Subaru Forester Owners Forum banner

P0302 when it's raining, right after starting.

1482 Views 2 Replies 3 Participants Last post by  Billgiblet
When its damp and rainy, forester sometimes throws a P0302 code. This is right after I start the car cold. I always let the car warm up, meaning I wait until after the blue temperature light on the dash goes out, before I start driving. The Forester feels like its hesitating, and if I apply gas to rev up the engine, the CEL turns off.

I had the 120K tune-up done within the last 12 months, or 8K miles. I saw a past thread mentioning coil pack wires or spark plug wires?
1 - 3 of 3 Posts
High humidity and cold air potentially causes moisture to condensate on ignition wires. Seen this happen all the time when I used to live in Vancouver, BC. This condensation would then cause either a no start condition or miss-fire.

Personally I never warm up the Subaru warming up really is a waste of fuel and does not help "warm" everything up at the same time. Just start it and go, usually within 1/2 mile to 1 mile the engine coolant is already approaching 60 C. Sitting their letting it idle for 20-30 mins, you'd be lucky if it even comes close to 60C, it might stay around 40C. While you're sitting their letting it idle, that transmission is not warming up at all. If you have good 5W-XX oil, its thin enough to lubricate the engine well enough to not warrant idling.....
  • Like
Reactions: 1
If you haven't already done it, replace your plug wires, and plugs while you're at it, if they're old. Fairly inexpensive and easy thing to do. The damp weather onset pretty much id's the problem. If that doesn't do it, maybe time for new coil.
1 - 3 of 3 Posts