Unable to read check engine codes, ALDL only has 2 pins !!

[BoringLumina]

OK, went to check codes last night and my under dash diagnostic port only has metal contacts and wires in the A & M locations (Top row and bottom row rightmost column) Is there any way to read codes? Grounding out A & M does nothing !! I pulled the bottom of the dash apart and I do not see that any wires were hacked out of any of the wire harneses, there is electrical tape around the two remaining wires and contacts like somebody did surgery.

Any ideas??

Whops, forgot to add: 1995 with 3100 V6 191,000 miles OBD 1

[SappySE107]

what year?

[Cool_The_Slain]

I think that 94 and 95 cars were obd 1.5. I couldn't read codes on my 94 tdc, and auto stores with scanners said that they couldn't because it was inbetween obd 1 and 2, so I had to take it to the dealership to get my codes read, all for the lousy egr of course. I think some scanners can read them, but they were pretty expensive when I looked at them.

P.S. This is what my ALDL Looks like, I'm pretty sure that the pins you short out on the obd 1 are on the left, but I don't remember because it doesn't concern me.

[BoringLumina]

Bummer, other than the dealer is there any hope of getting this car scanned?

[Cool_The_Slain]

Well, when I had my problem some people listed scanners that could do it, but unless you want to spend $400 or something like that I'm pretty sure you are out of luck.

[TrailMug]

Pin M is an 8192-baud bi-directional TTL link. The "paper clip" dtc read circuity had been discontinued, and you have to read the data stream to get DTCs. I'm actually working this out right now with my 91 cutlass. (i have the 'paper clip read' functionality still, but i want data like BLM, INT, etc, etc..)

There is a simple schematic available for interfacing your M-pin to a computer's serial port (http://syclone.invisibill.net/cablewires.gif). Software suchas EFILive or CarBytes, etc, etc, is necessary to issue the "Mode 1" command to the ECM to retrieve trouble codes and other info, then read and interpret the stream. It might be hard to find a package to interpret your car's specific data feed, but it may be possible for you to write one (what i'm doing). Great info on interpreting the data feeds can be found at http://syclone.invisibill.net/cablewires.gif

[TrailMug]

agh pasted the second link wrong.. that should be http://www.efitune.com/data_streams/

[TheProfessor]

take it to advanced auto i had a 94 retta with the non-grounding diagnostic type 12 pin and they pulled the codes for me with a scanner

[BoringLumina]

Yeah, I took it to AutoZone and the guy said that the OBD2 scanner would not work, given the shape of the connector I believe it. I will try an advanced auto, what should I ask for? I am guessing that all scanners are not equal and that an OBD2 will not read OBD1 or 1.5 stuff.

Thanks Guys

[geoffinbc]

On OBD II scanner (like a Tech II which you will find at a dealer) will read all computers. Just take it to a dealer. If the service depertment has some half descent humans in it they will do it for free. My dads dealership does it all the time.