ECM issues...gotta replace it

in the final stretch getting all the little thing taken care of post SAS on my tacoma. My work schedule doesn't allow me a lot of time to play with it so progress has been slower than I would like.

one of the preexisting issues with this truck when I bought it was a low voltage code on the one of the AFRs. I have already eliminated the O2 itself and the wiring harness by fallowing the diagnostic procedures outlined in the FSM to a "T". I had some slight doubt in my diagnostic skills so I got a second opinion with out giving him any suggestions prior to dropping it off. My second opinion comes from a Ford Master tech but he was trained at a non-brand affiliated school. with him using the FSM and doing his own diagnostic he came to the same conclusion, the ECM is bad and will need to be replaced.

according to our diagnosis the ECM is either not send enough voltage to the O2 or not getting enough voltage back.

I have all ready spoken to all three of the local dealerships and the price for a new ECM with install and a diagnosis of their own is $950 and up. I am entertaining the possibility of buying a ECM from ebay.
my question is if I match the year, engine, and trans is the is the ECM play and play or is the ECM in the 05 Tacoma have security protocol like some other vehicles where it will need to be flashed before the ECM will play nicely with the body control module, security module, Ect.?

does any one see any pro or cons to using a $100 Ebay ECM versus a $850+ dealership ECM?

input and technical information are valued and welcomed

thanks in advance
Josh

 

A computer replacement on a 2nd gen is EXTREMELY rare.

What code are you getting?

I'd throw a sensor at it before a computer. There's been multiple times at my shop that a 02 will test fine with voltage and resistance, but still cause issues. Replacement has always cured the problem.

I work at a Toyota specialty shop, PM me if you have any questions.

 

In addition, the computer will need to match part #'s to the T if it is in fact a faulty ecm.

 

connections and harness as well as sensors have all been checked to factory FSM standards using their recommended test procedures. in the name of thoroughness the it has been done by my self and two other certified technicians (outside of the dealership). the O2 have been changed several times using O2 and AFRs from the dealership and just to be completely sure I pull the wiring harness de-loomed it and visually inspected every wire, every connector, and every pin termination in those connectors.
like most I find it very hard to believe that a toyota ECM has gone bad or been damaged , but it is what the diagnostic has produced for three separate people.
unfortunately my tuck has the engine immobilizer on it so it looks like the FSM should recommend Vaseline as the tool of choice for my trip to the dealership.

But a short history lesson. I bought this truck in Mississippi frame a Navy guy about to PCS to Hawaii the CEL had been present the entire time he owned it and I was told the original and previous owner had the code for a while as well. the guy I bought it from lived in a county that only requires safety inspection on any vehicle and he wasn't the most mechanically inclined either since I had to bleed the brakes for him prior to test driving it, logic dictated the previous owner didn't really know that much either from what I saw of his built skills. my thoughts at the time were they were unable financially or skills limited to fix it and were not in a position where they had to fix it.
the absolute thing I thought it would be was a ECM…so I bought it

now several year later the build is done. I am quite proud of this truck now and am hell bent to have it fixed. my biggest concern with taking it to the dealership is how heavily it is built. I have played the games with dealerships before and I am well aware the first thing they will say is it is because it modified.
My general tactic is that I am going to take it to them and go ahead and pay the diagnostic fee. let them futilely do all the stuff that has already been done by myself and two others. I am not going to give them any hints or even tell them its been looked at by multiply competent guys. I want them to come to their own conclusions that way if they come up with the same fix as I did the EMC and they are wrong they are on the hook for it not me. if they fix the issue with out with out replacing my ECM my ego may be bruised but I am sure my wallet will appreciate it

does any one have any suggestions or see a flaw in how I am approaching this?

 

Do you have experience with crank / no start? Possibly Gulf State Alarm system? Turning key to ON position, the check engine light does not come on. Does the alarm system disable the ECM computer?

My original post: https://www.tacomaworld.com/threads...rt-bad-accessory-wiring.681847/#post-24049465