miataroadster

I saw a"CODE KEY" OBD II CODE READER at Costco for less than $30.Has anyone tried this unit? The reason I'm asking is because my check engine light is on. As from previous experience, I checked the gas cap(r/r)restarted the AR but the light is still there! Anyway, maybe i still need to run a few more miles before it resets itself? This is the second time it happened since I bought her last month so I think it's a cheap investment to buy the OBD unit.
Btw, there is no loss of power, shaking, or anything like that when the light came on. Any input?

paulroad

it will only tell you OBD info.. not VAG and allroad specific info, save the ## and get a VAG COM Cable and a laptop.

miataroadster

Thanks for the reply! I am new to this vag thing. Is it a fortune to get one? Is this something I can get from Pep Boys or Wal-Mart?

paulroad

http://www.ross-tech.com/vag-com/hex-usb+can.html

thejulex

Of course you could also get ebay VAG-COM cable for $20 and it would probably serve you well since I doubt you'd require any advanced functions full version provides.

Older version of ross-tech VAG-COM software (409.1 is it?) works with eBay VAG-COM cables and allows to read and reset codes.

miataroadster

weird- I drove about 110 miles yesterday to visit my sis. hooked up the ar using the codekey(yes, i bought one!) reading says P0175. however when i restarted the ar this morning the check engine light no longer lit. seems like it's probably the gas cap, again????

paulroad

Not weird at all.

Your picking the Gas cap is only one of MANY REASONS you will get a CEL. Its a comon malady because not everyone remebers to tighten it.

Here are some others that relate to P0175:

* The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters can cause the MAF to become dirty if the filter is over-oiled
* There could be a vacuum leak.
* There could be a fuel pressure or delivery problem

Possible Solutions

Possible solutions include:

* Inspect all vacuum and PCV hoses, replace if necessary
* Clean the MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner
. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
* Inspect fuel lines for cracks, leaks, or pinches
* Check the fuel pressure at the fuel rail
* Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
* Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)
++++++++++++++++++++++++++++++++++++++++++++++++++

Now.. the CEL and its codes are STORED in the ECU's memory. When the fault CLEARS ITSELF the light will go out. Ie.. if the 02 sensor was faulting and now its OK, then the code will eventually clear until and if it happens again.


I'd say your problem has NOTHING to do with the gas cap. You need a regaul VAG related scan.. return the POS for $30.00 that you are using to scan a $50,000.00 car that has more systems and intersections than any of us can imagine.

If you want to diagnose and DIY then learn and follow the advice that others are giving you. It isn't your gas cap :-)