iben Posted May 1, 2013 Share Posted May 1, 2013 I have a 3L Outback and it keeps throughing up the code P0420- testing the car whilst driving with the ECM being monitored this came up from a test. All the parameters pass with the exception of the first one. At the moment the Bank 1 Sensor 2 hasnt brought the engine light back on, but I know it will do. Can anyone give advice as to what the FAIL is, and its causes. Many thanks in advance Test report:------------------TID:$01 CID:$01- Rich to Lean sensor threshold voltage(constant)Max: 5,805Test result value: 7,219FAIL----TID:$02 CID:$01- Lean to Rich sensor threshold voltage(constant)Min: 8,483Test result value: 16,392PASS----TID:$02 CID:$02- Lean to Rich sensor threshold voltage(constant)Max: 65,535Test result value: 16,392PASS----TID:$05 CID:$01- Rich to Lean sensor switch time(calculated)Max: 2,720Test result value: 631PASS----TID:$06 CID:$01- Lean to Rich sensor switch time(calculated)Min: 100Test result value: 161PASS----TID:$06 CID:$02- Lean to Rich sensor switch time(calculated)Max: 51Test result value: 9PASS----TID:$08 CID:$01- Maximum sensor Voltage for test cycle(calculated)Max: 2,720Test result value: 858PASS----TID:$01 CID:$01- Rich to Lean sensor threshold voltage(constant)Max: 5,805Test result value: 7,219FAIL----TID:$02 CID:$01- Lean to Rich sensor threshold voltage(constant)Min: 8,483Test result value: 16,392PASS----TID:$02 CID:$02- Lean to Rich sensor threshold voltage(constant)Max: 65,535Test result value: 16,392PASS----TID:$05 CID:$01- Rich to Lean sensor switch time(calculated)Max: 2,720Test result value: 631PASS----TID:$06 CID:$01- Lean to Rich sensor switch time(calculated)Min: 100Test result value: 161PASS----TID:$06 CID:$02- Lean to Rich sensor switch time(calculated)Max: 51Test result value: 9PASS----TID:$08 CID:$01- Maximum sensor Voltage for test cycle(calculated)Max: 2,720Test result value: 858PASS---- End of report. Quote Link to comment Share on other sites More sharing options...
Gambit Posted May 1, 2013 Share Posted May 1, 2013 Hope this helps P0420 Catalyst System Efficiency Below Threshold (Bank1) Full list posted here :) http://uk.subaruownersclub.com/forums/topic/217-obd-codes/ Quote Link to comment Share on other sites More sharing options...
iben Posted May 1, 2013 Author Share Posted May 1, 2013 Hi Gambit Thanks for the reply. I have a obd2 BT reader that connects to my smartphone so I know the code and I can also reset it. Whilst driving the car once I'd reset the fault code this fault on the rich to lean sensor came up, but the O2 sensor hasn't yet. This may be what is causing the P0420 code so I was looking for advice on the rich to lean sensor. The rich to lean isn't putting up any warnings on the dashboard. Quote Link to comment Share on other sites More sharing options...
Gambit Posted May 1, 2013 Share Posted May 1, 2013 Oh ok ;) have you done any mods at all upgraded any parts to the car. Quote Link to comment Share on other sites More sharing options...
iben Posted May 5, 2013 Author Share Posted May 5, 2013 Hi Gambit, that's for your reply and my apologies for my late reply. I haven't had the car long but as far as I know its hasn't been modified. It goes well enough and is returning 27mpg so I'm hoping its nothing too expensive. My brother in law is a mechanic so he's going to get it in his work shop and we'll get a diagnostic computer on the thing and see if we can't trace the fault. I know its reading P0420 and seems to be running rich to lean, but whether the rear 02 sensor is causing the rich to lean or the rich to lean is throwing up the O2 sensor yet needs to be determined. Its just annoying that it knocks out the anti skid and the cruise control. Its a lovely car although, I'm enjoying driving it regardless of the dreaded dashboard lights. Quote Link to comment Share on other sites More sharing options...
Gambit Posted May 5, 2013 Share Posted May 5, 2013 No problem mate I'm always here waiting for reply's :) I have no life ;) As for the lights just put your music on loud and have a personal moving disco ;) I would go with the 02 sensor being the fault also but that is a guess. here is a list that will give you the code Leaded fuel was used where unleaded was called for A damaged or failed oxygen sensor (HO2S) Downstream oxygen sensor (HO2S) wiring damaged or connected improperly The engine coolant temperature sensor is not working properly Damaged or leaking exhaust manifold / catalytic converter / muffler / exhaust pipe Retarded spark timing The oxygen sensors in front and behind the converter are reporting too similar of readings Leaking fuel injector or high fuel pressure Cylinder misfire Oil contamination And some thing's to try. But best bet if your brother in law is a mechanic and has a good diagnostic computer might pin point it better. Check for exhaust leaks at the manifold, pipes, catalytic converter. Repair as required. Use a scope to diagnose the oxygen sensor operation (Tip: The oxygen sensor in front of the catalytic converter normally has a fluctuating waveform. The waveform of the sensor behind the converter should be more steady). Inspect the downstream heated oxygen sensor (HO2S), replace if necessary Replace the catalytic converter 1 Quote Link to comment Share on other sites More sharing options...
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