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Annoying P1093

24K views 104 replies 9 participants last post by  Corbster 
#1 ·
Hey guys, for half a year now, I've been trying to get rid of this generic p1093 code. Car runs great though. Fuel economy seems decent too. What's interesting though, is that my generic scanner says something totally different than the other posts I have read about this code. It says "manf. Cntrl fuel& air metering, auxiliary emission controls." So far I have replaced the following..

All four o2 sensors
All spark plugs
Fixed all vac leaks
Fuel filter
Heavy duty air filter with stupid cotton layer under it. Could that be it?

I heard I'm still looking at bad MAF, leaky injectors, or fuel pressure regulator. Does this sound about right or should I start looking else where? Thanks

Ps.. if my obd2 scanner seems to be reading the maf and showing changes when I press the throttle, is it safe to say that's not my problem?




Sent from BimmerApp mobile app
 
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#44 ·
This is what I wrote long time ago on EVAP test.
EVAP test is run after engine is shut off.
Needs 5 hours cold soak between the EVAP test, minimum 20 minutes drive before engine shutoff, and requires two consecutive passes. That's the reason EVAP test is hard to satisfy.

I found an official E46 requirement for EVAP test.
You need to follow these requirements by teeth.
Fuel level should be 1/4 to 3/4.
Engine should not be started for 5 hours before test cycle.
Car need to be driven more than 20 minutes.

So drive to work taking at least 20 mins or longer, then let is idle for 3 minutes to complete the test. Do same when arriving home. Note that EVAP leak is tested every second time the conditions are met.

BMW official guide for
SIEMENS MS 43.0 ENGINE CONTROL SYSTEM
Model: E46 equipped with M54 Engine
Production Dates: M54 B30: from 6/00, M54 B25: from 9/00

LEAK DIAGNOSIS TEST PRECONDITIONS:
The ECM only initiates a leak diagnosis test every second time the criteria are met. The criteria
is as follows:
• Engine OFF with ignition switched OFF.
• Engine Control Module still in active state or what is known as "follow up mode" (Main
Relay energized, control module and DME components online for extended period after
key off).
• Prior to Engine/Ignition switch OFF condition, vehicle must have been driven for a minimum
of 20 minutes.
• Prior to minimum 20 minute drive, the vehicle must have been OFF for a minimum of 5
hours.
• Fuel Tank Capacity must be between 15 and 85% (safe approximation between 1/4 -
3/4 of a tank).
• Ambient Air Temperature between -7 deg C & 35 degC (20 F & 95 F )
• Altitude < 2500m (8,202 feet).
• Battery Voltage between 11.5 and 14.5 Volts
When these criteria are satisfied every second time, the ECM will start the Fuel System Leak
Diagnosis Test. The test will typically be carried out once a day i.e. once after driving to
work in the morning, when driving home in the evening, the criteria are once again met but
the test is not initiated. The following morning, the test will run again.​
 
#47 ·
This is what I wrote long time ago on EVAP test.
EVAP test is run after engine is shut off.
Boomer,

I believe you may be mixing things up a bit, no disrespect intended here.

The EVAP test MUST be run with the engine running and the vehicle in motion because the Evap Purge Valve needs to be triggered to open and actually pull a vacuum on the charcoal canister which typically only occurs during a steady light throttle cruise at speeds probably at 40-45 MPH or higher. Did not try and find if there is specific data, but this is what I have found to be mostly true over the years with the many cars I have dealt with.

I think what you are referring above is the LDP (Leak Detection Pump) system that is used on the earlier models to actually pressurized the fuel tank and associated lines to check for EVAP line and fuel tank air leaks. The LDP system does in fact only run when the car is shut down.

But this may be part of the reason the EVAP system does take much longer to clear on earlier cars with the LDP system, assume the LDP test cycle has to run and pass before the EVAP system has to run and then pass. So this may mean on earlier models the EVAP may take as long as 3-4 or more start and drive cycles along with the specific driving conditions to trigger the EVAP system to operate.

