Engine computer pooped!!!

Friends 99 Tacoma engine computer up and totally quit at 2:30 AM. I have ordered a new one, but need to know just how difficult it is to get them swapped out. I read that they are behind the glove box. Does anyone have any additional information regarding this? Tools needed? Any specialty items or stuff to watch out for?

 

Going to play devils advocate here; how do you know the pcm quit?

What if it's a bad ground or something causing some weird/no start situation?

 

Cause it was running perfectly fine and just straight died. Took it to shop and it’s showing no communication to the scanner. Haven’t done anything but changed fuel pump cause I thought it was fuel pump. No spark, no fuel pump prime, but it does crank over fine.

 

Try a different scanner.

 

A $16,000 snap on scanner needs to be tried with a different scanner?

 

Many 1st gen owners wrench on their own cars and have done so on other cars as well.

Start with basic trouble shooting steps before throwing money at it all because a scanner told you to do so.

 

Truck is totaled. You’re right. Adios.

 

I tried it with my cheap Bosch scanner. Same thing. No communication, link error.

 

Check your fuse panel for a bad ECU fuse or any blown fuses. Thread on resetting the ECU below.

One of my cars has a fuse that is connected to the ECU and radio antenna. When the antenna fuse is blown, it loses connectivity to the ECU. So I learned to check all fuses when something strange with the ECU occurs.

https://www.tacomaworld.com/threads/how-to-reset-ecu-by-removing-fuse.494600/

Here's a vid about replacing the ECU if you need this.

https://youtu.be/5-t69mMpazg

 

I did basic trouble shooting.
No spark
No fuel pressure
No fuel pump priming.
Battery is good and hot @14.7v dc
Checked every fuse in the truck.
All are good.

that is why I trailered it to be scanned.
2 different scanners show no communications.

 

thank you. That helps a whole lot.

and I checked all the fuses in both fuse boxes trying to find one blown. All were good.

 

I had to replace one in my M3. It’s not hard to replace them. It’ll take you longer to get to it. Clips should be similar and are the ones where you slide the “hood” up or down and the clip slides in or out . Sorry, best way I can think to describe it.

 

While they do fail about the only thing that takes them out is water and a huge Voltage spike

Been doing any welding with the battery not disconnected ?

Been using the truck underwater?

As for as changing them plug and play 10mm nut driver

 

I watched the video. That gave me a really good idea what to expect.

 

it’s not my truck. But she does use it for a newspaper route. Recently had a bad alternator replaced, then a bad battery replaced. Fortunately both items had lifetime warranties and did not cost her anything to fix but an hour labor on the alternator and nothing for the battery.
No welding done to the truck at all best of my knowledge.

 

Already did that. I have a bunch of fuses from scrapped vehicles and I swapped them all out. Still the same.

 

Turned out it is a fuse that is blown.
But it keeps blowing them as soon as I turn on the key.
AM1 is the control circuit for fuel and engine computer.
AM2 is for the starter.
I replaced AM1 with all the way to a 50 amp and it popped every one.

I will have to go get more fuses cause I went thru all the new ones in the pack I JUST bought. And I don't have any more spares.

Does anyone have any ideas or suggestions as to where I may be able to start checking for this dead short I am encountering?

The owner is considering it dead for a while unless I can miraculously find the problem area and get it going again.

All the fuses I had replaced are the mini-fuses I had on hand. I did not have any like the one for AM1 and AM2.
So to those who suggested the fuses, I must apologize. I did try them, eventually!

 

Hope to learn from you.... After replacing the fuse. (could you please identify which one it was) Did you figure out what was causing the dead short? Did someone connect the battery cables to the wrong terminals. (that's what it sounds like to me.)

 

If you need a ecm they have all different Pinouts and or plugs every year, engine , Trans and 2wd or 4wd

 

Already have a second ECU. Matching numbers for both units.

The vehicle has some kind of a dead short in the ecu/fuel circuit that the fuse goes to. Bad part is I don't know how elaborate the wiring is to chase down. I put a pair of needle nose pliers in where the fuse goes is how I established it was an actual bad fuse. The engine actually tried to start when I tried the key. That's when I got the new fuses. But all of them are now blown. I don't want to catch the truck on fire trying to chase down the short.

I have moved the truck out of the garage for now. But will work on it more this weekend to try to chase down where the short is at. I also plan to swap back the original engine computer and see if it might possibly be that.