Failed emissions -> no connection to computer

[hardcorejohn]

Hi all,

I recently took my '97 cobra in for required emissions. They connect to the odb II port and get the emissions info that way rather than from the tailpipe. I was failed because they could not connect to the computer (fuses were checked).

So I took my code reader and no codes thrown, however in the "I/M" section, all sensors were "Not applicable" where they should be either "Ready" or "Not Ready", which is perplexing to say the least.

Any ideas on where to start or what could be causing this?

 

[chuck943]

Check Pin 16 Y wire in the data link connector for batt V first

 

[mineralgraygt]

check the fuse for the dlc it should be on the same circuit as the cigarette lighter

 

[screamin gt]

have you replaced the battery lately? or even just unhooked it for a period of time?

why I ask.... I have an f150 that has a badd emmissions sensor, had to go through emmissions, so I had the code turned off.

went through, had them tell me that same thing, computer aborted the test. of course it did the truck hadn't been driven enough to decide if it was running right or not.

drove it for 100 miles or so, and went back to test. passed. then a few days later got the bad emmissions sensor code back again

same thing could happen if you disconnected the battery, it may not have enough info for the test yet, so if you drive it for a week or so and go back for the test you should be good.

 

[rebelleader]

have you replaced the battery lately? or even just unhooked it for a period of time?

why I ask.... I have an f150 that has a badd emmissions sensor, had to go through emmissions, so I had the code turned off.

went through, had them tell me that same thing, computer aborted the test. of course it did the truck hadn't been driven enough to decide if it was running right or not.

drove it for 100 miles or so, and went back to test. passed. then a few days later got the bad emmissions sensor code back again

same thing could happen if you disconnected the battery, it may not have enough info for the test yet, so if you drive it for a week or so and go back for the test you should be good.

If that were the case his Computer would say 'Not Ready'

 

[hardcorejohn]

Check Pin 16 Y wire in the data link connector for batt V first

12V through pin 16. High current fuse for the cig. lighter checks out ok, actually all fuses check out ok.

Any other ideas/ next steps? Thanks in advance for the help.

 

[chuck943]

Well so much for the easy stuff.
Now you will have to check the wiring from DCL to PCM.
Pin 4 BK & 5 BK/W of DCL connector are grounds.
Pin 13 P of DCL goes to pin 13 of the PCM
Pin 2 T/O of DCL goes to pin 14 of PCM
Pin 10 PK/LB of DCL goes to pin 15 of PCM
Ohm these wires make sure they are good

 

[hardcorejohn]

Well so much for the easy stuff.
Now you will have to check the wiring from DCL to PCM.
Pin 4 BK & 5 BK/W of DCL connector are grounds.
Pin 13 P of DCL goes to pin 13 of the PCM
Pin 2 T/O of DCL goes to pin 14 of PCM
Pin 10 PK/LB of DCL goes to pin 15 of PCM
Ohm these wires make sure they are good

Thanks for the info Chuck, can you let me know the location of the PCM? I guess I could trace the wiring but this might save me a little bit of time. Thanks.

 

[chuck943]

behind right hand cowl panel

 

[hardcorejohn]

Well so much for the easy stuff.
Now you will have to check the wiring from DCL to PCM.
Pin 4 BK & 5 BK/W of DCL connector are grounds.
Pin 13 P of DCL goes to pin 13 of the PCM
Pin 2 T/O of DCL goes to pin 14 of PCM
Pin 10 PK/LB of DCL goes to pin 15 of PCM
Ohm these wires make sure they are good

Well I looked at the connector, I have pins on locations 2,4,5,7,10,13 and 16.
Here are the values I got for the different pins to ground.

ground -> pin2  162 ohm
            -> pin7   infinity
            -> pin10 445 ohm
            -> pin13 1153 @200k ohm setting (for all intents infinity)
            -> pin16 170 ohm

I also think I have found where the wiring leads from the foot area. It is by the cowl panel in the engine bay on pass. side. I see a harness that seems to have the same wire colors as the connector it leads to somewhere else that I haven't traced yet.

 

[chuck943]

PCM is inside car behind the right interior kick panel up inside the cowl or pillar,If I remember right you have to about stand on your head to see it. You will have to disconnect the connector to PCM and ohm wires from DCL to PCM connector to see if you have any open circuits and also check them for short to ground and power while the connectors are disconnected.