My daughter called me up and says her check engine light is on and can "dad look at it for her". Of course, I said yes.

 

2001 Forester, 5-speed manual, 138,000 miles. Car runs fine, according to her, and it seemed to be running fine when I looked at it.

 

P0328 - Knock Sensor 1 Circuit High Bank or Single Sensor

 

P0451 - Evaporative Emissions System Pressure Sensor

 

P0442 - Evaporative Emissions System Leak Detected

 

The research I've done shows the P0328 is probably a bad knock sensor. Where do I start looking for the other (2) items? Her car is due for State Inspection & Emissions testing this month and they will not pass the car here in PA with the check engine light on. Thoughts? Thanks!!

 

None of these will cause further damage or leave the car stranded/no start condition, etc. Rarely a knock sensor can get bad enough that the car does drive poorly because it retards the timing - but that usually takes awhile and they're still drivable.

 

1.  yep, knock sensor needs replaced.  they're like $15 on ebay and easily replaced - takes 20 minutes.

 

the other two i'm less familiar with - probably just a leaky hose or rusty fitting/line somewhere. 

 

the fuel filler hoses often rust behind the passengers side rear wheel well.  i think your car has an evaporative emissions electrical component back there.  if so and it's monitored by the ECU at all - that would be a likely culprit.  i've replaced a few of those fuel filler hoses and solenoids. this is probably very likely.

 

 

the best approach is to clear the codes and see which one comes back first, it's not uncommon for one code to "cause" others.

Thanks. I'll do the knock sensor and see where things are after that. I did the knock sensor on the wife's 1999 Forester not (3) weeks ago, as well.

nice hit.  the 01 forester and 99 forester are the exact same engine so it'll be the same process to replace.

That's good news. Thanks!