When CEL / MIL Code on Dash Differs From Scan Code on OBDII Reader

[SSTJ]

Has anyone ever had different results when taking this approach and comparing the results with a scan tool?

When I use the MIL approach (on the dash), I get three DTCs. When I use my scan tool, I get only one.

Should I just get a new reader?

 

[Jerry Bransford]

What are your 3 TJ generated DTC codes? If two of them are a '55' and '12' codes they're really the two that are ignored. 55 just means no more codes follow and 12 just means the battery has been disconnected at one point. Does the third code agree with what the scanner says?

 

[SSTJ]

What are your 3 TJ generated DTC codes? If two of them are a '55' and '12' codes they're really the two that are ignored. 55 just means no more codes follow and 12 just means the battery has been disconnected at one point. Does the third code agree with what the scanner says?

Great point, and sorry not for clarifying. In addition to 12 and 55, the three codes are 31, 42, and 65.

I have other threads about each of those, so I know what they mean, etc. The scan tool only tells me 31.

 

[JEEPCJTJ]

My 2005 Dodge Ram has had various codes for various different reasons and it seems to always depend on how I got the codes as to what they might have been. One time I had three codes from turning the key on and off but my son's OBDII reader only showed one. I'm not sure what the repair shop used to read the codes but whatever it was it gave far more detailed info and they were able to fix it fairly quick.

And FWIW I hate electronic BS no matter what. Do I sound like Zorba? I hope I do.

 

[TJ Jim]

My 2005 Dodge Ram has had various codes for various different reasons and it seems to always depend on how I got the codes as to what they might have been. One time I had three codes from turning the key on and off but my son's OBDII reader only showed one. I'm not sure what the repair shop used to read the codes but whatever it was it gave far more detailed info and they were able to fix it fairly quick.

And FWIW I hate electronic BS no matter what. Do I sound like Zorba? I hope I do.

So a skirt is next?

 

[TJ Jim]

My 2005 Dodge Ram has had various codes for various different reasons and it seems to always depend on how I got the codes as to what they might have been. One time I had three codes from turning the key on and off but my son's OBDII reader only showed one. I'm not sure what the repair shop used to read the codes but whatever it was it gave far more detailed info and they were able to fix it fairly quick.

And FWIW I hate electronic BS no matter what. Do I sound like Zorba? I hope I do.

So a skirt is next?

 

[SSTJ]

My 2005 Dodge Ram has had various codes for various different reasons and it seems to always depend on how I got the codes as to what they might have been. One time I had three codes from turning the key on and off but my son's OBDII reader only showed one. I'm not sure what the repair shop used to read the codes but whatever it was it gave far more detailed info and they were able to fix it fairly quick.

And FWIW I hate electronic BS no matter what. Do I sound like Zorba? I hope I do.

Ok, thanks for sharing. I might try another reader just to see what happens.

 

[SSTJ]

Great point, and sorry not for clarifying. In addition to 12 and 55, the three codes are 31, 42, and 65.

I have other threads about each of those, so I know what they mean, etc. The scan tool only tells me 31.

@Jerry Bransford any thoughts? Ever seen this? I'll order another scanner to try, but that'll take a few days to arrive.

 

[Jerry Bransford]

@Jerry Bransford any thoughts? Ever seen this? I'll order another scanner to try, but that'll take a few days to arrive.

The cheap one I bought at Harbor Freight Tools has been working great for years for me.

 

[JEEPCJTJ]

So a skirt is next?

A Skirt? MAYBE on Halloween. (and that is a big MAYBE).

A Kilt? I've never worn one but it does have possibilities on any day that I wouldn't freeze my nuts off.

 

[hear]

I have an OBDLink CX and I've seen cases where it shows more codes than what my Harbor Freight Zurich reader shows. Not sure I've seen it on my TJs, but I definitely had an XJ where my reader returned stuff I had never seen on any other reader.

And while I'm at it, i'll put in an unsolicited plug for the OBDLink CX. The app is pretty easy to use and is well-featured, and overall works better than any such device I've tried. The top seller on Amazon is BlueDriver. A friend has one and it isn't nearly as nice or easy to use as mine.

 

[JKP]

I'll order another scanner to try, but that'll take a few days to arrive.

You can just go to the auto parts store and have them scan it for free to compare.

 

[hear]

You can just go to the auto parts store and have them scan it for free to compare.

The most annoying thing about that is that they have to bring the thing back inside and plug it into the POS system to read the codes, then you have to stand there like an idiot while Mateo stands there like an even bigger idiot while he takes 15 minutes to figure out how to read the recommended resolution off the screen.

 

[SSTJ]

You can just go to the auto parts store and have them scan it for free to compare.

Good reminder, thanks.

 

[SSTJ]

I have an OBDLink CX and I've seen cases where it shows more codes than what my Harbor Freight Zurich reader shows. Not sure I've seen it on my TJs, but I definitely had an XJ where my reader returned stuff I had never seen on any other reader.

And while I'm at it, i'll put in an unsolicited plug for the OBDLink CX. The app is pretty easy to use and is well-featured, and overall works better than any such device I've tried. The top seller on Amazon is BlueDriver. A friend has one and it isn't nearly as nice or easy to use as mine.

Thanks, I’ll check that out. Looks like it is designed specifically to work with Bimmercode app. Do you use that one?

 

[hear]

Thanks, I’ll check that out. Looks like it is designed specifically to work with Bimmercode app. Do you use that one?

Nope, they tell you to use the OBDLink app. Although it probably works with lots of OBDII apps. I think they lean into the fact that it does work with Bimmercode, which is apparently a key marketing bullet point for their target demo.

 

[SSTJ]

Well, just when the OBDLink CX arrived, the CEL turned off so no more MILs. We'll see if it comes back this weekend.

 

[SSTJ]

Well, the CEL came back on yesterday. This time only two codes instead of three. Tried the OBDLink CX and only got one of the two. Oh well, for now I'll just rely on the MIL and what I can read in the FSM or online about the codes it shows.