Free OBD-II readings and Normal Measurements

[Nate1]

I need to know of a place that will read my OBD-II codes, basically pending ones since I don't have a CEL light right now.... and if anyone knows them, what are the acceptable values for oxygen sensors at idle (warm).... or any other sensor that you could think of causing my rough idle (MAF?)
Thanks a ton, I only have till 5 oclock.
-----Nate

 

[dogfriend]

I think that Autozone will scan for you, I don't know of anyone else.

There is no "set reading" for the O2 values, they switch back and forth going above and below .4 Volts. .4 Volts represents the "ideal" air fuel ratio, so the injector timing is adjusted based on the feedback from the O2 sensors. However it is like aiming for a constantly moving target, the voltage never stays at .4.

The main thing you want to see from the O2 sensor(s) is that they are switching back and forth. If they are switching too slowly, this should set a code (and CEL) with OBD II.

 

[Chris4x4Gill2]

Yea...AutoZone will do the scan for you and look up the code on their computer. Besides that they aren't much help. As in they don't know what you need to do to fix what the code told you.

 

[Robb]

YEP, if you get AutoZone to do the codes, thank them and walk away. If they start to say, "you got code blah blah blah.........you need to replace your blah blah blah," don't listen to them. They are pretty infamous for telling you that you need the wrong part. Get your codes, then search for them here. If you can't find them in a search, then start a thread with the codes you got.

Robb

 

[Nate1]

Already bought a Haynes for my own code retrival. I will wait for a CEL, but I am almost positive my idle problem is a bad oxygen sensor now. It is doing the exact same thing it did when bank2 upstream kicked the can. I'll just have them scan the CEL (if/when it happens in the next week), just to make sure it is P0131-P0135 or P0151-P0155
I supppose I might also need to watch for PO505, but that is less likely. Mabey a misfire too.
Anyways, thanks, and I will report what I find.
-----Nate

 

[Robb]

Already bought a Haynes for my own code retrival

I don't think you can pull the codes with OBD-II without a reader/scanner. The Haynes manual gives instructions for OBD-I.

Robb

 

[Nate1]

Ohh I know that , I meant I got the manual so I could look up the codes among other things (Like see how to test/replace O2s and IAC)
-----Nate

 

[dogfriend]

The Ford CD manual (look on Ebay) has a lot more info on what the codes mean and what to do about it than the Haynes manual does. You should check this out if you don't have one already. The price on Ebay is between $8 -$15.

 

[BradE.]

AutoZone scanners will NOT be able to monitor O2 sensor values on Fords. So unless you have a hard code (CEL) or pending code they won't be able to tell you anything.

Ford uses a special coding and Mode for their O2 sensor values, most cheapo scanners (including AutoZone's) don't have the proper mode to read the values. They have the same problem with Fuel Trims. Even the $300 AutoXray units don't read the values correctly. I purchased an OTC Monitor 4000 Enhanced (professional scanner) and it performs ALL the O2 functions and fuel trims, but it's also a pretty expensive unit.

 

[Robert]

My AutoXray scanner with Ford Enhanced OBD-II support will read O2 sensors values and fuel trims. As long as Autozone uses an AutoXray with enhanced OBD-II support they can monitor them. Before the upgrade, all I got was 0.000V on all O2 sensors and -100% on all the fuel trims. Now I can at least get readings under the enhanced menu.

 

[Explorer_guy]

Yeah, my Diagtek scanner can read the Ford O2 and fuel trim right. I'm glad I've got a scanner designed for Fords and not just generic one.