Reprogramming a used ECM for 2nd Gen Tacoma (2007)???

Hello,
I have a 2007 Tacoma (6 cyl, TRD) that just one day would not start. Cranks well, no start. Have gone through all kinds of diagnostics (fuses, relays, grounds, fuel pump, injectors, computer has power and grounds good, etc). I have reached the point that there is no signal going from the computer to the coils. Crank Sensor checked and appears to be working just fine. Looking at getting a used ECM from a wrecker and wondering if anyone knows if these require reprogramming to match my VIN? If so then is this something only the dealer can do or are there others around Ottawa, ON Canada that can perform this. First dealer I called said I need to have truck towed in with the new to me ECM installed and then they will re-program. Ughhh.

 

You can reprogram the vin via a MINI VCI usb cable and techstream (I have done it at home on a spare ECU that I have). You will also need to do the immobilizer pairing

 

Thanks. Sounds beyond my skill level unfortunately - any idea of anyone around Ottawa who does this sort of thing ?

 

It will run without changing the VIN but the immobilizer reset has to be done before the engine will start.
You do need to get an PCM with the same part number (Printed on the PCM) as the one in the truck.
The VIN Write can be done at a later date, some aftermarket scan tools will do it (My

$959 Autel MS906BT / DS808/ MP808S/ MP900/ MP808BT PRO, ECU Coding Bidirectional Scan Tool, VIN/License Scan, 40+ Service

Autel MS906BT will).

Have you verified you have power and ground at the coils? Are you getting any codes?

 

This is true, do the immobilizer reset - relearn and it should run without issue (got my truck up and running before doing the vin flash)

 

Sound like ECM doesn't recognice your key immobilizer.... do you check when you turn key on and light immobilizer went off?
JustDM definitely can help to rewrite VIN number to new ECM, I got mine done with him.

 

Thanks - I was able to locate a ECM with the same number (89661-04C41) as the one in the truck. Yes, we verified power and ground to the coils. For some reason there is no communication from computer to coils. I don't have the codes that were pulled but recall it was saying there was a problem at all 6 coil packs.

 

Yes we thought that might have been the case at the start of this mess but the light immobilizer goes off when you put the key in the ignition so it seems to be recognizing it as a good key. Thanks for the lead on re-writing VIN

 

Ah that would be P0351-356, yea the truck typically would be a start/stall if it sets codes for all 6 coil packs at once. You need to make sure the IGF circuit isn't shorted to ground on either a wire or one of the coils.

There should be 5v on the IGF circuit key on engine off, see my description of the P035x codes in the thread below.
https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042157

 

Here's the ignition coil wiring, IGF would be on Pin 24 of connector E4 at the PCM on your truck.

 

Thanks - in my case we are just getting a crank / no start situation (not a start/ stall). I don't think we are getting a Ignition Timing Signal from the computer.
One other weird thing that happened a few weeks before this no start situation - my 4WD lights started flashing like crazy on the dash when driving in 2WD. Won't engage when you try to put in 4H or 4L either. Not sure if this is at all related to my crank/ no start issue I have now...

 

Yea the IGT signal can only be checked with an oscilloscope, I have seen Toyota PCMs fail it's just not that common unless they get water in them. That's why I always question when someone says they have a bad PCM if they have verified everything else is working right.

It could be, the 4wd system shares some grounds with the PCM and engine system.
Got a writeup for that too lol.

https://www.tacomaworld.com/threads/4wd-system-operation-help-thread.742420/

 

So I received the used ECU (which was verified to be working), installed it in the truck today, completed the Immobilizer reset procedure as written but still no success. Same lights show up on dash, cranks well but no spark. Really don’t want to tow to the dealer!!! Any last suggestions? If computer is getting power then that means the ground to it should be good right? Someone mentioned checking grounds but I don’t know where to start on that one. I am sure that we’ve already checked ground to computer but maybe there is another one that should be checked.

Attached a photo of the lights that come on when cranking. 4wd (green light) and 4LO flashes, ABS and e brake light, tire pressure monitor.

 

Did you check the IGF circuit like I said?

 

We checked the IGT but not the IGF. The IGF would not send the confirmation back to the ECU unless the computer sends the IGT to the coils right? Still worth checking the IGF circuit?

Injectors are operational and fuel spraying (confirmed with plug out)

 

I would seing as you have P035x codes, at least check the key on voltage. The IGF circuit should have 5v on it key on engine off with everything plugged in.

 

I’ll give that a shot when I am able to. Big snow storm coming tonight and the truck is outside. Pardon my newbie lack of knowledge but what does it mean if the IGF circuit is good and what if not good? Where would those scenarios lead ? Thanks!

 

If it's good (5v on the circuit key on) I would want to double check power and ground at the coils with a headlight bulb to ensure the circuit can carry a load (I'm assuming you checked it with a meter?).
If it's not good (not 5v key on) start unplugging coils one at a time until it returns to 5v, if it still doesn't then find the J12 connector (see my thread), unplug that, and test for 5v on Pin 4. If you have 5v on Pin 4 with it unplugged you need to test Pins 5, 9, 10, 11, 12, & 13 for a short to ground and repair it.
How did you test the IGT circuits?

 

Great info for (hopefully not) future reference. Thanks to all.

 

UPDATE/ RESOLUTION
MY mechanic Paul did more diagnostics as mentioned and turned out to be the computer ground for the coil (???). He grounded to the body and the truck started right up. Now if I can only solve my 4LO light flashing for no reason when drivign in 2WD and inability of truck to go into 4 LO or H if I try to turn the control.