Bump-Starts and runs great, won't start with key - P0335 - ECU replacement fixed

I'm really just at a loss here, if this were at the shop I'd probably be calling a bad ECM but you said you tried the replacement one and had the same result?

 

Yup, I hooked up the new ECM without removing the old one (dangling in the air), tried again and got an identical healthy crank with no start, all instruments light up. I didn't try bump starting with the new ECM since figured a crank means things are all right, but didn't verify that...

Minor thing since at this point, who knows: I often get static electric shocks when exiting the vehicle. Pretty sure it's the synthetic covers against my cloths that build up charge. Could that eventually damage anything other than the ECM? Figure it's negligible.

Another minor thing: as mentioned in my opening post this all started once I patched a large whole in the muffler, adding resistance to the exhaust. Could that affect any sensor? The problem started gradually, at first it just took longer each time to start (didn't notice if RPM was working though).

 

How did you path the hole?
welder?
Where was the ground attached?
Was the battery disconnected?

I can’t see how that made it happen?
But who knows?

I am still dreaming up ideas here.

 

ECM has nothing to do with it cranking, you can completely remove the ECM and it will still crank.

Let's plug in the replacement ECM and see if we have communication first of all.

 

Is there anyway you possibly got an ECM for a Canadian truck?
I believe the Canadian truck had the security system. Or at least some did.
If maybe that’s why the new ECM didn’t work.

Any chance we can get the part number?

AFAIK, none of the ECMs are locked. So they should let you start the truck.
The VIN will need to be changed, but the truck should still run.

That’s all I can think of right now.

Let us know if you can talk to the new ECM as Dm93 said….

 

How should I go about that? Engine light? OBD scanner?

 

Plug the ECM, turn the key on, and see if you have a CEL, if you do then plug the scanner in and see if it talks and what codes/data you get.

 

Ladies and gentlemen: PROBLEM SOLVED!

So firstly, since I changed the CKPS I stopped getting any Codes/Check Engine Light (not even bump starting).

I just hooked up the used/salvaged ECM I ordered online and it just started! OMG it WORKS!
I'm pretty sure I hooked it up correctly when I tried before, but I'm not certain 100% (didn't verify scanning or bump starting).

So it seems it was either the ECM only, or the combination of ECM and new CKPS that did the trick. Could that be?

Thank you everyone so much for the support, hope this fix sticks...
Let me know if you want anything else so this can be helpful to anyone in the future.

 

That's the best news I heard all day.
I sat around all day thinking of possibilities. And none I came up with really would have helped.

If anything, we learned 2 things.
2.5-3v waveforms IS enough to start the truck.
And that the wiring diagrams for 2007 is "correct" for all trucks.
As there is one ground wire missing form "some" or maybe ALL trucks.

Anyways, good news. Glad to see it is now fixed.

 

Nice, so we were correct in thinking it really couldn't be anything other than the ECM. I guess I should have pressed harder on seeing what the replacement ECM was showing but in any case we got some valuable info, know good waveforms, and learning experience, all it cost was some time.

I'd be curious to have a peek inside the old ECM and see if anything obvious looks wrong, just don't see many Toyota ECMs fail without help especially in weird ways like this.

As for the crank sensor changing things I can't say, the waveform looked pretty much the same per and post replacement so I have my doubts it changed anything.

You may want to edit your title to show it's fixed.

 

THAT IS AWESOME! I've been following this thread since it started!
Glad you got it working and a huge shout out to @Dm93 and @TnShooter
That's one thing I love about this site, a lot of (or a few) folks that really know their sh!t, willing to stay in the trenches with you until you get it figured out.
This is fantastic.
Please @hyharari , check back with us in a few weeks and let us know that the fix is still working. This type of activity helps team members in the future.
I don't mean to hijack, since I had nothing to offer, but this thread is 'full of win' for the Tacoma community.
Good sh!t.

 

So its been a while and the truck starts fine, knock on wood.

I've opened the ECM and noticed some diode or something probably burnt:


Some more pics:




On a slightly different note, since the new ECU/ECM I've lost a whooping 2 MPG on average.
Used to be running around 24 but now only 22 mpg, same commute.
I even changed all the oils (diffs, transfer case & transmission) and finally got an aftermarket (stainless) exhaust.
Thinking that would improve my fuel economy hence now am suspecting the ECU is the issue.

Going back to my ebay order, it seems from the pics (but I could be very wrong since the ad is still up with the same image) it was taken from a totaled 2007 TRD Pre-runner, opposed to my normal(?) 4wd. Any idea if that could cause higher MPG?

Any tips on improving fuel efficiency are welcome! Tuning of some sort? Performance Chip Module?

 

Yea something definitely smoked in the old ECM.

As for the lower MPG I couldn't tell you, ECM is the same between a pre-runner and 4wd as far as I know unless that one has a different calibration. It would be almost impossible to find that out though because Toyota does not publish calibration information except in TSBs that have calibration updates.

There's plenty of tuning support for the 1GR but I don't know if anyone is doing a tune for the earlier 2TRs or not as there isn't much left on the table for them performance wise.

No such thing as a "performance chip" that plugs into the OBD port so don't get taken by those scams.

 

AFAIK, the ECM calibration pretty much stayed the same on the 2TR trucks.
The 1GR trucks had some changes over the years. And for sure 2012 and after.

But the 2TR was basically all the same from 2005-2015.
Nothing much changed engine wise that I know of……