2000 Taco w/3RZ Won't Start, OBD Link Error

I found some older posts about similar problems, but none had a real resolution. They were all a few years old, so I'll throw this out to see if anybody has any new ideas.

While driving on a rough dirt road, engine died and won't re-start had to be towed home. Here's what I've found so far.
- Engine cranks - strong battery, full tank of gas, acts like no spark/fuel
- OBD scan tool gets power from port but gives a link error. Tool worked fine a few weeks ago. Checked it on other vehicles and it works fine on them.
- When I turn on the ignition key to the run position the CEL doesn't come on as it normally would during the lamp check.
- All fuses are OK.
- Not sure if it's related but it's had a recurring P0171 (System Too Lean) code prior to this happening. Since I can't connect to OBD, not sure if the error is still there.

Has anyone had any success diagnosing anything like this without having to take it to a shop? Any suggested next steps?

 

First thing I would do is check all connections to the ecu. That ruff trail could have vibrated them loose.

 

my money is on broken ground leads at the intake manifold if OK the no CEL is telling you the PCM is got waking up. Disconnect the battery and unplug the PCM a few times, this should help clean the contact pins. then try it again.

 

Thanks guys for the suggestions.

Glamisman, I assume you're talking about the ground lead between the intake manifold and the chassis. Checked it and it's snug on both ends and the cable looks fine.

I also disconnected the battery and reseated the connectors on the ECM. No joy. Disconnected the battery, for the third time, and letting it sit a while before re-connecting.

 

Found some nice troubleshooting guides here: https://store.allcomputerresources.com/techtalk.html
They suggest disconnecting one sensor at a time to check for shorted sensors. While doing this found that the oil pressure switch wire had been routed between the exhaust manifold and the heat shield and the heat shield had rubbed through the insulation and bare copper was showing. Cleared the short and thought I had it, but still no joy. Pressing on.

 

Do you have interior power such as gauges, dome light, etc?

 

No connection to ECU truck wont start = bad ECU 99%

I have seen 4 diff posts past few months with same issue outcome being the same.

 

darn, hoping for the simple fix. I have attached the Toyota MY 2000 wiring. Seems complicated but it isnt really. Check powers and grounds at the PCM and it they are present then the PCM is bad.

 

Glamisman, thanks for the diagram. I have a similar one, but it doesn't include the description of each of the sensors like this one. It may be a couple of days, but I'll post the results of the power and grounds check.

 

no problem... on the very last page and the very last table is a listing of locations. If you need to locate any of these let me know and I will try to find the appropriate pdf file and upload it. The files I have are not indexed or linked so clicking on the Blue numbers doesnt take you to the appropriate location :[

 

I know this is an older post but was the resolution to this problem a new PCM? I have the exact same issue with almost identical problem, not to mention identical truck. Did all the checks that have been recommended in this thread to no avail, wanted to see if anyone knows whether a new computer solved the problem before I try purchasing a new one for my truck.