Hi
I am having problems with my truck and when I plug my code reader, no codes are registered even though the MIL is flashing. Then it occurred to me to check the label under the hood. It does not state obdll compliant but "Conforms to Canadian Emissions act". So, does anyone know if it is obdll or not and if no one knows, where could I find the answer?
Don

 

A 97 is OBD2.

Is your CIG fuse good?

A flashing CEL means misfire. Check out the P030x thread in the OBD2 Code Listing link found in my signature.

 

The reason I am asking if it is obdll compliant is because I don't have the sticker on the car. OBDll became mandatory in Canada in 98. I called 3 GM dealers and none could tell me for sure. I have to pay to have it sanned on the Tech2 to be certain. I have the 2 O2 sensors unpugged, the MIL flashing indicating misfire and no stored codes. I don't think this is normal!! I ordered a pc scan tool (Elm5) which I should get begin of next week. Hope this tool works!
Don
PS All fuses ok

 

Every 96+ produced s-series truck is OBD2 compliant.

What are you using to determine that no codes are stored? Does the scantool indicate that it is properly connected to the vehicle (i.e. that it can communicate with the PCM)?

 

That is also what I was thinking. I am using an Inova 3100 code reader and it is communicating and will read some codes if I unplug sensors. I just received my Elmscan5 and went out to try it. See results below. How many wires shoud go to the DLC and what is their color code?
Don

 

Well, I got my hands on diagrams for the DLC and VCM. I tested the #4, 5 ground points and #2 serial data link for open or shorts. Everything seems fine. Tried different scan tools (borowed from frends) and same thing. They either state not compliant or does not conform to any standard and I can read some, but not many pid's. I wonder if the fact that my O2 sensors are not plugged could have an impact on this. Will try again tomorow and if it is still the same, will try to find support on the GM website to get an answer. BTW my VIN is 1GKDT13W0V2565346 in case this helps someone resolve this issue. And also, I did try the scan tools and decoders on other cars and they work perfectly.
Don

 

possible issue with the PCM itself instead then?

 

At this point, I guess anything is possible. It was raining here yesterday and again today. I will call a GM dealer and see if they can test it on the bench without costing an arm and a leg. Thank's
BTW, the scan tool does show that it is using J1850VPW protocol. I don't know if this protocol was used before obdll!!

Don

 

J1850VPW (VPW = variable pulse width) is the OBD2 format that GM vehicles use.

 

I might have found something but I don't know how to decypher this. Can someone help?
Don