Troubleshooting a P0420 CEL on a 2002 manual.
I'm doing what I can before I just give in and install a spacer on the second O2 sensor. I'm in CA and anxious about someone noticing it during smog visual inspection.
I've done some general maintenance and some why-not/wishful-thinking work (oil change, new air filter, upgraded engine grounds, Cataclean gas additive) but to no apparent benefit. The only previous work I've done on the exhaust/cat is that I've added some straps and some clamps to reduce rattling noises.
Anyhow, I've been using the Torque app to monitor the sensors, and I have two questions.
1) Torque has a "Test Results" feature that returns a bunch of results that seem more specific than the P0420 code. In particular, I get:
TID: $05 CID:$01
Rich to Lean sensor switch time(calculated)
Where is this coming from, and is it telling me anything more specific than just the P0420 code?
2) The three O2 sensors are labeled 1x1, 1x2, and 1x3. Does the numeric order correspond with the order in the exhaust system? (1x1 is first, 1x3 is last)? Doing some short drives I see a trend that the first sensor returns about 0.6-.0.7 volts, the second sensor returns around 0.8-0.9 volts, and the third sensor returns around 0.9 volts, and occasionally spikes up to 1.3.
I interpret higher numbers as being "worse". Is this broadly correct? If so, what explains this increasing trend? And are there any signs that I should be considering replacing sensors? (would rather not waste the money if it's unlikely to improve anything)
Any advice is appreciated. Thanks!