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Discussion Starter · #1 ·
Hey all,

First post here. I'm posting on behalf of a friend and I'm trying to fix her car. We are in Maryland and she is trying to get her car to pass emissions. I think it's a 2001 325i. I know it's an e46.

Anyways, she had the p0441 code. I cleared the codes and it came back so I replaced the evap purge valve. I reset the codes again and the code has not yet come back but now the readiness monitors are not all coming back to ready status. I'm hoping I can get some help from you guys. Below is a screenshot of my scan tool findings. Any suggestions you all have would be great.



You can see the ones that are available and not complete. I can't pass in Maryland without those showing ready. She's already driven the car over 180 miles since the repair and code clearing. All conditions - steady low speed, steady high speed, high battery load, everything I could think of.

Help!

Thanks a lot.
 

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The Secondary Air System should be the very first item to clear on the first cold start.

Evap is usually the hardest and last monitor to clear.

I would guess you have at least 1 lazy O2 sensor causing the issues with your monitors.

Suggest you read this thread - http://forum.e46fanatics.com/showthread.php?p=16148512

You can determine exactly which O2 sensor(s) are bad by finger printing/graphing the sensors on cold start for 3 minutes without driving the car.

Not familiar with your OBD tool, looks like a smart phone tool? If so, it should be able to at least gather the OBDII data on cold start for the O2 sensors.

Usually 2 cold starts with about 10-15 miles of steady highway driving should clear all Emission Readiness Monitors. No more than about 25 miles of driving is all that is needed to clear the Readiness Monitors.
 

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Most likely a pre-cat O2 sensor, probably only one that is bad, but not a bad idea to consider replacing both. But if you are on a budget, then just replace the lazy one and move on for now.

I usually only use Bosch O2 sensors, used to get them on Amazon for around $50 each, however, I think they have gone up in price.
 

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Discussion Starter · #5 ·
Great, I'll try to get a log tonight before leaving work and I'll post it here. I should be able to post a file from the app right? That'll help you determine which sensor is lazy?

thanks again
 

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If you cannot easily graph the sensors on the tool, save the data to a .CSV file which can be imported onto other programs for graphing.

Usually you only want the 4 O2 sensors and maybe the engine RPM as a reference. Turn off all other sensors and try to get the logging interval to 1 second.

Do not drive the car, just start the engine cold and get 3 minutes of data without driving or touching the throttle.

You can email a .CSV file and I can graph it if you have issues.
 

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How long are you waiting for them to clear?

You need to complete "qualified" drive cycles. You can look up exactly what a drive cycle is, but it starts from a cold engine start and has several specific qualities that must exist else the trip is not a drive cycle. If you are not doing the proper drive cycles, then the monitors will keep resetting. Of course, if the monitors are not happy with the performance of the respective systems, then they will not complete either.
 

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Discussion Starter · #8 ·
jfoj, I just looked through my app and it gives me so many options for o2 sensors. Which do I need? Voltage, voltage wide range, lambda, lambda wide range...

jdStrickland, we did a couple different suggested cycles a few times. No luck.
 

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Usually takes about 2 weeks of driving to get them all to set.
Only takes 2 weeks of driving to set when there are problems with systems or sensors.

I can get almost any car or truck that has no problems to clear Readiness Monitors in under 20 miles. If the SAP does not clear on the first start this usually means there are problems.
 

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How long are you waiting for them to clear?

You need to complete "qualified" drive cycles. You can look up exactly what a drive cycle is, but it starts from a cold engine start and has several specific qualities that must exist else the trip is not a drive cycle. If you are not doing the proper drive cycles, then the monitors will keep resetting. Of course, if the monitors are not happy with the performance of the respective systems, then they will not complete either.
Readiness Monitors are tripped or toggled to Ready, they DO NOT reset unless an OBDII tool is used to clear codes or the battery is disconnected for a LONG time on some vehicles.

