Can't read my OBD-II
 

I went to get my emissions tested on my 1996 Caprice Classic. The
testing facility in IL couldn't read my OBD-II computer. Any way to
check what's going on? Took it to the shop and they couldn't read it
either. What could be the problem? I can't pass emissions without
having it fixed and I don't want to put $1000 into a care worth only
$3000. The car works fine. They just won't test the emissions manually.
For 1996 and later they check the OBD-II. Any help greatly appreciated.

First thoughts a See if your Check Engine light comes on with KOEO,
then goes out shortly after starting the engine. No MIL can be a
simple indicator of a VCM problem. To go further you will need to
check continuity of the data wire(s) from the VCM to the check
connector under the dash, and that they don't short to ground. Check
that B+ and ground are present in their respective terminals, too. If
everything looks good so far, you could look at the data transmission
with the key on using an oscilloscope. It will look like random pulse
width square waves if any data is being transmitted.

Toyota MDT in MO


wrote:
> I went to get my emissions tested on my 1996 Caprice Classic. The
> testing facility in IL couldn't read my OBD-II computer. Any way to
> check what's going on? Took it to the shop and they couldn't read it
> either. What could be the problem? I can't pass emissions without
> having it fixed and I don't want to put $1000 into a care worth only
> $3000. The car works fine. They just won't test the emissions
manually.
> For 1996 and later they check the OBD-II. Any help greatly
appreciated.

1 check that you engine check light is coming on when the key is in the on
position. If it does not come on - 1st thing is to check all the fuses as well
as the one under the hood. any 3rd party add-ons. ever have a radio system or
the likes installed in the vehicle?

Next I would check for power going to vehicles engine computer. I'd also check
that the unit had a good ground connection. if everything checks out ok then
I'd say your cpu is toast -- and I would recommend that you take it in to a
qualified auto tech for inspection

--
BBA

The 1st Law of the Internet -- http://www.cavebear.com
When Privacy Matters -- http://www.epic.org/
> wrote in message
oups.com...
> I went to get my emissions tested on my 1996 Caprice Classic. The
> testing facility in IL couldn't read my OBD-II computer. Any way to
> check what's going on? Took it to the shop and they couldn't read it
> either. What could be the problem? I can't pass emissions without
> having it fixed and I don't want to put $1000 into a care worth only
> $3000. The car works fine. They just won't test the emissions manually.
> For 1996 and later they check the OBD-II. Any help greatly appreciated.
>

Sure the car's build date is 1996? GM cars of build date 1995 can be a
bit odd -they can have an OBD-II connector, but an ODB-I computer..
They're not easily tested by most generic places - you'd need a
custom cable and a laptop (or take it to a dealer)

>Sure the car's build date is 1996?


And if like dcg suggests, your car turns out to be OBD-I, the inspector
will run it on the dyno to check for emissions. That is my current
understanding of IL IM240 testing.

If your Caprice is a 1996 on the door tag and the emissions sticker
under the hood and by VIN then it is legally OBD-II compliant and does
not qualify for dyno testing under any circumstances.

Toyota MDT in MO