The later models do not have the LDP system as I recall. I have not bothered to become overly versed in the BMW EVAP system because from my perspective it is typically pretty trouble free. I personally have not seen a lot of problems with the system, however, the most problematic issue with the EVAP system on the later models tends to be the EVAP Purge solenoid under the hood that typically triggers a code for an open circuit and more often than not replacing the EVAP Purge solenoid solves this specific code.
 
#51 ·
Ok so the CEL finally popped up, but this time it's for P1092.. That's lean on bank 2. Somehow I feel this is related to the p1093 code on bank 2. Is it possible a bad o2 can keep confusing the ecu like this or possibly even a dying catalytic converter on bank 2 since I had that pending code for the cat on bank 2 a few weeks ago? Somehow I don't think the car is actually running lean since it's not misfiring or anything and runs the same.
 
#52 ·
I had to start over from the beginning on this thread to try and get the back story straight.

I think it is time to graph the O2 sensors.

A few questions, what is the build month and date of this car?

Do you know if the pre-Cat O2 sensors are 5/6 wire or 4 wire sensors?

Lets try to gather the O2 sensor data.

Also do you know for sure the O2 sensor wiring is all correctly plugged in?

Since you have the BMWhat App as well as Touch Scan?

I would like you to read the codes next time the SES/CEL/MIL comes on with both tools, I just want to see if there is any inconsistency between the tools.

I would like to stat with looking at the O2 sensor Voltage from cold start and just letting the car idle for 3 minutes, if you could also capture Engine Temp, MAF Grams/Sec, RPM and Fuel Trims in this it would be helpful as well.
 
#53 · (Edited)
Thanks for the quick response jfoj.. I will get you the graph for the cold start asap. I think I figured out how to save the data even though the developer told me you can't when I emailed them.

Anyway, shortly after my post today, the CEL cleared on it's own after a few drive cycles. Of course the p1092 is still stored on the touch scan. Now, the Bmwhat app, tells a different story.. here's 2 screen shots below.. Text Font Technology Screenshot Games
Text Font Games Technology Scoreboard


So even though most of the time the 2 apps are telling the same story, they aren't doing so this time. Also I'm sure everything is plugged in correctly because everytime I'd switch the connections around, I'd get rough idle and instant o2 circuit codes. I'll also get back to you on how many wires they have. The prod. Date on the car is 12/02. Pretty sure they were 4 wire
 
#56 ·
Hey jfoj, I finally got the Torque app, but for some reason you can only graph 2 sensors at once. I need to graph all 4 at once during the cold start, no? I could do this with Touchscan, just couldn't get the info out to you.. Maybe you can tell me how to graph these o2's so I can just do it myself and be done with it? Im pretty sure the problem is with the CAT though, cause it never became ready after all this time..
 
#57 ·
You should be able to do it without a problem, BUT, I have seen issues from time to time where in Torque you will select the O2 sensors, maybe after other PID's/sensors and the O2 sensors will not graph.

So often I have to clear out everything that you want to graph, then start with the 4 O2 sensors adding them to the

From the main Torque page, push the Android Menu soft key, choose Settings, choose Data Logging & Upload, choose Select What To Log. You can push and hold the Android soft Menu button down and you can choose to Clear All. The start by selection JUST the O2 sensors and maybe Engine RPM.

I turn off all the GPS and other garbage as well.

Here are some links that may be useful:

http://forum.e46fanatics.com/showthread.php?t=1045691

http://forum.e46fanatics.com/showpost.php?p=16250834&postcount=17

http://forum.e46fanatics.com/showpost.php?p=16215221&postcount=5
 
#58 · (Edited)
Ok thanks a bunch. But do you think there is even a point to play around with the o2 sensors when theres an obvious issue with the catalyst system not becoming ready for a few months? Or is it possible bad o2's can cause the cat system to not be ready?

