P0130 and P0446 error code

Hey I have a 99 that I bought in Feb and a couple of months ago the CEL came up, similar code, cleared it and then it didn't come up for a while. Then it popped up and cleared by itself. Now it's back. I tried cleaning the MAF, didn't clear the code. I have a new MAF that I might put in. Thoughts? Something I should really dive into? The Red mark below is a Red Exclamation Mark on the code reader.

PO446 is EVAP canister shut off valve. PO130 is oxygen sensor ahead of catalytic converter bank 1 short circuit or limited voltage increase. Sounds like two unrelated faults and nothing to do with the MAF.

got it. anything that I should be concerned about right now? could this lead to more serious things? Is it serious?

Well, whatever it is, apparently it costs "$17" to fix it.

I think that if the mixture is off due to PO130 there is the possibility of damaging the catalytic converters. I don't think that P0446 will lead to a greater problem.

but that's with "Generic" parts hehe I'll have to do some work in there soon, replace the starter that's cranking too slow, and sometimes doesn't start, that's not fun, especially with people around haha. And some minor seeps here and there.

Agree with George996. If your scanner can read real-time O2 sensor voltage, just read the voltage of all 4 sensors and compare them between the banks. It should then be obvious if bank1 pre-cat O2 sensor is bad. Pre-cat O2 reading should swing between 0.7v and 0.2v about once a second and the post-cat O2 reading should stay flat at around 0.6-0.7v . All taken at a fully warmed up idling engine.

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I read the live data on the reader, but not sure which ones I should be looking for. Here's the data they're listed as I took them first read starting at 0 seconds 00:00 O2B1S1(V) 0.800 G 00:02 O2B1S1(V) 0.120 G 00:06 O2B1S1(V) 0.545 G 00:09 O2B1S1(V) 0.125 G 00:11 O2B1S1(V) 0.105 G 00:13 O2B1S1(V) 0.150 G 00:15 O2B1S1(V) 0.130 G 00:18 O2B1S1(V) 0.135 G 00:21 O2B1S1(V) 0.805 G 00:23 O2B1S1(V) 0.810 G 00:00 O2B1S2(V) 0.220 00:02 O2B1S2(V) 0.350 00:06 O2B1S2(V) 0.180 00:09 O2B1S2(V) 0.530 00:11 O2B1S2(V) 0.545 00:13 O2B1S2(V) 0.520 00:15 O2B1S2(V) 0.255 00:18 O2B1S2(V) 0.195 00:21 O2B1S2(V) 0.130 00:23 O2B1S2(V) 0.105 over a period of 57 seconds 00:00 OB2S1(V) 0.075 00:02 OB2S1(V) 0.090 00:08 OB2S1(V) 0.065 00:15 OB2S1(V) 0.805 00:26 OB2S1(V) 0.800 00:27 OB2S1(V) 0.775 00:30 OB2S1(V) 0.770 00:34 OB2S1(V) 0.100 00:37 OB2S1(V) 0.765 00:54 OB2S1(V) 0.780 00:57 OB2S1(V) 0.780 00:00 O2B2S2(V) 0.685 ? 00:02 O2B2S2(V) 0.690 ? 00:08 O2B2S2(V) 0.690 ? 00:15 O2B2S2(V) 0.775 ? 00:26 O2B2S2(V) 0.729 ? 00:27 O2B2S2(V) 0.715 ? 00:30 O2B2S2(V) 0.705 ? 00:34 O2B2S2(V) 0.700 ? 00:37 O2B2S2(V) 0.685 ? 00:54 O2B2S2(V) 0.655 ? 00:57 O2B2S2(V) 0.655 ? Vehicle was warm and idle.

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it would be better to view the data plotted against time so you can see when the values change. However in the meantime, B1S2 looks incorrect, voltages should be more look like B2S2. The other sensors look ok assuming the voltages change at the right time. Later i will post the diagnostic procedure for P0130.

Thanks George, I updated the readings with the time. On my O2 Monitor Test O2 Bank2 Sensor11 reads with a "?" not sure what that means.

If those are the only data points within the measurement periods (60s and 90s), your scanner is not fast enough to show the sensor reading. The scanner needs to read (and report) at least 4 samples per second per sensor. B1S1 is bank1 precat, B1S2 is bank1 postcat B2S1 is bank2 precat and B2S2 is bank2 postcat You code is complaining about the B1S1 reading. B2S2 (or B1S2) may stay at low voltage for a while in some cases but if you blip the throttle a bit, it should come back up to 0.6-0.7v steady during idle.

The reader gave me more readings, there are just the ones I managed to snap with my phone, that's how I "noted" them down.

