Rough Idle, Service Stabilitrak, Service TC, PO 122 PO 223

Patrick Afams · October 1

Was trying to find the thread that started talking about this issue, couldn’t find it. I’ve fixed the issue with spontaneous “stabilitrak, tc PO 122, 223 and rough idle”

The throttle body needs to be replaced. Buy an OE Dorman or genuine replacement part or it will be a pain to fix, the relearn procedure WILL take longer than it should with rebuilds and Hitatchi units.

The reason the throttle body is the issue is simple; traction control and stabilitrak both need to make use of the electronically controlled throttle body to work. When TC is on and your rear tires start to spin, it shuts the butterfly valve to lower RPM’s so your tires stop spinning. The rough idle is thanks to the butterfly valve opening intermittently or poorly.

The PO codes I think are from a bad capacitor or something inside the bad throttle body. Maybe it ruptures or there’s corrosion on a resistor that overloads/starves the electrical system and causes it to malfunction. Can the original broken unit be rebuilt? Maybe, but I wouldn’t trust a shop unless they really know their way around GMT900’s.

Most idle issues stem from the throttle body, not MAF or temp sensors. My dad and I both have matching 2011 tahoes. He’s been on his 3rd throttle body for a couple months, I’m on my 3rd now.

After replacing the unit, the PO codes still showed but the truck drove perfect so I guess they were still there from before? Not entirely sure.

While you have the throttle body off, it’s also a good time to pull the intake and clean it as best you can. I’m at 207k miles and I had a LOT of carbon buildup.