Subaru Forester Owners Forum banner
Cancel

P0459 Code - thoughts on diagnosing this code

2399 Views 4 Replies 3 Participants Last post by  Bryan Lutz, 
S
Hey guys, was hoping I could get your thoughts diagnosing this code. I’ve been trying to fix my small EVAP leak and just replaced the purge control solenoid (under the hood) and am now getting a high volatage code for it.

I took my multi meter to it and found the follow:

- very small resistance between harness terminals (35 ohms I believe)

- 12 V coming from one terminal and 0V on the other with the car off

- cycling 4.5V on/off from other terminal when car is on and in test mode

- stripped the cover from the wires about 5 inches to look for shorts and didn’t find anything

- car throws a high voltage code when harness is plugged into solenoid and a low voltage code when it’s unplugged.

Am I correct assuming there is a short?

Also on a side note is it possible to just disable the EVAP codes completely? I’ve been chasing this issue for 5 months now and getting nowhere.

Thanks!

Oh and I should add that the purge solenoid does not function in test mode but will work when I bench test it.
Reply
Save
Like
1 - 5 of 5 Posts
E
resisitance

It depends on where in the circuit the voltage is measured. You most likely have a load on the ground side of the circuit. Check for a loose ground.
Reply
Save
Like
S
Would you happen to know where I can find a wiring diagram? Would help me wrap my head around this much better.
Reply
Save
Like
S
Ok so did some more troubleshooting and can't figure out why the valve isn't operating.

- I get 12V when switched to AAC on terminal 2 and when I manually ground the valve it will operate

- When the car is in test mode terminal 1 will alternate between open circuit and grounded yet the valve won't function.

Any ideas where to go from here?

Attachments

See less See more
Reply
Save
Like
B
Your problem is likely in the ECU. I have seen this many times before. A component in the ECU burns and causes this code to appear even though the wiring and EVAP valve are all good and aren't really shorted high.

There is a guy on ebay selling a kit to fix this.

They have a kit to fix the issue. I have fixed quite a few ECU's this way. Just make sure whoever installs the kit has good soldering skills.
Reply
Save
Like
1 - 5 of 5 Posts
Subaru Forester Owners Forum
We’re the best Subaru Forester Owners Forum to talk about the best years of the Subaru Forester, modifications and reliability history of the Subaru Forester.
Full Forum Listing
Explore Our Forums
General Troubleshooting and Technical Help Interior and Electronics Europe Members' Journals General Forum
Top