2015 Legacy 2.5 - Intermittent flooding and smoking

[kiellish]

Hello all, I have a 2015 Legacy 2.5 that has some strange issues.

Codes

p0102 - maf low circuit
p0327 - knock sensor low circuit
p2103 - throttle actuator control circuit high
p0203 - injector circuit malfunction #3

They consistently come back, but don't always trigger a check engine light even though they are showing on the scanner. Sometimes runs fine, other times floods badly, runs on three cylinders and smokes like crazy.

Replaced the injector on cylinder 3, same issue. Swapped injectors around and same issue w/same codes. It floods sometimes to the point where it fills cylinder 3 with gasoline and locks the engine. Injectors, spark plugs, coils, wiring, connectors, grounds all look fine. ECM circuit board looks fine (as in burn spots or broken solder connections). Cleaned a few grounds to no avail.

Haven't tested the injector connectors with a noid light but I think it would be sort of pointless, especially given the intermittent nature of the problem. I think it is probably a bad ECM or a wiring issue.

Does anyone have any experience with something similar? Are there any decent wiring diagrams for the engine harness? I haven't been able to find anything.

One last thing - does the ECM require programming? There are a bunch on ebay for $25, was thinking of swapping out just to try.

Any help is appreciated!

 

[kiellish]

Hello all, I have a 2015 Legacy 2.5 that has some strange issues.

Codes

p0102 - maf low circuit
p0327 - knock sensor low circuit
p2103 - throttle actuator control circuit high
p0203 - injector circuit malfunction #3

They consistently come back, but don't always trigger a check engine light even though they are showing on the scanner. Sometimes runs fine, other times floods badly, runs on three cylinders and smokes like crazy.

Replaced the injector on cylinder 3, same issue. Swapped injectors around and same issue w/same codes. It floods sometimes to the point where it fills cylinder 3 with gasoline and locks the engine. Injectors, spark plugs, coils, wiring, connectors, grounds all look fine. ECM circuit board looks fine (as in burn spots or broken solder connections). Cleaned a few grounds to no avail.

Haven't tested the injector connectors with a noid light but I think it would be sort of pointless, especially given the intermittent nature of the problem. I think it is probably a bad ECM or a wiring issue.

Does anyone have any experience with something similar? Are there any decent wiring diagrams for the engine harness? I haven't been able to find anything.

One last thing - does the ECM require programming? There are a bunch on ebay for $25, was thinking of swapping out just to try.

Any help is appreciated!

Update:

After testing continuity for the injector wiring between the ecm connector and injector connector, irregularities were apparent, especially when flexing the wiring harness. The problem was the purple wire to injector #3. Repaired broken portion and seems to have corrected the problem. Maybe this can help someone in the future.

The damaged portion was in an area not covered by the plastic wire loom, so it makes sense that it was more likely to be damaged.