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.
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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?
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!
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!
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.