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Discussion Starter #1
Hi All:

So if my thread title seems a little dramatic, it's not...just totally dumbfounded this morning... Some background...

Earlier this year, my only car was an old Volvo XC90 SUV with AWD. That thing has been rock solid and dependable, but after getting an AWD error, and a couple of big snowfalls, I realized that driving that car in Canadian winter weather was not great, especially with three kids, one of which I have to haul every week to church youth group out in the middle of nowhere in a little villa on country roads. (almost went into the ditch twice when I wiped out and I drive like a grandpa). I brought the Volvo to a Volvo specific indie shop in Toronto, and six weeks later and many, many visits and days off work later, not to mention over $3000.00 paid for both replacing parts and diagnostics, they told me they could not fix the AWD system. First time in like 20-30 years of their shop's existence. I was planning to live with it, but that was still in the middle of winter...so I decided to get a 2004 MDX at the beginning of March and I loved it so much that I decided to get a 2008 MDX at the end of March.

Both cars have driven very well and there has not been any problem. I have been told that the MDX AWD system is great, and it certainly is, and I assumed the days of AWD errors were behind me.

So you could not imagine my shock when I started my car this morning and go this big CHECK SH-AWD SYSTEM in big orange letters on my dash. I am not the type of person who uses curse words, but let me tell you, my mind's vocabulary was like something out of a Joe Pesci/Robert DeNiro conversation from the movie Casino.

It is a 2008 MDX with Nav/Sport/RES. The vehicle has always been serviced at Acura and service records are up to date. I can take a lot of funny errors on the car, but the AWD errors are not one of them, given the problems I had with my Volvo not that long ago (I have since sold the Volvo next to nothing).

Any ideas as to what could be wrong? I plan to get it scanned by my mechanic. Please share your experiences if you have encountered this issue especially.

Thank you.
 

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Jeremy,


There is a typical alarm in these cars where the culprit is the switch in the break pedal. Try that one first. It happened to me and many more before.


Pedro
 

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Discussion Starter #3
Jeremy,


There is a typical alarm in these cars where the culprit is the switch in the break pedal. Try that one first. It happened to me and many more before.


Pedro
Thanks Pedro. Would this be picked up when my mechanic scans it? My mechanic specializes in Acuras and Hondas, so that is good to know, but I am just so sensitive to this particular issue due to the past Volvo issues with the AWD (multiple modules send offsite for rebuilder testing and a couple had to be rebuilt and it was just a nightmare of try this and try that...I am hoping the Acura does not turn out to be like this, but when I saw that I was like, "oh no!!!"

I should add that it has been raining non stop and raining hard in Toronto area for the past 24 hours. Not sure if that has anything to do with it. My Dad also had it and put gas in it (I hope premium) and I will check the gas cap to make sure it's tight. But he drives like the grandpa that he is - plus I got the car back last night from him and there were no problems till this morning. AWD is definitely off because when I switch to the AWD monitor on the MID, it shows only power to the front.
 

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If it's not the brake pedal sensor, my money is on one of the wheel speed sensors located on each corner on the hub. This sensor detects the wheel turning and sends that signal back to the ecu and that's how it detects any kind of slip and thus affecting the awd system.

Any mechanic that has a good scanner able to tap into the Acura's ABS module should be able to detect this in their scan.

For some reason the passenger rear has been known to go out the most.

If the awd system isn't working properly due to a wheel speed sensor, it goes into FWD only as a fall back. I've driven like this for a few months and doesn't harm anything, as a worst case scenario.
 

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Don't fret too much, any vehicle needs a little TLC every now and then...
 

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Discussion Starter #6
OK so here's a weird one... just thought I would rule out some of the stupid possibilities...so over my coffee break an hour ago I went to my car and turned it on. Check SH-AWD System still there. Arrgh...so I tightened the gas cap just in case my Dad did not tighten it when he put gas in. I turned the car and turned it back on and the error went away! So I was aha, dumb gas cap. I drove and got my coffee, parked, and when I got back to the car and turned on, the error was back. Arrrgh. So I tightened the gas cap again, turned off the car and turned it back on. Error went away. Drove around. Turned car off and turned on again and error back. I am totally stumped. The gas cap thing may be purely coincidental. This will drive me nuts all weekend.
 

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Thanks Pedro. Would this be picked up when my mechanic scans it? My mechanic specializes in Acuras and Hondas, so that is good to know, but I am just so sensitive to this particular issue due to the past Volvo issues with the AWD (multiple modules send offsite for rebuilder testing and a couple had to be rebuilt and it was just a nightmare of try this and try that...I am hoping the Acura does not turn out to be like this, but when I saw that I was like, "oh no!!!"......

The scanner will tell the SH-AWD needs attention. The scanner will not point at the break switch. However, the break switch is an input sensor to the SH-AWD system. And that is why, in most cases, the break pedal switch is the culprit. Go for the break pedal switch and that is an easy DIY swap.
 

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Discussion Starter #8
The scanner will tell the SH-AWD needs attention. The scanner will not point at the break switch. However, the break switch is an input sensor to the SH-AWD system. And that is why, in most cases, the break pedal switch is the culprit. Go for the break pedal switch and that is an easy DIY swap.
OK cool...any chance you can either send me a thing on how to replace it or explain it to me? I am not a mechanical or technical guy though.
 

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Sure, I will give you a hand. It is very easy to replace and the switch auto-adjusts. There is no way to mess up the installation if you are able to remove the electrical connector without breaking it. LOL


If you want, give me a couple of hours 'till I get home and I will confirm with the service manual. Do you know what is the specific code in the nav screen?
 

