Engine codes p1507 and p0365

[alfie]

Hey everyone, I'm after a bit of insight on these engine codes, p1507 - idle control system malfunction and p0365 - camshaft position sensor B (bank 1). I imagine p1507 is due to the engine going into fail safe mode in response to p0365 but correct me if I'm wrong.

 

This is on a JDM 2002 GGA WRX (non STI).

 

Engine starts and idles fine until up to temperature. When it gets to temp and idle speed drops the check engine light comes on and it begins to surge at idle and runs rough if revs are increased from idle.

 

I have found conflicting information regarding the number of camshaft position sensors but as far as I can tell there is likely just one on my engine below the oil filler cap. This one tests at around 2kohm which supposedly suggests it is fine. Is there one below the turbo on non STI models? Is this one visible without removing anything if it is on this model or can I only tell once I get some bits off?

 

I have also found a suggestion that the timing belt could cause this as it can slacken a bit at low revs when worn out.

 

Any help or anything else that you think could be helpful is much appreciated.

 

Cheers

Edited October 4, 2022 by alfie

[boon]

Is it AVCS?

 

Wonder if this is one of the "oil in the ECU" (yes, I am 100% serious) ones.

 

I'm about 95% sure these engines have two (at least two?) camshaft position sensors, I think one does cam position and the other two do cam advance if it has AVCS. These are at the rear of the motor, on top of the head.

 

I'd start by unplugging the big engine loom connector on each side and see if it has oil in it. If it does, clean it out, then pull your ECU and see if the connector for that has oil in it.

Long story short, if it's AVCS, the seals on one of the sensors fail and it pushes oil up into the loom. Because the loom is actually surprisingly well sealed, over quite a long time (like... 20 years) oil can work its way all the way up to the ECU and cause all sorts of weird issues.

 

I think if yours was a genuine IACV fault, which is pretty rare on anything post-2000-ish, it wouldn't idle at all.

[alfie]

Yeah it's AVCS. I'll have a look in the next couple of days and check for oil and have dig around to get to the sensors.

 

Cheers boon.

[alfie]

Just an update. 

 

Boon was right. Oil had made its way into the loom plug behind the airbox. No signs of it making it any further. Cleaned it out and the problem is gone.

 

P1507 was caused by the iacv being stuck. Soaked it in CRC and loosened it up. After a running it a few times it appears to have freed up and idle is back to normal after a good run.