P2A00 - A/F Sensor Circuit Range/Performance (bank 1 sensor 1)
 

I know this is not technically a FI problem but I'm opening it here because I am only looking for FI based feedback on the code.

What's happened:
- In early July the referenced code was thrown. The car had ~46k miles on it so I figured it was probably a bad O2 and ordered the new part. Deleted the code and babied it back and forth to work until the sensor came in. I would say I put between 150-200 miles on the car after I cleared the code.
- Receive the new sensor and replaced it.
- Drove for 400-500 miles and the code came back yesterday. (so roughly 600 miles between codes and a new sensor)

How it runs:
- Car runs exactly as it always has since my tune (roughly 2000 miles). Idles fine, closed loop and open loop acting as normal.

What I've checked:
- Sensor plug is firmly seated into its socket
- Wiring was good when I put it in and I covered it with a Thermo-tec sleeve to make sure heat was not an issue (it is the O2 sensor that basically sits less than a foot from the cold side of the turbo). I can't see there being any melting issues on the harness. Item to note I had not wrapped the original sensor when I did the turbo install and when I removed it the wiring for the sensor still looked perfect.
- Checked all silicon couplers on the intake piping, no leaks I can see
- Checked half the triangle flange on the header, can't currently see the other half without dropping the turbo. Don't see any areas where I think the gasket has blown out.
- I monitor fuel pressure all the time and it's steady, no drops or erratic behavior
- Innovate shows both closed and open loop AFRs are unchanged
- I did not have time to log idle and closed loop AFRs from UpRev last night but I'll go that just to make sure but last time (pre-sensor replacement) both sensor 1 readings were almost spot on

Questions:
- The obvious one, any ideas on what the issue might be?
- Does the car use this sensor for anything besides closed loop trims?
- The previous questions is based on how concerned should I be about the code if there are no other codes popping up? In open loop (i.e. under acceleration) shouldn't the car use the program defaults my tuner set and not cause any issues?
- One of the possible causes listed with that code is fuel pressure/fuel injectors. Wouldn't I get other codes with it if I had a faulty injector? Also wouldn't the car run a little rough if there were fueling issues?

Well the first thing I thought was a pre sensor air leak? You looked at that gasket already but can see the whole thing ? Can you get your hands on a mirror stick and look up there? you can also try sticking a piece gasket down there and rev the car and see if there is any exhaust coloring on it? Paper might work too but not sure if it catch fire with the exhaust temps( Piping)

you can also use the soap water test on the intake pipes , Spray the connecters down ?

I tried my best with my mirror but there is just too much stuff in the way. It came on last night on my drive home and I didn't have enough time to start tearing the car apart and have it back together for work this morning.

The gasket in question is post sensor. So unless there is a leak at the header itself, any pre-sensor leak would have to be in the intake piping. Correct me if I'm wrong but the leak would also need to be post-MAF sensor. Also if I had a leak post-sensor I would expect to pick up a change in my Innovate which is in the downpipe.

The gasket/paper idea sounds good. I'll have to see if I can get something in there.

it could also be post-MAF sensor yes. Could be the MAF itself also? Another thing I was reading was it could be a bad coil pack?
" When the engine mis-fires, it sends a slug of unburned fuel and air into the exhaust stream that flows down to the sensor and can throw a p2a00 code"
From Motordyne.

I would expect a mis-fire to have other codes associated with it.

Might not be a complete misfire p300 tho. ? IDK just something else I was reading. :/

Anybody with knowledge of what the ECU sensor uses the fuel trim sensor for outside of closed loop?

I guess in simple terms, in addition to any solutions, I'm asking if there would be any open loop safety (engine) related to that code?

I've had the random misfire come up in the past but I had the sensitivity turned down because it was related to high idle rpms and lightweight aftermarket flywheel making a bunch of noise.

Check for vac leaks by spraying carb cleaner all along the intake tract, after the MAF, up to and around the IM gasket -- no change in idle means no leaks. You'll have to get it on a lift to check around the O2 bung on the header.

If no evidence of any vac leaks then do some datalogging with cipher.

Confirm similar voltage on bank and 2 MAF's and also log AFR and AF voltage readings on both primary O2's (note that weirdly cipher sometimes labels both as "bank 1"), fuel trims, and heater sensor correction %.

Wildly different voltage between the banks points to one sensor or the wires (if you have extenders) or both being bad -- based on that code, Bank 1 should be skewing way lean compared to Bank 2. You will also see massive fuel correction when that happens as the ECU tries to catch itself and keep on target.

Also note heater correction %: Low correction (say up to 30%) means normal warm up; high correction (close to 100%) means bad sensor, bad wires or both (usually bad sensor).

