensor"​

Stay away from this item.

rdezs said:

They did the relearn twice with no effect prior to removing it. (And I had done it about a week earlier in the troubleshooting process) If I remember correctly, it was a review on Amazon or someone posted same experience that tipped me off.

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Ok, I didn't know that you had that done prior. Just a suggestion for future readers.

Just a good reason I suppose to always use AC Delco or genuine GM for the sensors. And based on what we discovered in my case, you can't effectively rule out an aftermarket sensor until it's replaced..... So going forward, if I buy a used vehicle, I guess I'll just have to go through and check all the sensors and make sure they are OEM. Like the guy at the dealership said, from what he learned you can't even begin any troubleshooting process without replacing any aftermarket sensors.