VEHICLES > DAILY DRIVERS/GROCERY GETTERS
GM Traverse StabiliTrak/Traction Control problem and PCV fix - update 10-22-20
goodfellow:
There are so many reported problems with this Traverse "StabiliTrak and Traction Control" issue across the net, that I've come to the conclusion that the main culprit is the throttle body (TB). That is to say, the TB gets contaminated by all the oil and oil vapor that condenses in the intake hose and then proceeds to gum up and compromise the TB stepper motor shaft over time. This is especially true in cold wet weather situations when the gummed up shaft tends to stick very easily due to small amounts of frost and ice forming on the TB; thereby making the stepper motor loose its ability to sense TB position.
The best way to keep these TB related StabiliTrak issues from occurring is to clean the TB regularly. I clean and inspect every 5000 miles when an oil change is due. If you take it to a dealer at oil change, they will not perform this TB service unless you specifically ask them to do it. Then again, this service will cost you a few $$$ extra at the dealer -- better to do it yourself and save the $100.
FIRST and most IMPORTANT -- REMOVE the IGNITION KEY from THE CAR and put it in your pocket. Do NOT leave the ignition in the "ON" position, or you can damage the TB stepper motor.
Next remove the vent inlet fitting from the intake hose (the hose that sits between the air filter housing and the TB) -- pinch the gray clips on each side and the fitting pops right off. Be careful, don't mess up the fitting or you'll get an air leak and an eventual trouble code will be set because this fitting is located after the Mass Air Flow (MAF) sensor.
Undo the hose clamps at each end of the intake tube (one at the TB itself, and the other immediately to the left to the MAF) and pull the tube free from the TB.
Take a can of TB cleaner and thoroughly clean the TB inside and out and wipe with a cloth rag to get all the dirt and grime. If you've never done this on your car and it has some miles on it, then you'll be surprised how dirty and "gummy" that TB is. Pay close attention to the two areas where the TB shaft enters the TB housing. It's these areas that get gunked up and make the TB stick. Use a straw on the TB cleaner can and spray these areas while moving the TB flap back and forth with your free hand. Follow up with a clean rag and repeat this process until no more gunk and grime leaches out from these areas -- done!
Next, take the intake tube and thoroughly clean out the oil trap that is molded into the tube. Spray brake or carb cleaner down the vent tube nipple and while using you other hand to hold a rag on the inside of tube to catch the crap that will be released. What you see has accumulated in only 5000 miles of driving -- people who have never done this before have literally a few ounces of oil accumulated in that well. Much of that oily residue stuff eventually winds up in the TB and screws things up royally.
It takes a good ten minutes to thoroughly clean that entire tube free of oil. Once that's done, replace and fasten the tube back on the TB and button up the two hose clamps. Also, securely replace the vent tube fitting on the vent tube nipple and everything should be good to go.
Now do the oil change if you're so inclined -- BTW GM now recommends a PF-63 AC Delco filter for this car because the original PF-48 was just a tad too small. The PF-63 is longer and thus provides more filter material to clean the oil. The car uses 6qts and it's VERY critical that it gets enough oil because in previous years the Traverse had serious oiling problems with the timing chain -- lots of expensive timing chain failures due to oil starvation.
BTW -- once all this cleaning is completed, the car will be hard to start and it will stutter and stumble until all that TB cleaner is evacuated from the intake manifold and sent through the combustion chamber. During this time the instrument panel will show all sorts of warning lights at start-up. This condition will only last for 20-30- seconds and will subside quickly -- no worries!
goodfellow:
This "traction control" problem hasn't returned in several years and the car is driving fine -- no throttle body problems at all. That said, this time around when I did an oil change, the oil trap in the intake tube was VERY dirty with oil; more-so than usual.
The problem obviously lies with the PCV system -- specifically the PCV valve gets clogged; which in turn increases crankcase pressures, and forces more oil vapors into the intake trap.
The solution is to replace the PCV valve (a $18 part at NAPA), or mod the current valve to be less restrictive and cure the problem once and for all. I chose to do the latter.
The PCV valve is located on top of the RR cylinder bank (the one closest to the firewall) -- right behind the throttle body. In fact once you disconnect the intake tube for cleaning, you can see the PCV valve close to the firewall. It has a hose attached that connects it to the top of the left cylinder bank. The hose connection to the left cylinder bank is difficult, so I only disconnected the PCV connection which has a simple push-in disconnect.
To get it out I used a body clip tool to catch the valve under the lip and lever it up and out
The valve has two breather holes on the bottom end and one of the two holes was clogged with carbon -- hence my oil vapor problem.
shining a light underneath it shows the restriction -- one hole is closed and the other one is partially open
The fix is to drill all the holes out with a 3/32" drill bit -- and then clean it out with lots of carb cleaner solvent.
Shining a light under the valve shows that this fix makes the passages much less restrictive -- and is considered a permanent fix.
Everything cleaned up and res-installed and this fix will go a long way to keep the oil out of the throttle body and prevent the dreaded traction control stall and power drop problem.
goodfellow:
Just an update on this PCV fix. It's made a wold of difference in keeping the throttle body and intake tube clear of oil vapor and oil condensate.
I changed the oil today and just look at the difference. The throttle body is clean and didn't even require any throttle body cleaner -- just a quick wipe with a rag and there was very little residue.
The oil trap in the intake tube was virtually spotless. Whereas in previous oil changes, after 5K miles the oil trap was filled with condensate and oily gunk, today the intake tube was almost pristine. This is what I cleaned out of the tube with a rag ...
.. inside the tube was virtually spotless.
Compare that to previous 5K oil change intervals, and the difference is stunning.
Bottom line -- to keep the dreaded StabiliTrak / Traction Control problem from reoccurring, the PCV fix is the permanent way to go.
stokester:
Great post!
While working at the local Chevy dealership I saw many Traverse vehicles with owners who did not ever check their oil level. This can be an issue for many things as the vehicles age and oil consumption increases. Low oil levels can lead to timing chain wear among other issues. Many of the customers had no idea of what the % of oil life meant.
Lesson learned for all vehicles is to check your oil regularly and change it with quality oil regularly regardless of the % of oil life remaining.
goodfellow:
--- Quote from: stokester on October 31, 2018, 05:46:15 PM ---Great post!
While working at the local Chevy dealership I saw many Traverse vehicles with owners who did not ever check their oil level. This can be an issue for many things as the vehicles age and oil consumption increases. Low oil levels can lead to timing chain wear among other issues. Many of the customers had no idea of what the % of oil life meant.
Lesson learned for all vehicles is to check your oil regularly and change it with quality oil regularly regardless of the % of oil life remaining.
--- End quote ---
Absolutely correct Nick! The Chevy 3.6 especially had problems with timing chains, and the company had to warranty many oil related issues due to oil interval monitors. I've followed this problem on many forums and at one time it was reported that on early GM Lambda platform vehicles the oil lubricating holes in the block were too small and starved the timing chains. That may well be correct, but in may cases the oil was never changed at regular intervals, and many folks used the cheapest Dino-based oil they could find. I'm a big fan of synthetic oils in modern tight tolerance engines -- and using the 5000 mile rule between oil changes (regardless of what oil it is) is money well spent.
When our Traverse oil monitor hits 25% it's clocked around 5K miles and time for an oil change.
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