PS: Touchscan is such a pleasure to use compared to Torque. Aside from the constant disconnects from Torque, Touchscans interface gets straight to the point with a much easier to understand layout. Shame you can't save graph info on it.
 
#59 ·
I do not have Touchscan but I have OBDLink which is the OE version of Touchscan that is shipped with the OBDLink Interface.

OBDLink does appear to log, but it is a bit tricky to find the info.

You have to set up and open a Vehicle Profile, then open/choose the Vehicle from the Vehicle Editor.

Once the Vehicle is selected, go to Logs, then select Files in the upper part right of the screen. Then you should find multiple .csv Logs if you have any.
 
#60 ·
While I get the torque data together, might you be able to see anything from this 3 minute touchscan very cold start(20f) idle data I posted below? I took screen shots every thirty seconds or so.. Please let me know if you see anything suspicious..
 

Attachments

#61 ·
Unfortunately most software writers and App developers have NO IDEA about how to graph things! Most graphing on tools is pretty useless.

If you look carefully, I am almost positive that TouchScan has .csv files saved. Like ALL of these Apps, finding the magic button or location is a PITA.

So here is what you need to do, it is confusing because depending on the rotation of the phone there are different things displayed on the screen to push/access.

On your Landscape graph view, look closely at the top of the screen. Notice "GRAPHS" and then look for the small triangle to the right of "GRAPHS". The small triangle means there are Sub Menus under "GRAPHS". Touch "GRAPHS" and find "FILES". Under "FILES" will be each CSV log which is FAR more useful for graphing outside of the App and on a computer using a different program.

Touch a CSV file, then choose Share and then email it to yourself. Set up a free DropBox account and upload this file to DropBox, then you can post the link to share the file from your DropBox account.

Special note, if you have a the "Logs" page open while the phone is in Portrait mode, you will see "FILES" on the far right side of the screen and you can access the CSV files from this "FILES" option.

I believe if the App is configured correctly it will Log CSV file each time you connect to the vehicle.

The only small issue I see from the PID data is one of the Post-Cat O2 sensors seems to have a Voltage that appears too low, however, this is just a single snapshot and I will need to see what is happening during the 3 minute cold start.

Again, graphing on most tools, even a lot of the "Pro" tools is subpar as far as I am concerned. I can do a much better job graphing exporting the data to a 3rd party program and picking and choosing what and how I graph things.

Graphs are very powerful tools, but few people understand how to set up and display the data. Sad but very true, I have been graphing and using visualization for for years and I am still what I would consider somewhat a "Novice" but I know what and how I need to set up and display the date so the information is useful and insightful.
 
#63 · (Edited)
CSV data is the way to go, prefer RPM and 4 O2 sensors 3 minutes from cold start.

Then 3 minutes at idle once fully warmed up, this will be the simplest way to start.

I cannot comment on what I cannot see or a single snap shot of data.
 
#68 ·
Sorry, I knew there was someone that had some graphs to look over.

Here are the graphs, please download and attach back here because I have no more attachment space:

https://www.dropbox.com/s/yb8odt5q13xnxmc/Post Cat O2 Sensors Cold Start.jpg?dl=0

https://www.dropbox.com/s/853ep5ambxd1nsx/Post Cat O2 Sensors Warm Idle.jpg?dl=0

So for now, not 100% sure that to think about this.

What I can tell you is the following:

1. Be careful of the graphing colors, pay attention to the Legend so you do not mix up the Banks when comparing the 2 graphs.

2. The DME is not the issues, as the cold start Voltages look fine until about 2/3 into the graph where the Bank 1, Sensor 2 goes to Lean where it should look like the Bank 2, Sensor 2 and hover around 0.7 Volts.

3. I do no think the O2 sensor wiring is swapped/wrong polarity on the Bank 1, Sensor 2 because the initial warm up signature looks consistent with the Bank 2, Sensor 2 behavior.

