Engine replaced, CEL still gives same codes

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Hi there,

I had a CEL misfire on cyl 3 and potential rod knock on my EJ253 engine in my 2010 Subaru Impreza.

I recently replaced my engine with another EJ253 engine I got at PMPauto in PA. The donor engine was from a 2008 Subaru Legacy. I had to swap over my old intake, exhaust, fuel injectors, spark plugs, and coil pack. I also replaced my trans cooler lines because the old one had a leak. The car also has a new radiator and starter.

After replacing the trans cooler lines, the car starts with no signs of leaks. I took it for a test drive and everything was good. I took it for a test drive an hour ago and the CEL, cruise control and traction control lights all turned on.

I come back home and plug in my code reader. According to the code reader it’s throwing the same codes as my old engine did including the misfire on cyl 3. The engine was leakdown tested and compression tested, and head gaskets replaced by MLS head gaskets, before buying it.

I will say I purchased a used ECU and transferred the chip from the old ECU to the new ECU. The chip holds all of the information about the car and I am guessing it’s memory. So basically I had a company clone my ECU.

Does anyone know if it’s possible that the car is running fine and the ECU is throwing false codes from the previous engine?

Will Resetting the ECU get rid of these false codes?

I can’t erase some of these codes from my code reader because they are permanent codes.

Any and all help would be greatly appreciated!!! Please help!
 
Sucks that no one here could give any advice. Did you ever get anywhere on this issue? What did you learn?
 
Hi there,

I had a CEL misfire on cyl 3 and potential rod knock on my EJ253 engine in my 2010 Subaru Impreza.

I recently replaced my engine with another EJ253 engine I got at PMPauto in PA. The donor engine was from a 2008 Subaru Legacy. I had to swap over my old intake, exhaust, fuel injectors, spark plugs, and coil pack. I also replaced my trans cooler lines because the old one had a leak. The car also has a new radiator and starter.

After replacing the trans cooler lines, the car starts with no signs of leaks. I took it for a test drive and everything was good. I took it for a test drive an hour ago and the CEL, cruise control and traction control lights all turned on.

I come back home and plug in my code reader. According to the code reader it’s throwing the same codes as my old engine did including the misfire on cyl 3. The engine was leakdown tested and compression tested, and head gaskets replaced by MLS head gaskets, before buying it.

I will say I purchased a used ECU and transferred the chip from the old ECU to the new ECU. The chip holds all of the information about the car and I am guessing it’s memory. So basically I had a company clone my ECU.

Does anyone know if it’s possible that the car is running fine and the ECU is throwing false codes from the previous engine?

Will Resetting the ECU get rid of these false codes?

I can’t erase some of these codes from my code reader because they are permanent codes.

Any and all help would be greatly appreciated!!! Please help!

Did you get it going? Also what were the other codes it was throwing if any?
 

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