Just before I went for my PA state inspection, my CEL came on.

 

I pulled three codes from it: PO133, P0420 and P1442.

 

The car's a 2002 Outback Sport with 141,000 miles on it. I had the cat replaced under warranty in the 85,000 mile range. From reading other posts, I know that the 133 and 420 indicate the front and rear 02 sensor failure. I am suprised they'd go bad at once though. Anything else it could be?

 

I have NO idea where the 1442 fits into this whole thing.

 

I have a terribly low budget at this point so any help I could get before throwing parts at this situation would be helpful.

[quote name='mattoh130']Just before I went for my PA state inspection, my CEL came on.

I pulled three codes from it: PO133, P0420 and P1442.[...][/quote]The first two codes could easily be caused by a bad front O2 sensor alone.


[quote]I have NO idea where the 1442 fits into this whole thing.[...][/quote]Some info I have for P1442 says "Fuel Level Sensor Circuit Range/Perf", another says "Fuel Tank Pressure System Range /Performance No. 2". That appears to be an EVAP system code.

Does your fuel gauge indicate accurately? Did you recently refill the gas tank? Did you possibly overfill it, or leave the cap loose? Any other clues as to recent occurances that might be related?

Hi. Closest manual I have is for '00obw.

 

DTC P0133 - FRONT OXYGEN (A/F) SENSOR CIRCUIT SLOW RESPONSE

DTC DETECTING CONDITION: Two consecutive driving cycles with fault

Loose installation of front portion of exhaust pipe onto cylinder heads

Loose connection between front exhaust pipe and front catalytic converter

Damage of exhaust pipe resulting in a hole

CHECK: Is there a fault in exhaust system?

YES: Repair exhaust system.

NO: Replace front oxygen (A/F) sensor. (Note by porc: OEM sensor is highly suggested, not aftermarket)

 

The front o2 could also be causing your P0420, catalyst efficiency below threshold (could also be exhaust leak causing both).

 

 

P1442 is an emissions code; the ECU doesn't know when to perform the fuel system integrity/pressure test without this signal.

 

DTC P1442 - FUEL LEVEL SENSOR CIRCUIT RANGE/PERFORMANCE PROBLEM 2

 

DTC DETECTING CONDITION: Two consecutive driving cycles with fault

CAUTION: After repair or replacement of faulty parts, conduct CLEAR MEMORY MODE and INSPECTION MODE. Refer to How To Clear Diagnostic Trouble Codes.

 

11CJ1: CHECK ANY OTHER DTC ON DISPLAY

CHECK: Does the Subaru Select Monitor or OBD-II general scan tool indicate DTC P0461, P0462 or P0463?

YES: Inspect DTC P0461, P0462 or P0463 using "11. Diagnostics Chart with Trouble Code for AT Vehicles".

NOTE: In this case it is not necessary to inspect this trouble.

NO: Replace fuel level sensor and fuel sub level sensor.

Another question: Was there any off-roading, or other situation where the bottom of the car could have hit something? (I'm thinking possible damage to the exhaust system and gas tank.)

Interesting...

 

The gas cap is secure and the fuel indicator is reading what I believe to be the correct amount. I haven't done any off-roading with the vehicle either and it hasn't bottomed-out during driving.

 

I'll have to check for exhaust leaks. If there are no leaks, are you saying that a bad primary 02 sensor could throw P0133 AND P0420?

[...]If there are no leaks, are you saying that a bad primary 02 sensor could throw P0133 AND P0420?

Yes. In fact, the diagnostic procedure for P0420 says that if certain other codes (P0133 among them) are also present, it isn't necessary to proceed with diagnosing the P0420. As long as you're sure there are no exhaust leaks, P0133 normally indicates a bad front O2 sensor.

 

However, while you're checking for exhaust leaks, look over any electrical connectors down there, and see if any of the ground connections seem corroded. (I'm wondering why the P1442 and the O2 sensor-related codes showed up simultaneously, and an electrical problem might explain that. Of course, it could just be coincidence...)