4. It appears the Bank 1, Sensor 1 O2 sensor is working pretty close to normal from the cold start graph, maybe slightly slow as compared to the Bank 2, Sensor 2.

I do not recall the history on the O2 sensors, have any/all been replaced or are they original?

I am not sure how to tell you to proceed at this point. I am a bit puzzled as to the behavior of the sensor.

I do not think this is a catalytic converter problem, however, I am wondering of there may an air leak around this sensor location??

I hate to suggest swapping the O2 sensor location as a test as the PostCat sensors are a PITA to deal with.

It may be possible something is wrong/damaged with the Bank 1, Sensor 2 that is causing outside air to be sensed and indicating a Lean condition.

So I will wait to hear back from you with details about the O2 sensor history and if you have any ideas.
 
#69 · (Edited)
Thank you so much jfoj.. I really appreciate it. What program did you use to make that graph?

Anyway, the history on the o2's is they are all brand new Bosch i replaced maybe 6 months ago. Looking back at my old pictures, I had this code before I even replaced any sensors. Well the 1093 code anyway which has become the 1092 after the 1093 disappeared for a month after the MAF cleaning. So thats something to consider. BUT I think there is a possibility that air can be seeping past the sensor because when I was installing one of the post cat o2 sensors, one of them felt strange tightening up. It almost felt like it wasn't 100% snug. Felt 95% snug. Kept turning almost as if it was cross threaded but I've been doing this too long to know how to thread stuff properly. I made sure not to cross thread though by hand tightening first and it went in properly and the thread did not look damaged.

So I will raise the car up and check for any exhaust leaks coming from that location and make sure the sensor is installed properly, and will also check for vac leaks just to be safe. Again, I do find it very strange that the CAT has never become ready.

I will keep you updated with this PITA problem :banghead: :ben:
 
#70 ·
I read back that you had replaced all 4 O2 sensors at one point.

What I really needed to know is if you had the P1093 before the sensors were replaced.

Were they "direct fit" O2 sensors with the connectors already installed or did you need to splice wiring??

Do the post Cat wiring harness connectors look in good shape or does it look like some repairs/splicing may have been done in the past?

It seems like you had issues before.

I would say this would probably be a pretty good size air leak in the exhaust, could even be cracked welds around the actual O2 sensor bung.

Easiest way to sort this is to perform a smoke test on the exhaust system. Take a smoke machine, home made unit will work, connect to the tail pipe and fill the exhaust full of smoke and check for leaks.

Another simple test may be the following, if have the old O2 sensors, use an old Post Cat O2 sensor and actually connect it to the "good" bank and record the same colds start data, you might need 4-5 minutes as the O2 sensor will not be in the exhaust stream, but it will allow us to see if the O2 sensor seeing a lot of oxygen stays at the low Voltage similar to the Bank that is giving you problems now. I assume it will, but it would be worth seeing what the behavior is just so we have an idea as to what may be going on.

Try to post the graphs up here so others can see what you are dealing with.
 
#71 · (Edited)
The harness looks to be in perfect condition. And the sensors were direct fit bosch. I'm just waiting to find some time to start checking this problem further. I'll keep you posted.

And I did have the 1093 before and after sensor replacement. Except after maf cleaning, it disappeared for a month and was replaced by 1092 after the month. Thankfully I was able to pass emissions that time.
 
#73 ·
See if you can graph about 6 minutes with about half at a steady cruise.

I am thinking that the polarity of the O2 sensor in Bank 1, Sensor 2 is swapped.

I really need to see all 4 O2 sensors as well as RPM.

Something is really strange with your car, cannot quite put my finger on a specific issue yet, its really hard when I have to rely on just bits and pieces of data.
 
#75 ·
I understand, I only graphed with the Post-Cat sensors because the Pre-Cat sensors hide the Post-Cat graphs and make them hard to see.

