Unable to read OBD2 scanner.

[Theguitarzombie]

I have a 2005 Yukon XL that have sat for 3 years when the check engine light came on. It started right up after charging the battery after sitting for 3 years, but runs a little rough. Suspecting the gas, I put high test gas in and I tried to read error codes (my inspection guy was able to read them three years ago). The reader would not connect to read codes, but the reader was able to do battery checks. I checked each fuse in fuse box, all ok. I checked the reader in other cars, it works.

I would like to try other things before spending the big bucks. Any thoughts, suggestions?

 

[nonickatall]

Did you ever used this reader on the Yukon? I would try to use another reader.
And I would check all the mass points to make sure that the electric system works.

 

[Theguitarzombie]

Did you ever used this reader on the Yukon? I would try to use another reader.
And I would check all the mass points to make sure that the electric system works.

Anticipating the obvious, in my original post, I wrote, “I checked each fuse in fuse box, all ok. I checked the reader in other cars, it works.”

is this what you meant in your reply?

 

[rockola1971]

Check for corrosion at your OBD2 port. If you have a substantial amount of gas in the tank that had been sitting there for the 3years then its octane has broken down to almost nothing. You need to add some E85 which is around 110+ octane or some octane booster in a bottle. Just adding fresh gas does not make up for the bad gas in there that has almost no octane to it. Wouldnt hurt to add some HEET also (Alcohol based water treatment).

 

[nonickatall]

Anticipating the obvious, in my original post, I wrote, “I checked each fuse in fuse box, all ok. I checked the reader in other cars, it works.”

is this what you meant in your reply?

No, I mean. You have to check the ground points because that is sometimes a problem at our cars and if your car is three years out of service, probably you have corrosion on grounds, grounds are not fuses, aren't they. ;-

And if your reader works on a lot of other cars, it doesn't mean that it works on this car. So I would check another reader, if it works on your Yukon.

I've seen weird things in the past, at electrical system of cars...

Two days ago for example I found the error which I was looking now for one year. My rear view camera sometimes does not work. But when I knock on the dashboard, it works sometimes, so it must be Problem at the radio, where the camera is connected in. I was looking there, checking all the connectors, the wire harness and everything, I didn't find any reason for the problem. So ein decided the camera must be a problem and I bought a new one to swap the old one. So I was looking where the current for the camera comes from, and i saw that it was connected to the rear gear light. My former owner of the car crimped that cable with isolation, so it has a to high resistance and I had only seven Volts at the camera. That was the reason, the camera sometimes don't work.

But tell me why the camera then work, when I knock on the dashboard...

A glitch in the matrix?

 

[rockola1971]

No, I mean. You have to check the ground points because that is sometimes a problem at our cars and if your car is three years out of service, probably you have corrosion on grounds, grounds are not fuses, aren't they. ;-

And if you reader a works on a lot of other cars, it doesn't mean that it works on this car. So I would check another reader if it works on your Yukon.

I've seen weird things in the past, at electrical system of cars...

Two days ago for example I found the error which I was looking now for one year. My rear view camera sometimes does not work. But when I knock on the dashboard, it works sometimes, so it must be Problem at the radio, where the camera is connected in. I was looking there, checking all the connectors, the wire harness and everything, I didn't find any reason for the problem. So ein decided the camera must be a problem and I bought a new one to swap the old one. So I was looking where the current for the camera comes from, and i saw that it was connected to the rear gear light. My former owner of the car crimped that cable with isolation, so it has a to high resistance and I had only seven Volts at the camera. That was the reason, the camera sometimes don't work.

But tell me why the camera then work, when I knock on the dashboard...

A glitch in the matrix?

When you knocked on the dash it moved the wiring that powers the camera which in turn moved the wires at the crimp (which Im assuming you mean a crimp on butt splice) and that caused a connection at the crimped butt connector....temporarily.

 

[nonickatall]

When you knocked on the dash it moved the wiring that powers the camera which in turn moved the wires at the crimp (which Im assuming you mean a crimp on butt splice) and that caused a connection at the crimped butt connector....temporarily.

Than i must be Hulk, because the bad connection was on the rear gear lamp at the back of the car.. So i made a shockwave through the whole car...

 

[Theguitarzombie]

Check for corrosion at your OBD2 port. If you have a substantial amount of gas in the tank that had been sitting there for the 3years then its octane has broken down to almost nothing. You need to add some E85 which is around 110+ octane or some octane booster in a bottle. Just adding fresh gas does not make up for the bad gas in there that has almost no octane to it. Wouldnt hurt to add some HEET also (Alcohol based water treatment).

Thanks, good advice. I did add some highest octane gas, it didn’t seem to run better. I read that the codes, if I could read them, might indicate the problem, like indicating errors that may be caused by bad fuel filter. But I’m thinking, why would the fuel filter be the problem just because it wasn’t run? So, my thought is to get to the point to read the codes. Possibly a bug chewed through a wire as there were **** roaches living inside. But I didn’t check corrosion, but the reader was able to do its built in battery check function.

 

[rockola1971]

Than i must be Hulk, because the bad connection was on the rear gear lamp at the back of the car.. So i made a shockwave through the whole car...

The second you put your bodyweight onto a vehicle, everything moves. Even the drivehsaft. You slightly compress the suspension with your bodyweight and there is no telling what is rubbing against what or what harness just got flexed enough to loosen an already partially dislodged connector even further. Even at the rear bumper.

 

[rockola1971]

Thanks, good advice. I did add some highest octane gas, it didn’t seem to run better. I read that the codes, if I could read them, might indicate the problem, like indicating errors that may be caused by bad fuel filter. But I’m thinking, why would the fuel filter be the problem just because it wasn’t run? So, my thought is to get to the point to read the codes. Possibly a bug chewed through a wire as there were **** roaches living inside. But I didn’t check corrosion, but the reader was able to do its built in battery check function.

You seem pretty novice to this. Not listening is going to make it even harder. The mere fact that this vehicle sat for 3 years with gas in the whole fuel systems explains plenty why the engine is running so bad. I personally would yank the fuel filter out (if equipped) and drain the tank jumpering the fuel pump wire at the OBDII port terminal or pulling fuel pump relay and jumper it there. That bad gas in there isnt going to get better unless dilluted enough with good gas and likely alot of octane booster at the very least. Its easier just to get rid of it.