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Discussion Starter #10
There is a code on the nav screen? I am only seeing the message on the MID. How do I access codes on the NAV screen? Most of the time I have the NAV screen off.

Thanks again, Pedro for your assistance. Whenever you get home and have time and can look it up, if you can look up the part number I need from Acura as well that would be great.

Very easy to do something and my name are mutually exclusive. Remember, my level of mechanical aptitude resulted in this on the MDX:

1. warping the positive terminal nut by overtightening thereby causing it not to tighten and getting my car towed less than 24 hours after owning it. My mechanic cut off the terminal clamped a new and better one on.
2. overtighening the engine air filter screw, thereby breaking it. Thankfully 3 out of 4 are still intact
 

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Press INFO in the console (by the round button) and select MESSAGES in the screen. I want to make sure I am not getting confused with the VSA system and the break switch.


The other way is to enter DIAGNOSTIC menu by simultaneously pressing "MAP/GUIDE"+"CANCEL"+"MENU" for few seconds until the menu appears on screen. The select "XM(HIP)" -> DTC LOGG"
 

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Discussion Starter #12
Thanks Pedro. Well, I managed to check while on coffee break and none of the options you mention above are there.

On the diagnostic screen, the options are:

Navi System
Monitor Check
Unit Check
Car Status
GPS Information
YAW Rate
Tire Calibrate
Functional Setup
Version

No option of XM(HIP)

On the Info Button, here is what I see:

Cellular Phonebook
Calendar
Calculator
Voice Command Help
Map Legend

No Option for Messages

Check SH-AWD System still on MID. It is still raining hard outside. Initially it went of and I drove to get my coffee without the error but after I parked, got my coffee and restarted the car, the error was back.
 

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Okay, I see XM (HIP) is not be available in Canadian models.

What I found is when you have the SH-AWD alarm, your vehicle is operating on FWD only and the SH-AWD system is disengaged. So, get the specific codes to continue looking at the possible cause. I was remembering the break pedal position switch might be more related to VSA alarm although it is a signal that goes into the computer and might be used for more functions than the VSA and cruise control.

Looking at the SH-AWD electrical connections, the control unit gets inputs from YAW-RATE sensor, ABSOLUTE STEERING sensor, VSA MODULATOR CONTROL UNIT which in turn gets inputs from WHEEL SPEED sensors, DIFFERENTIAL FLUID TEMP sensor, and PCM (Power Train Module). This SH-AWD module gets power from fuse No 3 (60A) in the main under-hood fuse box, fuse No 9 (30A) in the rear fuse/relay box, and Fuse No 20 under driver's under-dash fuse box. There is a SH-AWD RELAY in the rear fuse/relay box too.


Start by checking all those fuses and get a code.
 

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You have the NAV so go to messages and in Diagnostic Info you should have the specific OBDII Codes, That will help us out to help you further..

In my case last month a very short trip triggered a bad 02 sensor which also triggered a Check SH-AWD System.. How is the emissions tied to the SHAWD? God only knows but it will disable it for some reason... I also heard a weak battery can trigger a SHAWD disable since the Differential uses powerful magnets to send power to the wheels it needs a good healthy battery.
 

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You have the NAV so go to messages and in Diagnostic Info you should have the specific OBDII Codes, That will help us out to help you further..

In my case last month a very short trip triggered a bad 02 sensor which also triggered a Check SH-AWD System.. How is the emissions tied to the SHAWD? God only knows but it will disable it for some reason... I also heard a weak battery can trigger a SHAWD disable since the Differential uses powerful magnets to send power to the wheels it needs a good healthy battery.

Yes, a weak battery will prevent the SH-AWD from operating. If I remember well, Jeremy's battery is brand new!!!
 

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Discussion Starter #16
You have the NAV so go to messages and in Diagnostic Info you should have the specific OBDII Codes, That will help us out to help you further..



In my case last month a very short trip triggered a bad 02 sensor which also triggered a Check SH-AWD System.. How is the emissions tied to the SHAWD? God only knows but it will disable it for some reason... I also heard a weak battery can trigger a SHAWD disable since the Differential uses powerful magnets to send power to the wheels it needs a good healthy battery.


Unfortunately I do not have a messages option in Nav - see previous response where I listed what I see. And my battery is a brand new AGM battery so it will not be battery related


Sent from my iPhone using Tapatalk
 

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I only saw the response to the special Hidden NAV Menu (XM HIP, etc), But I was talking about the normal NAV Menu messages. Its where you get the messages from the dealership and the OBDII codes from the Check Engine.
I dunno if they changed even that for the Canadian Model but in my MDX that´s where I get the Codes Pop up in the Diagnostic Messages in the NAV Menu (Normal Menu not the hidden one).
 

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Discussion Starter #18
Unfortunately i dont have that feature in my MDX. Maybe once I get my mechanic to scan but even then the message would be on his tool.

The message on the MID comes and goes today. Wont get mechanic to scan until next week. Thanks for all your input. This forum is super.


Sent from my iPhone using Tapatalk
 

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The error has been gone for 2 days now. Weird. Happened to co-incide with the massive rain stopping. So before the 24-hour-straight rain, I never got this error. Got it during that time period. When I started drying up Saturday the error came and went. It was not there all day yesterday when it was dry and today when I drove into work the message was no longer there. So it appears to have occurred during the heavy rain. What on earth by it raining would cause the AWD error to come on? I am glad it is gone but don't like now knowing what caused it.
 

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Perhaps a non-properly sealed electrical connector that is getting water splashed. Now that is dry with low humidity level (my guess) the water in the connector has dried. That is my lucky guess.
 
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