I just had similar problem, same code (same bank, in fact) eventually started getting constant low heater code for that bank.

New sensor already ordered.

If you find no evidence of different voltages, corrections etc, then its random and meaningless... however, I'm betting on a bad Bank 1 upstream O2.

Haven't done the intake check yet but I went ahead and logged considering I was in the car waiting for it to cool down enough to turn it off.

Seems like everything is in order except the heater correction. Bank 1 is running 25% lower than bank 2. I just replaced the O2 sensor less than two tanks of gas ago. Is it possible the additional heat from the turbo, which is only a foot away (physical distance, flow piping its probably 18"), is causing the drop in heater temp on that side?

I was thinking about just turning off my rear of sensors. That's what I did on my 350z and never had a problem

In don't think so -- that's all based on a wire's voltage for a wire dedicated to warming up the sensor.

The heat could be killing the wire itself tho and causing misreads -- what are the values for each bank? Lower values mean the sensor is getting up to temp quickly (unless its a misread), higher values mean it can't maintain operating temps.

Are the O2 voltages and AFR'd different for each bank too?

Bank 1 is 28.8 and bank 2 is 36.

AFRs are basic spot on and match the innovate. Which parameter is AFR voltage as I'm not sure I logged that one?

The wiring I pulled out, which had no heat protection, looked perfect. I wrapped the whole sensor cable in thermo-tec sleeve before I put the new one in so I don't see how heat could be an issue. I also have the crossover turbo piping header wrapped and the turbo bagged. I don't think its heat on the wires.

Unfortunately this is the fuel trim sensor not the post cat sensor.

Ooo sorry my fault..

It happens. I'm actually going to remove my post cats too as it appears to make the idle AFR better.

I had this code with the base map. My tuner said this was a common issue with a turbo'd 370z. They smoke tested the intake and a predyno checkout, everything checked out a-ok. They ended up disabling the P2A00 code in my final tune.

Good to know. I emailed JTran to see what he thinks we should do.

:tup:

after you get rid of the cat there pointless...

I think both those values are within range.

You want to log MAS A/F -B1 (V), MAS A/F -B2 (V), A/F WB-B1 (V), A/F WB-B2 (V), A/F ADJ-B1, and A/F ADJ-B2. I'd also log INJ PULSE-B1 (ms) and INJ PULSE-B2 (ms).

It's also worth logging MAF voltage for both banks just to confirm you don't have something wonky going on that far upstream.

Unless you have a specific physical symptom where you can narrow down when the problem crops up (e.g., stumbling at idle), once up to normal operating water and oil temps, I would try datalogging at idle, low load/cruise, and maybe one pull to redline in 2nd gear.

Unless the way things are plumbed for the turbo are causing Bank 1 to just suck more air than Bank 2 (it's possible -- and if so, then you'd need to apply fuel correction to Bank 1 cylinders via uprev tune), it could be a bad sensor, a vac leak, sticking injectors, or a fouled or cracked spark plug -- in other words, un-metered air slipping in, failing injectors, or a bad plug can all result in a lean condition, or at least cause the ECU to think you're running lean.

The code you got points to bad O2, but really it just means that the bank stays leaner than targeted longer than it should, so any of the aforementioned could cause that.

The datalog (as well as inspecting for vac leaks and checking out the spark plugs) should help clarify -- good luck!

EDIT: Also, yes, it's a bit like the random misfire code -- you can get this code and not have any actual issues, meaning its a detection logic problem, possibly aggravated by changing things around for the turbo. If everything looks good, all values are in range, no loss of power or evidence of knock, then I agree -- just switch it off. Definitely confirm all is good first, tho'.

I have also disabled this code (P2A00) in my tune, and I have not had any problems with it off.

Same here.

I have this code and a random misfire code occasionally. I've barely been driving the car and was still searching for a solid fix. Planning on replacing the sensor soon but don't have a lot of confidence that will fix the issue. May wind up just disabling the code as others have done.

Did you start getting the random misfire code after you upgrade the clutch/flywheel. As I understand it the sensor is so sensitive that the chatter of the tranny and lightweight flywheel, along with a higher than stock idle rpm, will set it off. I got that code when I first installed the kit. I had my tuner turn down the sensitivity on the sensor that trips that code and I've had no issues since. If I recall properly he just lowered the sensitivity under 1500 rpms.

Sounds like I'll disable it too if I can't find an actual cause. I'm going in for a retune in a couple months anyway so my tuner will have a few days to play with it and get it dialed correctly.

I had this exact same code last year. GTM Stg1 SC. turned out to be a bad injector. one was barely firing and the others were dumping a **** ton of fuel to compensate. Might be worth looking into.

