Hi,
I bought a ODB2 code reader and the Torque Android App and it says Error Code P0420- Catalyst System Efficiency Below Threshold (Bank 1). I need help figuring out which Oxygen sensor (hopefully not the cat) to replace. There is no problem with idling but I've noticed a 2 mpg drop in gas mileage. Here are test results:
Test report:
------------------
TID:$03 CID:$01
- Low sensor Voltage for switch time calculation
Min: 150
Test result value: 861
PASS
----
TID:$62 CID:$04
-
Max: 4,448
Test result value: 4,979
FAIL
----
TID:$64 CID:$04
-
Max: 4,064
Test result value: 79
PASS
----
TID:$79 CID:$01
-
Max: 34,306
Test result value: 32,757
PASS
----
TID:$7a CID:$01
-
Max: 34,306
Test result value: 32,760
PASS
----

 

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I can't move your thread because you never said what car you have, so I am closing the thread and will delete it when I see you have reposted it in the forum applicable to your car.