Failed smog due to computor not connecting to 97 4Runner

B

Bingo

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Howdy,

'97 4Runner wont connect to smog machine. It did connect to hand held diognostic machine but read in most areas that there is no info. Checked all fuses they were fine. Any ideas?
 
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Well that is odd.... the port is just a connector to the ECU. Does your truck run well? If so, then you can hopefully assume it isn't the ECU and is a connection issue.
 
Runs great and passed the smog part/failed to read vehical part

I have been looking into this online. Could it be the "drive cycle"? I'm wondering if it has to do with jump starting a Peterbilt (big truck) a few times and not being driven more then aprox. 50 miles since?

Whats weird is it gives a partial read on hand held dignostic but wnt register on the smog machine. I also went to 2 diffrent smog places...
 
It doesn't matter if you jump started a Wheel Loader or a Smart car, the ecu has no idea that you did that. So that is irrelevant to the issue.

I'd just pull the leads to the battery drive for 50-100 miles and see if it passes.
 
If the battery has been disconnected for a while, the ecu looses all the stored data. You will need to drive in mixed conditions (highway, city) for about 50 miles before going in for the emissions test.
 
This happened rather unexpectedly (in that it had worked, then stopped) on my wife's '96. It would connect to a hand held OBD2 scanner with no problem, but the state computer couldn't.

I got a wiring diagram for the plug, and started checking what I could. I found that there are two pins that are supposed to be grounded, and only one was. I probably should have traced that wire that wasn't grounded (but should have been) to see why, but we were in a bit of a time crunch (plates were expiring) so I just clipped it and grounded it behind the dash, near the plug. Took it back to the state, computer hooked up fine and it passed.
 
Bingo said:
Howdy,

'97 4Runner wont connect to smog machine. It did connect to hand held diognostic machine but read in most areas that there is no info. Checked all fuses they were fine. Any ideas?
Click to expand...

so i know this is random but i ran into this issue once on my camaro. I went to get it dynoed and they couldnt connect the tuning laptop to the OBDII port, i mean they could plug it in, but nothing registered. It ended up being on the same fuse as the cigarette lighter. The cigarette lighter fuse was fine, but the cigarette lighter wasnt hooked up anymore and so there was no circuit to connect. You may wanna look into that, or see what circuit its on
 
JohnMc said:
This happened rather unexpectedly (in that it had worked, then stopped) on my wife's '96. It would connect to a hand held OBD2 scanner with no problem, but the state computer couldn't.

I got a wiring diagram for the plug, and started checking what I could. I found that there are two pins that are supposed to be grounded, and only one was. I probably should have traced that wire that wasn't grounded (but should have been) to see why, but we were in a bit of a time crunch (plates were expiring) so I just clipped it and grounded it behind the dash, near the plug. Took it back to the state, computer hooked up fine and it passed.
Click to expand...

good to know in case i run into this, my sticker expires this month
 
I have a handheld ODBII scanner that is relatively new and it connects fine to my 5th gen and my 8 year old dodge and a couple of other vehicles I have checked for family/friends. But, when I connect it to my 3rd gen, it acts as if there is a short somewhere, similar to what is described in this thread. I basically have to wiggle the connector to get a decent connection and then do my best to hold it there with one hand while I work the buttons on the scanner with the other hand. Perhaps this is a common problem and is related to why the state computer can't connect and get a good reading. Do you have any idea if they tried to get it to work at all in this way or if they just stuck the plug in, got nothing, and sent you on your way?
 
In order to fail smog due to "Drive Cycle" the computer would have had to connect to determine that the vehicle hadn't been driven sufficiently after any reset to clear any existing code(s). the OP stated that no connection was evident. I would lean towards a poor connection or, as mentioned prior missing ground.

I got my scanner from cheap-mart and it take many tires to get it to connect to several vehicles. Oxidation of the pins may also come into play. Good luck
 
In order to fail smog due to "Drive Cycle" the computer would have had to connect to determine that the vehicle hadn't been driven sufficiently after any reset to clear any existing code(s). the OP stated that no connection was evident. I would lean towards a poor connection or, as mentioned prior missing ground.

I got my scanner from cheap-mart and it take many tries to get it to connect to several vehicles. Oxidation of the pins may also come into play. Good luck
 
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