Keep in mind Jwick that most if not all tuners turn off the misfire code. So if one cylinder is misfiring you wouldn't otherwise know it. When I turn on my launch control I cut fuel so that cylinders misfire, the with that code off thinks everything is just fine.

Mine isn't turned off. JTran just reduced the sensitivity of the random misfire portion below 1500rpms. I haven't had that code pop up since he adjusted it. The rest of the misfire codes are still OEM settings.

But is there a chance that your issue lies below 1500rpms?

Maybe I'm missing something. Only the random misfire code was messed with. The other individual cylinder misfire codes are still active. If I had a true misfire wouldn't a specific cylinder code pop up?

It is possible my issue is below 1500rpms, and I was below when it tripped the code this time around. The code popped up when I pulled up to the stop light and the idle hiccup happened (BP guys know exactly what I'm talking about). I had just left the work parking garage so the car wasn't really warm yet. The rpms dipped lower than on a 'typical' hiccup and the code came on. My thought is as it stumbled (hiccupped) the rpms dropped lower than normal and left it in a lean AFR state that tripped the code. All the parameters I've checked are spot on. All the bank readings are the same for each parameter except the sensor heater voltage (which Bank 1 is about 25% lower than Bank 2). Car runs find, idles fine, and in slight boosting applications it operates fine. I've not given it a WOT until I can absolutely confirm everything.

I picked up a new can of carb cleaner and I'll check the intake piping this weekend.

You wouldn't necessarily get a cylinder specific code.

When does the stumble hiccup happen? That may give a clue. When datalogging (or reviewing it later) take note of what the voltage readings are doing, as well as load and TP.

I think the heater correction is normal for both -- the difference may or may not reflect anything.

Once you confirm no vac leaks, no bad spark plugs, and injectors are working fine, all that's left is to check the O2 sensor (or just replace -- Denso p/n is 234-9104), wiring, and connector. If all is good then assume its just bad detection logic until a clear symptom presents itself.

You should be able to narrow it down between cipher and checking those few specific mechanical issues.

Finally, if the problem is consistent and can be narrowed down to a specific load range,you can always tweak the Bank 1 fueling in uprev.

The hiccup is the same for all BP kits. Happens right as you pull up to a stop. Rpms dip a bit and car goes lean then rich before it stabilizes itself. The going theory is the fact that the kit vents crank case instead of routing pcv back into it. Like the ECU is expecting it. Galeforce has a thread on here that I can't link cuz I'm on the cell. Mitch is very familiar with it too.

I'll admit that although I'm mechanically sound what goes on in the ECU and tuning software is somewhat new to me and I'm not very good at understanding the meaning of what I'm seeing.

Hmm. That shouldn't cause it unless its pulling vacuum, although its possible that it is... see further here Pcv Valve For Turbo & Centrifugal Apps - Forced Induction and Nitrous - SilveradoSS.com

In any case, your sensors sound ok, and it sounds like this is a common problem. Maybe include a PCV and vac line and/or catch can? If OEM PCV isn't up to it, I know there are aftermarket PCV's for boosted applications.

Jordo, take a look at the thread and let me know if you have any ideas. Thats the best one I got, and I plugged the vac lines going to the intake manifold and atleast around idle the problem seemed much better. Didnt want to drive it like that because I first want to get a catch can.

http://www.the370z.com/tuning/93796-...induction.html

We would have to tap the intake piping to route the PCV back into the system. Currently it's vented with no nipple to attach to on the intake piping leading up to the throttle body.

I'm very interested to see what happens when Mitch gets a catch can and is able to drive around without the PCV system completely.

On a similar note I order my O2 bung plugs and will get my tuner to update my map to disable the code this week. See how much that helps the idle issue. Any true tuning updates will have to wait until I get the V1.5 piping.

I think for both you guys, welding a nipple for a PCV or setting up catch cans is the only solution.

At light load, you guys are clearly pulling vacuum, so that means you need a regulatory valve to fix.

Either fix will do, because it will result in a closed system -- than means no more unmetered air slipping in.

The only other solution I can see would be trying to have a PCV before the open filter? Then the crankcase filter becomes a one way vent.

Just throwing out some ideas to try...

So has anyone found a fix for this yet? I'm hesitant to start replacing expensive sensors if that's not the issue. If it's harmless, then I guess I could have the code disabled. If there's some risk, then I want to find a real fix. Anyone tried Jordos suggestions?

Hasn't come back sonce I reset it last time. Of course the G isn't my daily anymore so it doesn't get as many miles.

Short story long, I've made no changes

Gotcha. I don't drive mine much either but it always comes back eventually.