Reads like the indicated O2 sensor is bad. Wth the OBD2 code reader/data viewer you have if you can watch the #1 and #2 #1 sensor readings simultaneously you will probably how the bad sensor's readings differ from the other sensor's readings. The engine *should* probably be warmed up as it was fully warmed up when the error appeared. Unless you have been at the engine recently and might have damaged the wiring the sensor is probably just due to be replaced. If both #1 sensors are the same age both should be replaced. Get the P0130 error solved then tackle the P0446 error. This is pointing to something amiss with the secondary air injection system. You can return the new MAF.

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I see. Do you know roughly how much time between each sample?

yes, the camera records the time, I added it to the readings Over a period of 23 seconds, each reading list time the reading was done, so i.e. at second 6 the reading was 4 seconds after the previous reading. 00:00 O2B1S1(V) 0.800 G 00:02 O2B1S1(V) 0.120 G 00:06 O2B1S1(V) 0.545 G 00:09 O2B1S1(V) 0.125 G 00:11 O2B1S1(V) 0.105 G 00:13 O2B1S1(V) 0.150 G 00:15 O2B1S1(V) 0.130 G 00:18 O2B1S1(V) 0.135 G 00:21 O2B1S1(V) 0.805 G 00:23 O2B1S1(V) 0.810 G 00:00 O2B1S2(V) 0.220 00:02 O2B1S2(V) 0.350 00:06 O2B1S2(V) 0.180 00:09 O2B1S2(V) 0.530 00:11 O2B1S2(V) 0.545 00:13 O2B1S2(V) 0.520 00:15 O2B1S2(V) 0.255 00:18 O2B1S2(V) 0.195 00:21 O2B1S2(V) 0.130 00:23 O2B1S2(V) 0.105 over a period of 57 seconds 00:00 OB2S1(V) 0.075 00:02 OB2S1(V) 0.090 00:08 OB2S1(V) 0.065 00:15 OB2S1(V) 0.805 00:26 OB2S1(V) 0.800 00:27 OB2S1(V) 0.775 00:30 OB2S1(V) 0.770 00:34 OB2S1(V) 0.100 00:37 OB2S1(V) 0.765 00:54 OB2S1(V) 0.780 00:57 OB2S1(V) 0.780 00:00 O2B2S2(V) 0.685 ? 00:02 O2B2S2(V) 0.690 ? 00:08 O2B2S2(V) 0.690 ? 00:15 O2B2S2(V) 0.775 ? 00:26 O2B2S2(V) 0.729 ? 00:27 O2B2S2(V) 0.715 ? 00:30 O2B2S2(V) 0.705 ? 00:34 O2B2S2(V) 0.700 ? 00:37 O2B2S2(V) 0.685 ? 00:54 O2B2S2(V) 0.655 ? 00:57 O2B2S2(V) 0.655 ?

take a look at the attached. it describes more than just a short circuit. As i mentioned, B1S2 is still incorrect although the fault code addresses B1S1. Hope this helps

Ok, I see now but sorry, the sampling was just too slow to conclude anything. The reason is the precat sensor voltage should swing between 0.2-0.7 about once a second and you need to show at least 4 samples per second to see that pattern. Your samples are seconds apart so it's possible the swing pattern is there but the tester just happens to sample a few consecutive high points or low points. Or the signal really flatlined for a few seconds between samples. Without more samples in between, it's impossible to tell. If you have an Android phone, you can get a very cheap <$20 OBDII dongle with the Torque app to read the same, but at a much higher sampling rate.

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Ahsai, you are correct. I more or less said the same thing about having the data plotted against time so the intervals can be monitored. Regarding B1S2, i am making an assumption that it never goes rich (barely) but it is an assumption.

BTW, you can try swap the precat sensors between the banks, reset the codes and wait for the CEL to come back on and see if the code follows the sensor. If it does, it's the sensor, otherwise, it's the wiring or the heater relay/circuit of the bank1 precat sensor.

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Yes, that's how I understood your previous post.

I'll try reading it again tomorrow, and use the record live data funtion on the reader. I belive I can connect it with usb to my computer so let's see if I can get more meaningful and complete data. Ahsai, swapping the sensors sounds like a smart idea. by the way the CEL light turned itself off when I drove home today, before I did the tests.

If you can capture the data starting when the engine is cold, that's even better. That will very clearly show the full dynamic range of the sensor and the swinging pattern. It will also confirm correct SAI operation, not that it's your problem now Porsche-cold-start-SAI-O2-reading.jpg

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mhariush take a look at the diagnostic procedure i attached and look at the diagnostic conditions p0130 because it says that there should not be any faults with the fuel tank ventilation but you do have have one, po446. Now i am thinking that the other fault code is causing this po130, especially since B1S1 seems to be working.

here is po446

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Good point George.

Thanks guys, that's an interesting point. I will prob not have time to do anything about this until after the holidays, I'll be out of the country. But I'll look into it when I get back. But a faulty fuel tank ventilation isn't something that should cause any problems is it?

Had the car inspected at House Automotive today and the P0046 error was caused by the Ignition Control Valve.