OBD 2 Scanner gets power but does not read codes?

FLSL2019

MEMBER
2007 AUDI A8
4.2L
V8
4WD
AUTOMATIC
90,000 MILES

Hello, hope y'all enjoying Labor Day Weekend!
I was driving around the other day and my check engine (MIL) light came on and stayed on. So, with my very basic knowledge, I decided to get an OBD 2 Scanner on Amazon and go DIY. I got a cheap scanner Motopower MP69033 ($25!) And plugged in to the OBD 2 port under the steering wheel and it powered up fine using the car's power. Kept ignition in the "on" position before that per the instructions. It has a VIN button. When I clicked on it, I tried to scan but said "connection failed". I also hit the "DTC" button on the scanner which I believe should throw the error codes back at me but again same message "connection failed".
Before I can blame the cheap Motopower scanner, could it be that there's no power coming from the Audi's ECM? Perhaps to the OBD port. Maybe it's a fuse issue.
Is there like a certain quick thing you can suggest that I can check and make the scanner retrieve the codes?
Appreciate Ya'll help! Cheers!

5 Replies

JACOBANDNICKOLAS

MECHANIC
109,716 POSTS

Hi,

The issue isn't the scanner or the vehicle. The idea that you have power to the scan tool indicated the DLC is fine.

Here is the issue. On the lower-end Audi vehicles, a standard scan tool will work. On the A8, most times, they won't. You need a scanner designed for VAG (VW/Audi Group) or Vagcom, which is a program that operates on windows, via a computer.

Before buying a scanner, make sure it is compatible with the A8. Audi likes to keep things limited on this model so they can keep the cost high. LOL I had a 2005 that I loved, but finally got rid of it. It wasn't the easiest thing to work on.

Joe

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Sunday, September 4th, 2022 AT 8:08 PM

FLSL2019

MEMBER
3 POSTS

Hey, thanks for the response! That's interesting and makes sense. Is there like a VAG Scanner you can recommend that is "reasonably" priced.
Another thing is the check engine light disappeared a couple of days ago, and randomly came back on yesterday. Wonder if it's a fuel cap issue (I do click it closed). But if I have a reasonably good VAG scanner, I can at least read the codes and decide what to do. I know a good German cars mechanic I trust but they get so busy. Otherwise, my A8 L drives very well and I see no issues in drivability or decreased performance etc.

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Thursday, September 8th, 2022 AT 12:46 PM

JACOBANDNICKOLAS

MECHANIC
109,716 POSTS

If it is still running well, chances are it is something like an evap leak. I don't know where you are located, but in PA, we have to test fuel caps as part of the emissions inspection. Maybe someone could inspect it for you.

As far as VAG com, that is a program that is loaded onto a computer. There are scan tools, but I'm out of touch with what is out there. I will say that you will likely get your best deal from Amazon. Check it out and let me know what you find.

Let me know.

Take care,

Joe

PS: You are really making me miss my old one. I loved that car.

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Thursday, September 8th, 2022 AT 7:02 PM

FLSL2019

MEMBER
3 POSTS

Hey Joe, I did get a chance to show it to the mechanic. He ran his more sophisticated scanner:)) and said it's showing as running lean. But looking into it further he said it's actually running a bit rich. Even though the check engine light is on he showed the reading on the scanner as (negative) -6.2 which he said is still ok. Usually if it's between -10 and +10 he said that's ok. They will recommend deeper diagnosis if we see something like -25. I believe Audi designed the car to be perfect with strict ranges (which is a good thing if my understanding is right. Solid engineering! I would think it was coming from AUDI).
So I asked if I should keep driving it. He said that's ok and bring it in if you feel something feels changed. But also, we talked about if he can diagnose this a bit more like my next service (which I want to do at 95K miles, I am close to 89500 miles now). The last service (oil change etc.) Was done by Safford Hyundai dealer (here in VA) at 87000 miles. I'll probably take it back in before winter hits and see if they can actually fix the lean/rich issue.

Good to know you are from PA! Do you like near Philly or Pittsburgh? I am from VA (near Washington DC). I am a car and motorcycle enthusiast but not very "mechanically inclined". After I purchased the Audi a couple of months back, recently I got myself a Yamaha Stratoliner (my new toy lol).
I totally know how it feels to miss a vehicle you sold. Hope you are driving something fun now.

Regarding the VAG scanner, I'll look at Amazon etc. Thanks for explaining that stuff.

Best regards,
Sunny

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Friday, September 9th, 2022 AT 8:50 AM

JACOBANDNICKOLAS

MECHANIC
109,716 POSTS

Hi,

I'm near Pittsburgh. As far as fun to drive, I still have my A4 Cabrio. It's getting old but still runs and drives excellently.

He is correct about the trims. What you indicated is acceptable. In a perfect world, you want them to be 0, but that usually doesn't happen.

I would do what he suggested. See if it continues running properly. If there is a change, then it will need attention.

Let me know if there is anything I can do to help. By the way. I never had a street bike. I do, however, have two dirt bikes. LOL

Take care of yourself and let me know how things turn out.

Joe