I have two OBD2 scanners, an old elm327 with a serial connection that was originally used on a Mazda Protege and a Subaru Legacy (where it fit with no issues), and a newer ElmScan 5 with a USB connector. The new one was just purchased, and is 7 years younger than the older one. Now we have a 2003 Civic Hybrid and a 1999 Accord. I couldn't get the older scanner onto the OBD2 socket of either car, and the new one just barely fits on, maybe halfway I have not yet powered it up to see if it works. I would be a lot happier if it went on all the way, until the casings mated properly. The old scanner had pins that looked a little thick, whereas the new one has pins as thin as any I have seen on a scanner. This is just strange, like Honda used a socket size that is a millimeter or two bigger than the outer "D" part of the male plug.

I have seen the Honda service people just slap on a handheld OBD scanner, but now I'm wondering if that might not have been a unit slightly special (larger) to fit their OBD ports.

Anybody else seen this? I think I might be able jam the new one on all the way by using a lot of force, but should not have to do that.

 

It probably is the reader/scan tool you're using than the Honda OBD-II/DLC port. The OBD-II scanner I have never had a problem on any OBD-II ports on any make of cars I used it on.

 

The thing is, the older scanner fit the Mazda and Subaru OBD2 ports with no issues. The same scanner does not fit either Honda OBD2 port. Since the scanner has a fixed size there must be some physical difference between the Honda port and the ports for the other two makes. As I mentioned, the pins on the older scanner were a little thick, so I though perhaps that was the issue, that the receptacles were narrower on the Honda. However, the new scanner, which is, as far as I can tell by eyeballing it, has a plastic housing that is exactly the same size as the old one, and has much thinner pins, doesn't fit either. So now I think the outer plastic part of the Honda port has slightly larger dimensions than the other makes.

I have a decent set of calipers and this weekend will measure the dimensions.

As a workaround I'm thinking I may cut slits into the scanner housing, so that the plastic can spread out to get around the slightly over sized Honda port.

 

It's not the Hondas, it's because you bought the absolutely cheapest scanner possible.

I use this one and have had no problems on any makes: http://www.mactools.com/product/tabi...9341-ET97.aspx

 

There are much cheaper scanners available, and the old serial Elm model was actually more than a typical handheld at an auto parts store.

So I made some measurements. Here are the values measured (in mm) for the dimensions A,B,C,D (see the attached image) on the two scanners, a drawing I found on the web of an OBD2 connector, and on the 1999 Accord. I used the Accord because it was easy to pop the port out and pull it down to make the measurements, whereas on the Civic it was jammed into a tight space and wouldn't easily come out.

The interesting thing, I thought, was that the drawing did not have a value specified for D, but it did for A and B. Both scanners were larger than the drawing and Accord for A and B, and they would have fit had those been the only dimensions that mattered. Their values for D (and as a result C) were too tight on the Accord, which is apparently why they did not fit well. It is pretty odd to not have all dimensions set by a specification marked on an engineering drawing, and I wonder if the OBD2 spec was a little vague about the dimensions for D, resulting in these fit issues. I don't think this is a "cheap" issue, since it would have cost no more to make the part used by the scanners a tiny bit wider.


In the end I was able to jam the Elm5 on tight enough for it to make an electrical connection, but it was still only about half way in. Probably if I cut the case on the scanner at the two sides of "D" with a hacksaw or similar tool it would go on all the way, since that is where it was binding.