Engine Crunching with VSA Activation, then VSA, SHAWD, AFS lights all on
 

To begin, I even checked the thread about the threads to see if I could find this exact issue.

I have a 2009 RL and just recently I’ve run into a recurring problem: either all three of the VSA, SHAWD, and AFS lights come on within seconds of startup, or I begin to accelerate (slowly, straight, on dry ground) and I hear a crunching sound coming from what sounds like my engine bay, while my VSA triangle flashes, and my car subtly jolts around, followed by *ding* “Check VSA System” *ding* “Check SH-AWD System” *ding* “Check AFS System”

The problem does not occur if I disable VSA on startup, but eventually SHAWD and AFS lights come on around 5th gear/overdrive shift. However, before I get to that shift, I have noticed in the SHAWD section of the dash display (that shows the amount of power going to all 4 wheels marked by little squares) that my back left wheel is receiving little to no power at all times, regardless of turning or level of acceleration. Then once the warning lights have come on, of course the failsafe of only powering the front two wheels comes on, and I’m back to driving normally, but with no VSA or SH-AWD or power to my rear wheels.

My battery is only two years old and puts out plenty of power (had it tested).
I have an aftermarket subwoofer and amplifier installed, but the issue arose before that.
I am thinking of replacing rear diff fluid because Jiffy Lube doesn’t replace that with their oil change like they do other fluids.

Any ideas?

The 'engine crunching' part seems odd.
The one wheel not getting power is odd.

You did not mention recent work, or previous issues that may be related.Or did any of these lights previously come on by themselves, with no other lights on...

How long since you changed differential fluids front and rear? trans fluids?

I know SHAWD usually follows VSA. If VSA goes on, shortly later you'll get SHAWD.

You need to be more specific as to the crunching noise, and if its from engine really or from the transmission or drive area (all wheel drive).

Also, if the battery is a dealer battery, 2 years is it's life; most need replacement shortly after 2 years of life.

Also, have the codes been cleared at some point by anyone. Or for any other reason have all the codes and settings deleted from the computer?

If so, and you lost your 'Neutral Position Memorization' setting, VSA will not work. I think AFS too since the car doesn't know how to set that leveling sensor. And SHAWD will light up if VSA is on.

A code scanner compatible with honda/acura should help set neutral position memorization. It's what you need to do before any other light.

If you have no scanner, you can try this, but follow every step carefully don't mess it up:

Check battery terminals

Thanks for all the tips!
-The sound seems like it’s coming from deep under the engine; feels almost like VSA is activating to try to maintain traction even though I’m going slow and straight, so most likely drive area.
-Battery was replaced with interstate battery two years ago and terminals look secured properly. I am, however, running power from the same battery through a separate cable/fuse to my subwoofer/amp in the trunk.
-I don’t recall recently changing the transmission fluids or front/rear differential fluids unless Jiffy Lube routinely does it with full service oil changes, but would that cause the back left wheel to not receive power and/or cause the Check Active Front-lighting System (AFS) to come on?
-I’ll see if I can find somebody with a code scanner to set neutral position memorization. I did recently have Tire Discounters wipe my codes, but not all my settings. Probably won’t risk the YouTube tutorial out of fear of messing it up.
-I had my alignment done by Firestone along with a Steering Angle Sensor reset, if that’s what you’re referring to by neutral position memorization

Have you lost your manual and service paperwork ? These various fluids are service items and should be replaced on a scheduled basis - the exact schedule is listed in your service history book. If the only servicing you're doing is at Jiffy Lube, you'll be missing a whole bunch of things - I think it's very unlikely they'll be changing anything but the engine oil.

I have the service paperwork and just read that the last rear diff/trans/front diff fluid change was 60k miles ago 🤦🏼♂️
should I go to my Acura dealer for diagnostic since it’s been so long? Or should I start by replacing all the fluids and resetting neutral position (which I fully understand how to, thanks to other forums)?

Well the AFS sensor is right behind the rear left wheel. Maybe your problem is indeed electrical.

Firestone did your steering angle sensor? That damned sensor when not done right can have all sorts of lights go nuts, and the car drives very funny. The dealer had to re-do it for all to be well.

I'd start by having those done i guess... steering angle sensor and neutral position memorization. It's shouldn't take a dealer more than 30 mins to do them.

The car's computer is supposed to tell you when to do each service interval. Is it not telling you?

That’s really interesting that it seems to be a left-wheel-centric electrical issue.
Yeah it hasn’t ever said any intervals unfortunately, and I’ve had the car for nearly 30k miles.

Speaking of the dealer, if my car was doing all that it would have been to the dealer days ago.....and I do ALL the work on my car myself.

"Crunching"?! Loss of power ON ONE WHEEL?! Just sayin' is all......

I don't think this is the source of your issue, but just for reference I had a quick look in the owners manual (the second book containing the maintenance history) and for my 2009 car the intervals are specified as Rear Diff Fluid every 40,000Km and both Transfer Fluid and Transmission Fluid every 100,000km - my manual spells out exactly what is required for each and every 10,000Km service.

loss of traction/activating ABS/uneven pavement will make a crunching sound with my family's '12 KIA sportage. it's traction control is not as advanced as Acura's systems and seems to be very sensitive, making the crunching sound every time loss of traction/activating ABS/Uneven pavement occurs

I suspect, like RL09, the AFS sensor

Thanks for checking that out for me! So it’s definitely something I need to do, but probably not the root of the problem, got it.

It just seems strange to me that the Adaptive Front-lighting System could cause the VSA and SHAWD lights to come on, not the other way around, and if it was just the AFS sensor, wouldn’t the AFS light come on alone? Does the light tilting sensor somehow play into the vehicle stability assist and all-wheel drive systems?

:what: Where did i say i suspect the AFS sensor to be the cause? :rofl:

Yea no, ur right. The AFS sensor does not cause all that. It merely goes on. It certainly doesn't make the wheel lose traction. But it will lose it's eyesight if neutral position memorization is missing.

Oh and just for the hell of it, make sure your engine oil level is fine.

im bad at reading. lol sorry guise. i didnt know the AFS stood for active front lighting. :tomato:
what I was getting at, it may be a sensor for the ABS/traction control/wheel sensor
as the '12 kia grinds on uneven surfaces, and when I heard that sound for the very first time, I THOUGHT something was seriously wrong. but it's just the way the ABS or traction control on the KIA works.

^Get it together crabman!!! :rofl:

Solved
 

Hey everybody!

Just updating you all after all the awesome advice you gave me. I ended it up taking my RL to the dealer and it turned out to be my very first original feeling: the steering angle sensor. They had to replace the whole assembly, so it ended up just under $500 for me. Could have been worse for sure.

Thank you everybody for all your help 👏🏼👍🏼