Has anyone ever replaced their ECM? How often do they fail? Is it likely to fail and have zero codes generated, or visversa, tons of codes all over.

 

Turn the key to on, if your cel is there then the ECM is alive. If not start looking for a new one.

 

Why start looking for a new one?

 

If the cel isn't on with the ign in on wouldn't that indicate the ECM is dead?

 

Yeah, maybe... if you're sure the ignition switch is working too.

 

In 25 years of working on Toyota's I've never heard of an ECM failing all by itself. It usually takes an electrical mistake by someone that causes it to fry.

The CEL will be inop if the EFI relay has failed. Or the bulb is burned out. Or a wiring issue. The FSM has a trouble shooting section on the ECM that will take you through tests to determine what the problem is. Go through that before replacing an expensive ECM.

 

ECU failures have occurred but they're VERY infrequent. I'd check for other issues first.

 

Thanks, I think I found other issues (inline fuel filter). Thanks all for the posts. I dont believe I am looking at ECU failure.

 

I have had 2 ECU's with holes rotted in the sides of them and full of salt and water. They work fine. The ECU's in these trucks are very dumb and do not have much in them. Like was said, human error blowing them (still hard to do as most of it is protected with the efi fuse) or 1 in 10 million component failure.