Once the parameters are met to toggle the Readiness Monitor to Ready or Clear, then they stay that way. I
 

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jfoj, I just looked through my app and it gives me so many options for o2 sensors. Which do I need? Voltage, voltage wide range, lambda, lambda wide range.../QUOTE]

Usually the tool only displays the data for the specific type of sensor. The car you mentioned should have standard O2 sensors, not wideband. You need to graph the O2 sensor Voltage.

Graphing is usually a different feature that involves actually recording the OBDII data PID's that you want. Only graph the O2 sensors and RPM. See the graph in the link I provided above.
 

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Discussion Starter · #13 ·
Ok, so I just tried it. I have no idea how to get the thing to save the graph it took so I took a screenshot of it. The numbers down the bottom show how many seconds. I took this shot at 3 minutes.



That's all at idle from a cold start. The red zigzag started about 35 seconds in. I also have a freeze frame snapshot of the sensors if that'll help.

Thoughts?
 

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Well this is a real train wreck from the graphing standpoint.

Again, I do not know the App you have.

IF and IF, the graphs are close to correct, I would question sensor Bank 2, Sensor 1, however, it is possible that both sensors may be in question.

But I will say the graph you have is not even close to what I would expect to see for performance. If the polling interval is too long, this will give very bad graphing details. It is also not clear how the vertical scaling is functioning.

If you look really close at the graph I posted in the link, you can see exactly how things are supposed to look over a 3-4 minute period and a lazy O2 sensor will be so obvious it will knock you out of the chair.

The other amusing thing is a lazy sensor like the one in the graph in the other thread will never be picked up and flagged by the DME. That's right, no CES/SES/MIL or and DTC's!

The Torque Pro App for Android is $5 and will graph like I would need to see the data. Not sure you could use the current BT interface that you have?? It appears your App will ONLY recognize the specific BT interface, but if you can connect the BT interface with a different phone even without any App then maybe you can use your interface with Torque?
 

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Torque is much better in my opinion.

Still not ultra intuitive, but has the ability to do the job.

Make sure you turn off all logging for everything you can other than O2 sensor Voltage and RPM.

Set polling interval to 1 sec.

Get Torque ready to start, have BT connected and then start the logging once you turn the ignition on, but do not start the car until Torque is connected, usually takes about 30 seconds.

Do not worry about actually seeing the graph on Torque, it is best to import the data to Excel or another program and graph the data.

I can graph the CSV data if needed.
 

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Yep, there is a problem, it is likely with one or both pre-cat O2 sensors. The SAP Readiness Monitor will clear on the first cold start on these cars if the SAP system is functioning properly AND the pre-cat O2 sensors are not lazy.

On problem cars that the Emission Readiness Monitors will not clear, the longer you drive the car, the more likely you may be to actually start the car in the proper conditions to finally start ticking off Readiness Monitors, however, if you cannot get them cleared in short order, there is a problem with the car.

I can almost guarantee the OP that at least 1, if not both of the pre-cat O2 sensors are lazy. Might even have a post-cat sensor issue, but less likely to show up for the Readiness Monitors.

Giving the OP actually has the Evap Readiness Monitors cleared, the car has been driving at least 15-20 miles, or easily long enough for the monitors to clear.

You can see in the thread I posted in this link the person had problems with tripping the SAP and a few other monitors. He graphed the cold start, I found a lazy pre-cat sensor, he replaced it and in the first cold start the SAP cleared and I think he drove the car about 10 miles an all but the EVAP had cleared, but this was enough for the car to pass inspection. I think the EVAP cleared in the next few days once he drove on the highway for a few miles.

I deal with these issues all the time and they are not really that difficult to resolve.

If the OP here does not want to gather data and roll the dice, replace both pre-cat O2 sensors I am pretty confident that his Readiness Monitors will clear within the first 2 days of driving.

But I prefer to gather the data if possible, if may save the OP some $$ to only replace what is needed for now. Also many of the forum members can learn from this and other similar cases on how to resolve the hard problems.

You want to read about a nightmare case that the owner kept playing Whack A Mole with and finally resolved with forum help, check this thread - http://forum.e46fanatics.com/showthread.php?t=954362
 
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