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.

 

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.

 

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.

 

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 ?