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?

455

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.
5,540

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 14,507 nationwide Legacy listings starting at $2,449.

ZIP:

Subaru Legacy Experts

  • #1
    Anthony_60
    Reputation
    1,270
  • #2
    Nick Eidemiller
    Reputation
    740
  • #3
    dandyoun
    Reputation
    700
View All

Related Models For Sale

Used Subaru Impreza
182 Great Deals out of 19,474 listings starting at $2,200
Used Subaru Outback
394 Great Deals out of 34,376 listings starting at $1,500
Used Subaru Forester
407 Great Deals out of 34,020 listings starting at $1,295
Used Honda Accord
1,111 Great Deals out of 61,915 listings starting at $999
Used Toyota Camry
1,040 Great Deals out of 72,498 listings starting at $295
Used Honda Civic
818 Great Deals out of 73,280 listings starting at $1,400
Used Honda CR-V
813 Great Deals out of 54,678 listings starting at $1,750
Used Toyota Corolla
919 Great Deals out of 57,563 listings starting at $1,488
Used Nissan Altima
1,030 Great Deals out of 75,527 listings starting at $1,627
Used BMW 3 Series
1,161 Great Deals out of 33,172 listings starting at $1,000

Used Cars For Sale

2018 Subaru Legacy For Sale
6,573 listings starting at $20,405
2017 Subaru Legacy For Sale
26 Great Deals out of 2,580 listings starting at $16,665
2016 Subaru Legacy For Sale
28 Great Deals out of 663 listings starting at $13,500
2015 Subaru Legacy For Sale
61 Great Deals out of 1,350 listings starting at $9,990
2014 Subaru Legacy For Sale
25 Great Deals out of 718 listings starting at $9,750

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.