Hello.

 

Its been awhile since I have been here.  This is my 3rd subaru my first was a '67 Subaru wagon my second was a '?? 75 I think Legacy. And now this is a 2003 Subaru Baja 4cyl. AWD.  The CEL has been on for sometime now since I bought it.  The guy said I needed a new O2 sensor. (this has not been done)

 

Whenever it rains or has rainded and it is very humid or wet weather the car will start upon first start on my way to work .. I then drive about 15 miles and stop to get coffee .. Then when I go to leave the car simply turns over but will not start.  If I leave the car for awhile (8 hours since I walk the rest of the way to work) and then return.  The car starts fine. 

 

I took it to a guy today to read the codes for me and he gave me these numbers:

 

P0420

P0340

P0420

 

However this was a few days AFTER I have had trouble in the rain .. It only happens when it rains or is humid or very wet out It will start in the morning and let me drive it just fine.  But if I shutoff the engine and go back to it a few minutes later.. The car simply turns over until It sounds like I am going to kill my battery then I walk away and walk to work. ... not the best solution at least im not far from work (aobut 3 blocks).  not that that matters.

 

Any help appreciated.

The 420 code has to do with the catalyst. This alone won't cause your starting issue.

 

The 340 is for the camshaft position sensor. Bank one I think which is passenger side on subarus.

 

This will cause a hard start condition. Check wiring and grounds and if all is good, change the sensor.

P0420 is a bane for everyone but, it often is not the cat conv. - look for exhaust leaks, catch-up on any tune-up type stuff. Also check for corroded ground connections or rodent-chewed wiring.

Only one cam sensor. Drivers side behind the timing cover kinda below the oil fill tube.

 

That's the cause of your no-start. Either poor connection (maybe not plugged in all the way) or the wiring to the sensor is damaged and is shorting when it gets wet. Not often will those sensors fail so check wiring and the connector for corrosion/damage before replacing the sensor.