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2002 330ci-5HP-19, 2004 325ci-M56
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39 Posts
Discussion Starter · #1 ·
hello e46 and bmw community. i recently got a 2004 bmw 325ci with the m56 engine. when i got the car i checked the codes/monitors with a obd scanner. there were no codes and all the monitors were ready at the time. after about a week of driving the service engine soon light came on and it turned out to be a system lean code(s). i believe that code showed because the main intake hose was disconnected, i tightened the clamp properly. unless i have another vacuum leak i believe that was the issue with the SES light. i realized AFTER clearing the codes all the monitors were incomplete. i’ve driven over 200 miles and did two proper cold starts over the last two days. all the monitors are ready except the CCM, Secondary Air System and EVAP are still not ready. even after driving and doing a couple cold starts the CCM, SAS and EVAP will not get ready. i have no codes stored currently. the ambient outside temp is broken and always shows 122 degrees fahrenheit, wondering if that will impact this monitor. can anyone help with this?
 

· Premium Member
2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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2,558 Posts
Welcome to the forum.

Let’s get you set up
Have a read through the IMPORTANT LINKS page. There you will find threads about how to ask for help as well as fixes and advice on many of the common E46 problems.

A couple of helpful web pages:
  • Part numbers and exploded diagrams: www.RealOEM.com. Enter the last 7 digits of you VIN into the search tool. Bookmark the results, you’ll be back many times. Then browse for part numbers specific to your car.
  • Build spec. You’ll need a build spec as some parts have different versions for different spec vehicles. This link may or may not work, but it will give you a lead on getting a VIN decode: Free BMW VIN Decoder : ///M Decoder
  • E46 wiring diagrams: BMW WDS Online
Now let’s get back to your car problem.
See the attached file. While it is for the ULEV cars (M54), it will be very similar to your SULEV (M56). The coolant temp needs to be between -10C to 70.5C.

The only way the outside ambient temp could impact is if the DME is using it to determine if the cold start enrichment.
 

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· Registered
2002 330ci-5HP-19, 2004 325ci-M56
Joined
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39 Posts
Discussion Starter · #7 ·
You look at what is being monitored and what enabling/disabling items there are. Make sure all the enabling/disabling items are correct.
so for example to set the secondary air system monitor the air pump must be on, o2 must be heated up, cold start enrichment must be activated and coolant temp needs to be -10 to 70.5 etc. basically the secondary parameters need to be aligned with enable/disable conditions?
 

· Premium Member
2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
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2,558 Posts
how can i test my pre cat o2 sensors
1) With a scanner that shows you live data. The sensors should be switching/swinging in value. As you have a 2004 model E46, you will have wide band O2 sensors these swing around a 1 mA mark e.g. 0.94 to 1.06 mA with a hot engine at idle.

2) Check with a scanner that the O2 sensor heating is > 90%.

3) Set up OBD Fusion and run the 3 standard logs. Post links to the CSV files and we'll have a look.
 

· Registered
2002 330ci-5HP-19, 2004 325ci-M56
Joined
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39 Posts
Discussion Starter · #13 ·
1) With a scanner that shows you live data. The sensors should be switching/swinging in value. As you have a 2004 model E46, you will have wide band O2 sensors these swing around a 1 mA mark e.g. 0.94 to 1.06 mA with a hot engine at idle.

2) Check with a scanner that the O2 sensor heating is > 90%.

3) Set up OBD Fusion and run the 3 standard logs. Post links to the CSV files and we'll have a look.
 

· Premium Member
2000 E46 323i, 3.0L, 2.8L and 2.0L Z3's
Joined
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2,558 Posts
Your Scanner is showing the pre-cat O2's as mA values around zero mA. Both are cycling correctly.

Even though the engine was not up to full operating temp, the total fuel trims (STFT + LTFT) for both banks are showing around 20%. This indicated a problem.

The MAF value was in pounds/minute and not grams/second, so I have no idea if the MAF value is correct. Your 325CI should be drawing around 2.9 to 3.4 g/s at hot idle.

Read your first post again.
Whenever you clear the codes, it clears the monitors as well.

Running the required drive cycle usually brings the monitors back into "ready".

Suggested next step is to smoke test the engine and find the vacuum leaks that are causing the total fuel trims to be around 20%. Read: How to Smoke Test
 

· Registered
2002 330ci-5HP-19, 2004 325ci-M56
Joined
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39 Posts
Discussion Starter · #19 ·
Your Scanner is showing the pre-cat O2's as mA values around zero mA. Both are cycling correctly.

Even though the engine was not up to full operating temp, the total fuel trims (STFT + LTFT) for both banks are showing around 20%. This indicated a problem.

The MAF value was in pounds/minute and not grams/second, so I have no idea if the MAF value is correct. Your 325CI should be drawing around 2.9 to 3.4 g/s at hot idle.

Read your first post again.
Whenever you clear the codes, it clears the monitors as well.

Running the required drive cycle usually brings the monitors back into "ready".

Suggested next step is to smoke test the engine and find the vacuum leaks that are causing the total fuel trims to be around 20%. Read: How to Smoke Test
here is a video of the fuel trims when engine is at operating temperature. i noticed when the engine is cold both of the STFT is in normal range but both LTFT is 10.9. when engine is warmed up both of the STFT drops closer to 0 and both LTFT rises past 15. also noticed when i rapidly increased rpm the STFT dropped to -20 for a quick second and returned to normal.

 
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