Won’t start. Fried computer after rain?

Went out this morning. Cranks and cranks but no start. Put in a new battery. Still no start and no change. Trying to pull any codes and it won’t let me. Just shows this.

 

starter turns the engine over?

 

I’m getting fuel. Fuses are all good. All electrical is good as far as wiring plugs coils. My buddy’s dad came over from his shop and brought his fancy code reader and even he couldn’t pull anything. It’s not even recognizing that the truck is on and it’s not communicating with the computer at all. He’s been a mechanic/tire tech forever now and owns his own shop and even he’s perplexed.

Theory:
We had a pretty heavy rain last night and I like most 1st gen owners have that issue where the rainwater somehow drains through behind the dash and drips out on the passenger floor. Only this time it was much worse. Usually there’s maybe a small puddle of it. I had taken my passenger seat out to let my dog have more space during a recent 8 hour drive so I put down a large blanket. That blanket was totally soaked this morning.

Is it possible that the heavy rain could have messed up the computer? Where should I go from here?
Thanks gents

 

Yes it wants to start but will not turn over. Cranks and cranks and cranks.

 

And this is also especially convenient since I was suppose to be starting the head gasket job but instead we’re doing this. I just wanted to park it in the damn garage lol.

 

Ok it looks like the ecu is pretty damn easy to replace. Is this a part that absolutely needs to be oem like LBJ’s or can I just pick up a Denso one from a Napa or something? Or should mine actually be able to dry out on its own?

 

You need the same part # ECM that you have now unless you want a major project.

The ECM and the Engine Harness and sensors are matched set

If your getting fuel the ECM is not completely fried.

The only way water can get in the ECM is through the plugs .

You just might have a communication issue .

What can it hurt at this point to pull it out take off the cover and dry it out .

Fresh water is not that good of a conductor so no fuses opened.

Good Luck!!

 

We found our culprit. Followed Timmy’s video. Luckily it was very easy. As soon as I took it out water came pouring out of it.

Now I’m planning on letting it sit inside somewhere near a heater and hopefully it dries out and works again by the 30th. What do y’all think the odds of that are?

 

Few areas in question? Or does this look normal?

 

I'd start with some electric contact cleaner and a soft brush.

I'd also start looking into some of the ECU refurb companies in the likely event that it's toast.

 

That looks like that’s been getting wet for quit some time…need to find out where the leaks coming from before replacing it

 

My first thought was, “you’re screwed brother”

then again, @Running Board Man had his taco completely running silent and fully submerged. He still brought it back - at least for a bit.

If you’re able to get it going, I would definitely be on the hunt for a replacement. I imagine electrical gremlins will be showing up at some point from the looks of that PCB.

Sucks, sorry to see this.

 

You have a bigger problem. To replace it you need the units number code, and the water damage destroyed it. The sticker on the unit that says 5VZ, the code is where the paper is Porked.

 

People were posting their ECU part numbers along with their truck specs here:
https://www.tacomaworld.com/threads/toyota-tacoma-3-4l-k-line-ecu-reflash-interest.502600/

Good luck.

You can use Isopropyl alcohol and a toothbrush to carefully scrub/clean the corrosion off. You can also use something like DeoxIT to clean and protect:

$18 Hosa D5S-6 CAIG DeoxIT 5% Spray Contact Cleaner, 5 oz.

https://www.amazon.com/gp/product/B00006LVEU/

 

This is what was available -



If we rule out by year, that leaves 2 possible PN's. His label shows a PN ending in 821. That leaves one -

8966104821

https://www.toyotapartsdeal.com/oem/toyota~computer~engine~control~89661-04821.html

This listing talks about programming the ECU with a VIN#. Since I know nothing about swapping ECUs, I'd definitely check with someone in the know (@Speedytech7 maybe).
https://www.ebay.com/itm/385304095780

Hopefully he can track one down and replace it after he gets that leak resolved. CA is in for another week of rain. Oh and I would still confirm with a decent parts department using VIN just as a sanity check lol.

 

89661-04821 for sale | eBay


I would make finding the leak 1st priority.....its either bottom of windshield or the vent cowl......
So much wiring in that area with the hvac and all the different harnesses all coming together right there........grand central station......

..good luck

 

Good lesson here is..... if you plan of keeping your taco for a really long time.....
it might be a good idea to secure a backup ecm........while still reasonably obtainable ....
especially if your blessed with one from 95 to 97 for sure......


should be a number of these floating around with current members here.....WTB in classifieds......
I bought one for a 2rz for $40........

 

50-50 it works !!

 

Toyota ECM ECU PCM Engine Computer Repair & Return Toyota ECM Repair | eBay

 

I really appreciate everyone’s feedback. I just called a Toyota recycling center in Sac and they didn’t have any in stock. My ecu is still sitting inside where it’s warm next to an air vent and will be there for another two days so we’ll see what happens. In the mean time I’m almost halfway through this head gasket job. My buddy is also looking for an ecu for me as well, he’s got a lot more connections than me.