Armada/QX56 4WD/SLIP/VDC/ABS self-test

[amfoyle]

I'm trying the self-test from the FSM for the 4WD/SLIP/VDC Off/ABS warning-lamp combination, but there's no diagnostic flashing to frequency-time upon test completion. I've tried it a few times on a 2008 Armada since the lights popped on last week.
Any ideas on why? Or what I'm missing? I'd like to narrow down the possible causes. Thanks!

[centralcoaster33]

Hi and welcome to NICO Club!

SRC chapter right? Starting at Page 13 to get to 'user mode', then later on Page 15 procedure 6 to get to diagnoses mode, then page 85? It says if no error in user mode, then no option to get into diagnoses mode. What step are you hung on?

Here's what I'm lookin' at: http://www.nicoclub.com/service-manual? ... Armada/src

[amfoyle]

Thanks!
I'm at DLN p13, p17 particularly, and p97-98 for flash codes, to find the causes of this 4-light combo light-up.
It's not an SRS issue.
I don't get any flashing pattern (p97-98) that would indicate where the problem is.

[amfoyle]

Well, it was a left rear wheel bearing going bad - at 80K miles. Warning lights now off, and the truck has much low-freq hum/wum-wum/drone at 70mph.
The bearing is stiff to turn when in your hand, but I don't know how easily one of these bearings should spin when off the truck - will a quick flick of the wrist set it spinning for a few seconds? Or will it just (grudgingly) turn and not free-spin at all?

[centralcoaster33]

A good sealed bearing won't make any noise, won't have any play, will turn very smooth and easily with force and will not spin freely without force because of the lubrication. An obviously bad bearing can be stiff, spin for days (because it's dry), mishapen, or feel clunky or like grinding when rotating. Bearings can go bad and be less than obvious when inspecting just the bearing alone.

[amfoyle]

Thanks. It was an indie mechanic diagnosis and a $410 repair. The bearing has no noticeable play, rotates with what I think is much force, feels slightly gravelly/gritty, and occasionally gets lightly stuck on part of a rotation. It's definitely subtle, so trusting the mechanic on this one. Will attempt the right-rear one myself within the year as mechanic mentioned it may need to be replaced within the year. ABS sensor looked fine and still grease covered. I could just wait until the ABS light comes on next, before doing that other-side repair!