So my beloved 96 4runner with only 111000k on it started acting up lately. It would just randomly die while driving but it would fire back up. So I cleaned the iac and put some dry gas in it. It ran great for 3 days and today in a blizzard it just died. It will crank but no fire. So I had it towed to the local dealership and they put an old timer on it. They are telling me that the ecu is not communicating and they are looking for $2200 to fix and replace it but aren't 100% sure that is it. Any thoughts from the Jedi Masters out there?

Seems odd that the ECM took a dump, I mean it's not out of the realm of possibility; just that this isn't a Chry-crap product that has bad modules on a near regular basis.

I would have started with checking power supply voltage and stability, powers & grounds, and start resistance testing the ECM pins per FSM. Even then the last thing the FSM will tell you is to "replace with known good component" or just replace it.

If you had an idea of what exactly the ECM is messing up (i.e. if it's messing up ignition timing and/or fuel trim/pulse width) you could probably use a DSO (Digital Storage Osciliscope) to determine if the ECM is at fault by watching the waveforms.

They want you to pay $2200 and THEY'RE NOT SURE?

I think I might go for a second opinion. And if they ask you to pay for a "diagnosis fee" I'd tell them to stuff it.

(as an aside, ECUs are cheap at wrecking yards. Maybe not "cheap", but not $2.2K either, and they rarely go south.)

I think it's a bit unfair to say "shove it" to a shop asking to be paid to perform diagnostics; just because you're asking for a "second opinion" doesn't mean the technician isn't going to start his diagnostics from scratch and spend time tracking down the problem (well he should at least, otherwise he may bite himself in the ass taking the previous diagnosis for granted). It'd be the same if you're going to see a doctor for a second opinion, they're still billing you for their time and effort.

As for the ECM I wholeheartedly agree that they don't go bad often; so I'd want to make sure the Diagnostics match that result because it's not a cheap item to replace from a "new part" standpoint. The good news is that your ECM is old enough that VIN writing isn't an issue so getting one from a junkyard might work (you'll just have to find one that matches the part number on the old ECM or is compatible, unfortunately I don't know where you get that chart.)

Sorry, no. I don't pay for a diagnosis of "maybe".

If you don't know, just tell me and I'll take it somewhere else.

Have a similar problem myself and i am waiting for my relays to be delived so i can replace them. Try replacing the EFI relay under your hood and the fuel pump relay located at the bottom of the interior fuse block. Worth a try since the parts are cheap. Could also be a fuel pump as well. Good luck.

I get that and sometimes technicians will use "that's it maybe..." as an excuse to wash their hands of a vehicle or to get more diagnostic time, that I won't deny.

But there's also the flip side of that where most shops will quote you X amount of money for the first 1hr of diagnosis. That's common shop practice in the industry because some issues cannot be resolved in 1hr, nor figured out.

I had a customer's vehicle that had an issue with their electrical system and I sank at least 2+hrs into (customer only paid for one), the best I could offer was that I managed to isolate the issue to two modules. I was pulled off the job because I already went over the 1hr allocated for the vehicle and the customer had to authorize additional time, which they refused (because the service writer did not properly explain how diagnostic time works among other issues). But because the customer refused to authorize additional time to find the issue I was left with "either one, or both of the modules and/or wiring need to be replaced" as my answer. Not to mention I took a hit to my paycheck because I actually spent longer than the allocated time on the vehicle.

I get that it's frustrating and in our industry many people take advantage of "maybe" being a excuse to wash their hands of a customer or to rake them over the coals. But also consider that if as a technician I'm being forced to work on a vehicle for 1hr of pay while being expected to put unlimited time into the vehicle, that's breaking a lot of labor laws. I mean would you work an indefinite amount of time for 1hrs worth of pay?

@Gelthos

What were the symptoms, issues you where having with your 4Runner. Also did they give you a list of DTCs and what testing methods they used to determine if the ECM was at fault?

I get that, and I feel your pain. If you put in an hour on my truck I want you to be paid for it. My point is that it would be better to send a customer down the road and for your dealership to give up an hour of billable time then to come up with a diagnosis of "throw $2K at it and maybe the problem will go away". It's the sort of thing that gives dealers a bad name even though they have the best mechanics in the biz.

"We need more time" would be a better answer, as would "It passes all of the standard tests so we don't know". I would happily pay for either of those honest responses - it's the "let's throw $2K at it" response that leaves me cold. It's just as likely to be a corroded connection or a broken wire and everyone knows that.

ecu's run a hundred bucks on ebay..prob cheaper if you look real hard. Swap it out yourself before you spend 2k! also check those relays, fuses and maybe fuel pump. Not sure if these motors are prone to ground issues....maybe check all the body grounds, ecu grounds...clean up wiring, etc.

I've owned a bunch of gen2 mr2's and this was a common issue.

And this BTW, is the mark of a real pro.

Can you get this from your dealer?

I was told it only takes 10 minute to swap out the ECU.

If that is true then I can't imagine a used (with warranty) ECU costing more than $500.

If you are near any major cities then someone at a scrapyard probably has several sitting on a shelf.

Cbr900boy has a good suggestion on the relays considering they are cheap to replace. I'm new to these engines but if there's a crank sensor, I would maybe check the connection there, make sure it's clean and not loose. Does it throw any check engine light just before it dies out? I've bought rebuilt ECUs and paid $450 for the most expensive and still got a year warranty on it, $2000 is insane

Sorry guys we were moving yesterday and I just got my internet back up. I worked for VW for many years and even though dealership rates are typically a bit higher they can usually fix it quicker, so often its a wash.

The tech that was looking at it has been a 4runner guru since 1990 so I have some confidence. I'm being told that the ecu is not communicating with the car at all.

I was driving and it shut down, I threw it in neutral and fired it back up. It did this for 3 days off and on. I thought fuel pump, fuel filter, or water in the tank so I tossed some dry gas in and it ran fine until this past snow storm when it died and would not start.

I think they just want to scare you out of your 20yr old car into a new one...

I agree with others, get a voltmeter and check their diagnosis, or go to another shop (smaller is good as they see more scenarios) for a new diagnosis (don't tell them you got one theory)

They do go bad. I just replaced mine a month ago or so because of idling issues. Cheap fix...$65 on ebay for a used ECU