What is your question?
·
·
What is your question?
My Quest ECM burned out. I want to find out what could have caused it so that it doesn't happen again. I have checked all the grounds I can find. Chasing a voltage surge is VERY time consuming. Anyone have any suggestions where to start? New alternator 1 1/2 years ago. New battery 6 mos ago. Distributor too. Got P0300 prior to ECM failure, rough running, rough idle, hesitation. Was looking for a vacuum leak when the van died. checked the ECM, it was burned. Vacuum leak couldn't have caused it. Guessing a voltage surge or short, but I haven't the foggiest where to start looking. edit- the issue turned out to be a short to ground in the injector circuit, overloading the ecm and burning it completely. testing continuity from the battery side and disconnecting junctions showed the location eventually.
1 Reply
What do you mean by "burned out"? It would be highly unusual for a PCM / ECM to be damaged as you are suggesting. Also, if you're getting a diagnostic trouble code, what is faulty about your ECM?
Im seeing burn components inside the ECM. Wish i could post a pic. Something overloaded inside it and burned out. As far as I understand it, only a short or overload would cause this kind of damage. I just need to figure out where the short/overload came from. As far as the testing, I figured as much. I can't tell what circuit is burned out, so it becomes harder to nail down which circuit overloaded/shorted.
I know this is years later but if I can help someone else with the same issue great. it turned out to be a short to ground on the injector circuit. it was causing an overload in the ecm and physically burning the components out. i mean magic smoke being released. I bypassed the circuit and then narrowed it down by continuity testing and disconnecting relays until it was found.
There is a component inside the ECM that is cracked and fried. I was driving and the van died accompanied by a strong ozone smell from the glove box. This led me to examine the ECM. Not sure what circuit the component controls but the van won't turn over now. Originally I was just hunting the P0300. I wasn't expecting the ECM to fail. That's why I want to find out what fried it, so that it doesn't happen again.
Perhaps I gave the wrong impression. I wasn't even considering the ECM as a problem regarding the p0300. This was just the cherry on top of the mess I had already. I guess what I'm wondering is if the reason for the P0300 is linked to the ECM failure, or if it's just coincidence. Is there a short somewhere that was causing the P0300 or was the ECM failing? Did a short cause the ECM failure too? These are things I don't know yet. Im looking for someone to point a direction I should look to find what caused the ECM failure. The P0300 I can continue to work on once I get the van running.
So, you're seeing physically burnt terminals externally? I'm not understanding how you can suggest it's burned unless a diagnostic tool is not communicating or there is physical evidence. As far as a direction to determine the failure -- it's simply impossible without hands on testing. You'll need to see what components are not communicating and then test from there. There's nothing anyone can suggest remotely. I'm sorry!