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Jared D
Jared D, ASE Certified Technician
Category: Subaru
Satisfied Customers: 1782
Experience:  Shop Supervisor at County Fleet
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Have a 2004 forester. The check engine light came on a while

Customer Question

Have a 2004 forester. The check engine light came on a while back. Got the codes out of it. P0456,P0457, P0483, and P1443 , also Cyl 2 misfire. I know that the vehicle had been hit (rear ended) a while back. Have to leave it run when you fill with gas or it runs rough for a little while. Any ideas (presume it has to do with the EVAP system)?
Submitted: 1 year ago.
Category: Subaru
Expert:  Jared D replied 1 year ago.

Let's look at each of those codes:

p0457- Probably causing your fueling issue- the canister drain cut valve is probably stuck and not allowing fuel vapors to escape, essentially causing a rich condition if you don't leave it running while driving.

Expert:  Jared D replied 1 year ago.

P0483- This code indicates an engine overheating issue. This usually means the thermostat is not operating correctly. Check the following:

1. Check cooling fan operation for both temperature (around 220 degrees) and A/C operation (they should turn on when the ac is turned on).

2. Check radiator airflow, sand or debris obstructing airflow.

3. Check coolant strength. Mixtures stronger than 50/50 can set this code.

Expert:  Jared D replied 1 year ago.

P1443- This could also be causing the fuel issue- It indicates that the purge control valve is not activating correctly. To test it:

1. Using a voltmeter, check for 12 V on the Yellow/Green wire at the drain valve.

2. Check for restriction in the hoses going to the canister and from the canister. Verify that the canister is not clogged.

3. Using the green test connectors underneath the dash on the driver side, plug the connectors in together, turn the ignition switch on, the Check Engine Light will start to flash and solenoids will start to click. Check the drain valve operation from the computer, blow through the drain valve using your mouth, check to see if the solenoid will hold and release each time it clicks.

4. If it constantly holds and does not release, the solenoid valve is weak.

Expert:  Jared D replied 1 year ago.

P0456-- is defined as EVAP system small leak (less than a 0.020"). Use a calibrated smoke checker. Close the system by energizing the canister drain valve, then smoke check/test the EVAP system.

Use a vacuum pump to pull a small (1 inHg) vacuum on the purge solenoid from the canister side to see if it will hold a vacuum.

Expert:  Jared D replied 1 year ago.

Since most of these codes are related (except for the p0483) I would probably check for a damaged evap canister assembly, torn/cracked evap lines, or a damaged charcoal canister. Do you plan to replace these parts yourself?

Expert:  Jared D replied 1 year ago.

Please let me know if you need any additional information. Don't forget to rate (that's how we experts get paid).