I've been chasing a P2A00 (bank 1 sensor 1 out of range) code on and off for awhile now. I had a P0141 (Bank 1 Sensor 2 heater circuit) for a year or so and then that went away and I and was replaced by the P2A00 code. In the past I've been able to clear the code before I go to smog and pass, but lately it seems that everyone has upgraded to new machines that can see this so I can longer pass (in Cali). Tailpipe emissions are all fine, it's just the damn code.

I've took it to my mechanic and asked him to replace the passenger pre-cat sensor. That was done and the code came back after the ECU emissions tests ran again (the code comes back when only "catalyst" remains "incomplete"). Went back to my mechanic and he checked for exhaust leaks, intake leaks and MAF sensor issues all of which look fine.

He cleared the code again and sent me off with a bottle of injector cleaner to run through the tank. Did that and the code came back again. Since then I've been watching the sensor output graphs through my OBD II reader (+ torque app) and I am hoping someone can help me interpret them to narrow my issue down. My mechanic wants to replace the injectors next, but that is pricey and he is just guessing at this point.

So here are some screenshots from torque.




Pic 1 - B1S1 is showing about half the voltage of B2S1 which seems to be causing the error code. B1S2 showing flatline which happens quite a bit.







Pic 2 - B1S1 showing half the voltage of B2S1 again. B1S2 is very jumpy which it seemed to do whenever it wasn't flatlined.





Pic 3 - At lunch today I cleared the mixture ratio learning. This bumped B1S1 up from 2.5 to about 3.5, but still probably not enough. Both post-cat sensors are very flat (still calibrating?)


The options I am seeing are:

• replace the bank 1 cat (maybe burned out due to leaving the codes running so long?)
• replace the bank 1 sensor 2 (maybe malfunctioning all along and is now influencing B1S1?)
• replace fuel injectors ($$$)
• bring it to the dealer ($$$, haven't had good experiences with them)

One other thing I saw on the forums was to check the spark plug coil packs as misfiring caused by these can throw this code. Do the graphs from torque look like misfiring could be happening? It appears that the code is being caused by the B1S1 voltage being pretty consistently about half of what it needs to be.

Any other tests or info on torque I could be looking at?

Thanks for any input!

 

Any luck solving this? I have had my tuner check for leaks, cleaned MAF, replaced Bank 1 Senor 1 (I only am throwing P2A00), done throttle relearn procedure and SES still comes on every 100-700 miles. Mods are below. I am at a loss for what it could be at this point.

06 6MT <40,000 miles as of this post
MD 5/16 spacer
MREV2
Z-tube
Berk HFC
HKS catback exhaust
Uprev Dyno Tune after all parts installed

 

I doubt his problem will fix yours. The original posters bank1 sensor 2 should not be flatlined, it should be fluctuating all the time and he probably just needed to replace that sensor.