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None of these connections looks like a Diagnostic Port
My diagnostic port is not attached to the main fuse/relay box, and is supposed to be on the driver's side under the hood. I have three ports there, and none of them seem to look like what I see in a number of videos that I've watched. Please see the attached picture. Any comments on how to proceed? Thanks.
My diagnostic port is not attached to the main fuse/relay box, and is supposed to be on the driver's side under the hood. I have three ports there, and none of them seem to look like what I see in a number of videos that I've watched. Please see the attached picture. Any comments on how to proceed? Thanks.
Could you please narrow it down to the year and engine much easier to describe the plug shape and wire colors for you to look for.
The 86 22re engine has 5 different connectors for testing
The FSM has a monster, four-page fold-out (and not the fun type of fold-out) wiring diagram. I looked through it carefully, and I saw no no reference to the diagnostic port. I'm wondering what I missed.
Thanks
Glen
You can see the color of wires going to the second connector matches the colors of the cut wires. Someone probably cut it to wire in a switch to make check the codes easier.
That's actually a cool idea. I could mount it on the engine wall and flip the switch at will. I have a follow up: there is a process for pulling codes when the CEL is intermittent, but that requires the more advanced diagnostic port which is attached to the engine fuse/relay block. How do I pull intermittent codes using the two-wire connector? Thanks.
It has been a while since I worked on the early 22RE fuel injection system, but most early fuel injection computers store codes for a certain amount of key cycles. I am thinking that the codes will be stored even if the light is off, you should just check it using the standard procedure as soon as possible. The more advanced connector is only on the later 22REs.
Will do. If I find an ECU from a newer-model parted Yota, can I swap it in and get better diagnostics, or better anything else for that matter? Thanks.
I have never tried that swap, but I would think some of the wiring would have to be swapped along with some of the sensors. I doubt it would be worth the effort. If you were going to swap the wiring and the ECU, you might as well look into a 3RZ swap. If you just wanted a more modern engine management system, you could probably look into something like Megasquirt. I have never set that up, so I do not have a lot of input on that, but I know a lot of people use it for engine swaps with good results. Are you having a specific, hard to diagnose problem with your truck?
Sort of. Apart from the intermittent CEL, I'm also seeing that the previous owner chopped a few wires and left some connectors simply hanging. The FSM wiring diagrams give few clues about the actual locations of things, and far too many descriptions online use words rather than pictures to explain where things are. So I'll see a loose connector in the engine compartment and not have any clue as to what it is. I figured the engine codes might at least add some clues. I have no problem doing my homework and background reading, but I'm not sure precisely what that homework is. Cheers.
Now I see what the problem is! That sounds like a pain. The best advice I have is see if you can find someone with a similar year truck to compare engine bays or take notes at the junkyard. Posting picture here on Yotatech might help, also. Vehicles that have been pieced together and 'modified' by many previous owners can seem like a never ending project to get right. If the wiring has been cut, disconnected, etc., chances are sensors and other electronics may have been mis-matched, which could contribute to your intermittent CEL. Good luck!
Sort of. Apart from the intermittent CEL, I'm also seeing that the previous owner chopped a few wires and left some connectors simply hanging. The FSM wiring diagrams give few clues about the actual locations of things, and far too many descriptions online use words rather than pictures to explain where things are. So I'll see a loose connector in the engine compartment and not have any clue as to what it is. I figured the engine codes might at least add some clues. I have no problem doing my homework and background reading, but I'm not sure precisely what that homework is. Cheers.
The Complete FSM also had a separate book the Electrical Wiring Diagrams This shows all the circuits wire colors locations of relays and sensors .
Keep looking around before Toyota Sold the Service Manual rights To Helm inc they could be bought at a decent price from Toyota Publications.
To me a must have for any electrical work.
To me upgrading to a newer OBDI system is a waste of time any money you would need the complete engine harness and ecu plus all the sensors or have the EWD for both year vehicles and go through the engine harness circuit .
Swap to a newer engine 1996 + with the OBDII system gives you the option of running a scan gauge and watching live data.
08-01-2021, 05:40 PM