I need to see what is going on once the car get running and at a steady cruise.

Something is not right with Bank 1 Post-Cat behavior.

You could try a test where you graph them 2 times and one time swap the connections for the Post-Cat sensors if this can easily be done.

I am not sure what it will tell us, but we can hopefully get some info out of the test.

Either the Bank 1, Post-Cat sensor was damaged when installing it, there is a lot of air leaking in around the Post-Cat sensor or somewhere in the exhaust stream. Maybe even an engine mechanical issue, however, I assume this would cause a problem with power, misfiring or some other issue.
 
#77 ·
Wish I could tell you exactly.

Could be a faulty sensor, BUT it starts out in the right Voltage window, unless somehow something is cracked/damaged causing it to read too low.

Air leak into the exhaust after the Pre-cat sensor.

BUT, this is why it would be helpful to see a mix of recorded data points with all sensors, vehicle speed, RPM, IAT and so forth.

Would like to see how the Pre and Post cat sensors are playing.

The Post ca sensors are a PITA, I would say swap the sensors and the wiring connections but it may not be such a nice project.
 
#78 · (Edited)
jfoj I have a few updates for you.. I did have a small exhaust leak afterall at the flanges where the manifold connects to the exhaust, but since it was past the post cat o2s, that did not help fix the code. I was able to get my hands on a quality scanner and picked up the BMW code 235 aka p1190. My other app BMWhats app, now known as Carly, actually has been pretty useful to me as of late pin pointing exact issues with the EWS, but thats a different story. Anyway, it has also been showing me that my problem lies with bank 1 upstream.. So I went ahead and swapped precat o2 positions.. No change in code.. So my question is, if I did have a failing cat, wouldn't my performance be pretty bad? My performance is great. Same thing goes for fuel pump.. Some were telling me a failing fuel pump is common as well.. Except I have great performance. Is it possible to have either of these 2 items failing with no symptoms? Thanks.
 
#79 ·
Did not re-read all comments from the beginning.

Best to do 3 Logs, all 4 minutes each. Add every sensor the DME supports, probably about 15 or so would be my guess.

1. Cold start, no throttle, do not drive.

2. Warm idle, no throttle, in drive if an automatic.

3. Steady cruise, 45-60 MPH range, try to find a very flat road, use cruise control if possible.
 
#82 ·
Can you please be a little more specific about which sensors you would like me to log, because in my OBD Fusion app, I see maybe only o2 sensors and MAF as far as sensors go.. The rest is like short/long term fuel trims, fuel rate, engine rpm/temp, etc. And there is alot more than 15 of them. Thanks.
 
#81 ·
Fuel pump is more likely to show symptoms.

But I cannot get an idea with a single code.

You claim the vehicle runs great, the DME says otherwise.

Now the trick is to find out who is wrong, you or the DME.

I find all sorts of screwed up things from prior owners or shops all the time.

Really would like to see the big data picture to see if the data supports the code that is being triggered. Freeze Frame info is also very useful.
 
#85 ·
I would have to go back and re-read 5 pages of this thread, however, looking at the Freeze Frame info, nothing sticks out.

I am starting to thing this may be a DME reflash if the Pre-cat O2 sensors have been replaced.

Also since this is a 2003, can you confirm if the Pre-cat O2 sensor are 4 or 5 wire?

This can make a differences.
 
#86 ·
They are 4 wire.. I replaced all 4 o2s a little over a year ago and I use to work at a euro Indy shop and the boss there gave me the latest update, unless reflash means something else? The update didn't really help anything. That was also a little over a year ago when I still had the p1093 which changed to a p1092 after cleaning my maf. It took a month for it to come back as the p1092 and I was able to pass emissions with many miles of driving. This time I was not able to. All I needed was evap to be ready to pass but the only time it became ready was the second the CEL came on. Catalyst of course was never ready
 
#87 ·
Get the 4 minutes Logs, maybe something else will stand out.
 
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