OBD2 Codes...CAT, O2 Sensor, or Something Else?

Asked by Mar 22, 2012 at 10:29 PM about the 2000 Subaru Legacy L

Question type: Maintenance & Repair

I have a 2000 Subaru Legacy L Sedan.  It died while driving home.  The lights, radio, and power all work, so I don't think it's the battery or alternator.  I checked the belts, and the car has gas and oil.  I borrowed an OBD2 scanner from AutoZone and it pulled these codes: P0328, P0340, P0420, P0031, P0336 (PENDING), P0341 (PENDING), and P0340 (PENDING).  I think P0328 can be disregarded because this code has been on for years (just haven't replaced the Engine Knock Sensor).  How do I know if it's possibly the CAT or O2 sensors, or something else fuel or ignition related?  Any suggestions would be appreciated.  Thank you!

5 Answers

10

usually most P0300 codes no matter the make or model of vehicles seem to be a misfire issue? or at least that is what i have noticed...

What does that mean? Timing? Spark Plugs?

445

336 and 340/341 are crankshaft position and camshaft position sensors circuit issues, respectively. 420 could be an exhaust leak, causing the Cat sensors to misread, or just an issue caused by the other codes. The 31 code is kind of confusing, it is either an ABS issue, or if it is supposed to read 301 it is a misfire in cylinder #1. You may try to contact a dealer and see if the vehicle ever had any recalls performed, and if there are any updated reprograms for the ECM. From the sounds of it, though, there may be a computer issue for it to be throwing all of these codes at the same time. I would recommend checking your wires for loose connections, rub-throughs, corrosion, etc. Especially if you have not had any work performed recently.

10

timing belt

1 of 1 people found this helpful.
5,290

Hmmm.... Does it restart and run normally? If not, sure: I'd indeed check the t-belt, as noted above. Note that misfire codes are PO301-4. The crank/cam shaft sensor codes hint toward the t-belt, rather than wiring issues. The PO420 is just your cat getting old, bad gas, or the electrical fairies that plague Subies and Toyotas with this code. BTW, I would NOT ignore the knock sensor, as they're cheap (same as Nissan), and will contribute to smoother running, engine protection, and improved power and fuel eco. Good luck.

Your Answer

Legacy

Looking for a Used Legacy in your area?

CarGurus has 13,454 nationwide Legacy listings starting at $900.

ZIP:

Subaru Legacy Experts

  • #1
    Anthony_60
    Reputation
    1,270
  • #2
    Nick Eidemiller
    Reputation
    720
  • #3
    dandyoun
    Reputation
    700
View All

Related Models For Sale

Used Subaru Impreza
211 Great Deals out of 18,364 listings starting at $1,500
Used Subaru Outback
379 Great Deals out of 36,862 listings starting at $995
Used Subaru Forester
379 Great Deals out of 33,689 listings starting at $995
Used Honda Accord
1,019 Great Deals out of 62,741 listings starting at $999
Used Toyota Camry
1,081 Great Deals out of 72,629 listings starting at $990
Used Honda Civic
834 Great Deals out of 78,398 listings starting at $900
Used Audi A4
306 Great Deals out of 10,808 listings starting at $1,500
Used Nissan Altima
1,154 Great Deals out of 74,938 listings starting at $999
Used BMW 3 Series
1,044 Great Deals out of 31,562 listings starting at $1,000

Used Cars For Sale

2018 Subaru Legacy For Sale
3,716 listings starting at $20,405
2017 Subaru Legacy For Sale
27 Great Deals out of 4,249 listings starting at $14,478
2016 Subaru Legacy For Sale
35 Great Deals out of 686 listings starting at $12,888
2015 Subaru Legacy For Sale
37 Great Deals out of 1,246 listings starting at $9,990
2014 Subaru Legacy For Sale
38 Great Deals out of 889 listings starting at $7,995

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.