2nd gen 2.7 immobilizer help

hello folks, I have an 80s toyota truck that I swapped in a 2tr-fe from a Canadian spec 2010 tacoma. it had a factory immobilizer but long story short, it got wet and died. so I figured I would do the simple thing and swap in a non-immobilizer u.s. spec 2.7 ecu however it wont run. after buying 2 more ecus and repeatedly banging my head against the wall I finally got ahold of a "good" scanner and I found code b279c "ECM for vehicle without engine immobilizer system is installed on vehicle with engine immobilizer system" my question is how does the ECU detect that the harness is a immobilizer harness. the 2 wires that run from the ecu to the transponder key ecu (imi and imo) are not connected and Toyota doesn't really have any info on how a non immobilizer engine harness is different from a immobilizer engine harness.

 

Are you in Canada or the USA ?

All parts being sourced in Canada?

I have no idea if the USA and Canada built trucks Engine Harness and ECM are compatible. Never having hands on one of those trucks . To late till find out till Monday Morning.

The easy way is match the Harness to the ECM without the immobilizer.

I am guessing the ECM is different in the way it is pinned. It must not be seeing a fed back signal from your disconnected wires. If you only needed to cut those wires to bypass the system .

With the EWD of all the vehicles involved you should be able to figure things out. Maybe ??

The Tacoma`s being Canadian built that opens a completely different can of worms

 

I am in the u.s. the donor truck was Canadian spec. I currently have a active subscription to TIS to verify all the wiring is the same. According to the schematics the wiring to the ecu is the same.

 

The PCM can't know the difference between an immobilizer equipped harness and one without, I wonder on ones without maybe IMO and IMI are shorted together? Maybe worth a try and see what happens.

 

that what confuses me. the schematics show no difference for the immobilizer engine harness and non immobilizer engine harness. I just shorted the imo and imi wires together and there was no change. the only conceivable thing I can think of is Toyota hid a resistor or something in the harness to tell the ecu its a immobilizer engine harness.

 

Not sure how or where, those 2 wires appear to be the only difference. What if you ground those 2 wires?

 

Does it start and stall or does it not even crank? I'm looking through my info now.
I would see about de-pinning these two wires at the ECM.

 

I grounded them. no difference

with the original immobilizer equipped ecu it will start then die, with the new non immobilizer equipped ecu it cranks but does not fire.

 

Did you clear the code and the same code is setting?

 

Have you tried de-pinning these two wires at the ECU?

 

yep I depinned them. no change.

 

What's the ECM part number that you are currently using?

 

the original ecu part # is 89661-04e80 the "new" ecu part number is also 89661-04e80

 

yep I cleared them and it will immediately reset as a history code and as a current code.

 

This seems odd as the only two wires I see going to the ECU from the immobilizer ECU are IMO and IMI. If the original ECU had an immobilizer and the new ECU part numbers are the same, then does the new ECU also have an immobilizer?

 

I checked it does not, according to the vin registered in the new ECU it's from a u.s. truck that didn't have a immobilizer. I even checked the options list in TIS

 

Are the trucks regular, extended or dual cab?

 

both trucks were access cabs.

 

Alright guys there is finally an end to this saga. first off if anyone down the road runs into code b279c you are screwed as I cant figure out what sets it and Toyota is really vague about diag info. Here's what I did to fix my truck I took the original somewhat sketchy ecu and desoldered the eeprom from it. I took the new ecu and desoldered its eeprom. I then soldered on the eeprom from the original ecu onto the new ecu, I hooked up the scanner and code b279c was gone and the ecu now has the vin number from the original donor truck written to the new ecu. I sourced a used immobilizer ecu from a friend with a key but for some reason the ecu wouldn't do the immobilizer learn with a paperclip. I am guessing thats because I have almost no original Tacoma wiring. I went ahead and did the same thing with the immobilizer ecu, I desoldered the eeprom from the dead immobilizer and soldered it onto the new ecu and bam! it started right up.

 

That's quite a fix, glad you figured it out.
More than the average person is gona get into for sure although I can't see many people running into this problem either as they would more likely be replacing PCMs with the same part number.