03 subaru legacy engine trouble

Asked by Mar 28, 2016 at 06:37 PM about the 2003 Subaru Legacy 2.5 L

Question type: Maintenance & Repair

2003 subaru legacy l wagon 2.5

Misfiring, backfiring, loss of power, engine vibration, stalling, now wont move. I have po301,
302, 420, and 457 codes.

Replaced plugs, wires, fuel filter, upstream o2 sensor, and crank sensor. Im out of ideas and
money. I need to know what this issue is soon or I may just drive the thing off a cliff and never
look back. at my wits end. Please help.

2 Answers

76,335

The po302 was a miss fire on cylinder #2, P0420 SUBARU - Catalyst System Efficiency Below Threshold... Possible causes... - Three way catalyst converter Bank 1 - Exhaust tube - Intake air leaks - Fuel injectors may be faulty - Fuel injector leaks - Spark plugs may be faulty - Improper ignition timing - Engine Control Module (ECM)... Some Tech notes.... As the code description implies the P0420 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic convert needs to be replaced to fix the problem. If the P0420 code is combined with other codes, try fixing the other codes first.... P0457 SUBARU - EVAP System Leak Detected Fuel Cap Loose/Off... Possible causes.... - Missing fuel filler cap - Incorrect fuel filler cap used - Fuel filler cap remains open or fails to close - Foreign matter caught in fuel filler cap... EVAP control system has a very large leak such as fuel filler cap fell off Possible symptoms... - Engine Light ON (or Service Engine Soon Warning Light) - Possible a noticeable fuel odor caused by the release of fuel vapors.... P0457 Subaru Description.... This diagnosis detects leaks in the Evaporative Emission System (EVAP) purge line using engine intake manifold vacuum. If pressure does not increase, the Engine Control Module (ECM) will check for leaks in the line between the fuel tank and EVAP canister purge volume control solenoid valve under the following vacuum test condition... The vacuum cut valve bypass valve is opened to clear the line between the fuel tank and the EVAP canister purge volume control solenoid valve. The EVAP canister vent control valve will then be closed to shut the EVAP purge line off. The EVAP canister purge volume control solenoid valve is opened to depressurize the EVAP purge line using intake manifold vacuum. After this depressurization is implemented, the EVAP canister purge volume control solenoid valve will be closed.

6,170

You need an ignition coil. $40 on eBay. Keep it simple.

1 of 1 people found this helpful.

Your Answer

Subaru Legacy Experts

  • #1
    Anthony_60
    Reputation
    1,270
  • #2
    Nick Eidemiller
    Reputation
    740
  • #3
    dandyoun
    Reputation
    730
View All

Related Models For Sale

Used Subaru Impreza
202 Great Deals out of 22,981 listings starting at $1,505
Used Subaru Outback
434 Great Deals out of 36,930 listings starting at $1,000
Used Subaru Forester
403 Great Deals out of 39,151 listings starting at $1,000
Used Subaru Impreza WRX
42 Great Deals out of 1,172 listings starting at $1,500
Used Honda Accord
1,116 Great Deals out of 74,393 listings starting at $1,100
Used Toyota Camry
1,106 Great Deals out of 87,564 listings starting at $995
Used Honda Civic
832 Great Deals out of 61,320 listings starting at $950
Used Subaru Impreza WRX STI
27 Great Deals out of 628 listings starting at $9,490
Used Nissan Altima
1,222 Great Deals out of 77,845 listings starting at $1,695
Used BMW 3 Series
1,170 Great Deals out of 33,026 listings starting at $1,200
Used Audi A4
321 Great Deals out of 12,648 listings starting at $1,899
Used Toyota RAV4
812 Great Deals out of 54,149 listings starting at $1,600

Used Cars For Sale

2018 Subaru Legacy For Sale
8,502 listings starting at $19,672
2017 Subaru Legacy For Sale
30 Great Deals out of 1,478 listings starting at $15,000
2016 Subaru Legacy For Sale
23 Great Deals out of 658 listings starting at $11,495
2015 Subaru Legacy For Sale
87 Great Deals out of 1,588 listings starting at $10,950
2014 Subaru Legacy For Sale
27 Great Deals out of 583 listings starting at $6,999

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.