Elm Scan OBD-II Reader

[MJJ]

I just bought an elmscan reader to use on my '99 S70 as the mil light came on a week or so ago. Based on stories from this forum, I first checked the gas cap, it was tight. Then I suspected the O2 sensors. So, I was eager to see what Elm would tell me.

The first screen I checked was the codes screen. It was blank. I clicked 'read' a couple of times just to make my point but no codes ever displayed. Hmm, I think, maybe some config problem. So I checked the monitoring screen, which contained no data. I'm really thinking I have the wrong com port or some such by now. 'What does this Reset Chip button do?' I wonder, and click. Voila! Engine data is displayed. Back to the codes screen I go, and see... nothing. OK, back to the monitoring screens for further scrutiny. I notice O2 sensor 1 shows data N/A, and O2 sensor 2 seems to have reasonable voltages. Clue! I am off to my local Napa A/P to get an O2 sensor and will report back what happens.

Oh, despite no codes on the codes screen, clicking the 'Clear' button on this screen did in fact clear the mil light.

So, the question is: Has anyone used the ElmScan tool and seen codes come up? I'm sure that the O2 code is about as common and standard as they get so I'm surprised it didn't show.

(So far I don't fully agree with your hatred of PC based scan tools, Matthew, but it's far from perfect!)

[matthew1]

Oh no prob. But you'd join me if you saw my software's interface!

I'll read up on your tool later when I get a minute.

[MJJ]

Follow up:

First of all, Napa gave me the wrong sensor because their applications listing does not allow for the brief window in 1999 where the sensor is different. Had to go to the dealer and even they were stumped for a bit. Finally got the right sensor.

Brought it home and checked codes again. Came up with a P0135 which is O2 Sensor 1 Heater Open Loop (or something like that). Odd that this would supercede the sensor failure but maybe this is the primary failure after all. I can't know because I never got the scan tool to show me the codes when the mil light was on. But the Sensor 1 reading was still N/A.

So then I replaced the sensor. The sensor is easy to get to as it is on the exhaust down pipe. Just crawl under the car and don't confuse it with the one mounted on the catalytic convertor. The plug to the wire harness is a whole different story. Unless you have tiny hands and 4-foot arms it will be difficult. If you have large hands it will be impossible. I ended up removing the air cleaner box and unbolting the bracket holding the wiring clips in order to get access. Hint about the O2 Sensor 1 connector: there is a white retaining clip mounted on the loom side of the connector that rotates up to release the sensor side connector. Use a long screwdriver to reach down there and pry it up. Also there are times when lying under the car gives you a better reach up to the connectors than reaching down from above.

Now that the new sensor is in, the check engine light is still off (10-15 miles of driving on it) and no new codes are up. But, I am still getting N/A for my Sensor 1 reading, which given the erratic performance of my scan tool, and the potential for Volvo to design its interface in odd and unexpectedly proprietary ways, does not surprise me too much.

Does anyone have information about the sensor reading? Any ideas better than mine why it still reads N/A?