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PCM Detection condition for P044100
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Steve Smith
- Pico Staff Member
- Posts: 1587
- Joined: Sun Aug 25, 2013 7:22 am
PCM Detection condition for P044100
Hello can anybody help/advise.
I am a firm believer that “nothing is simple” and whilst the rectification for this vehicle was reasonably straight forward, the logic behind the PCM’s fault detection has me baffled.
I have recently been working with an EVAP system of a:
2012 Seat Ibiza 1.2 TSI Ecomotive
Engine Code CBZB
Manual Transmission
Long story very short, fault code “P044100 Fuel Evaporation System Flow Rate Faulty” was stored due to an internal leak within the Evaporative Loss Solenoid
I believe this is known as N80 in VAG Technical Literature.
Basically N80 was stuck open so always venting the Fuel Tank Charcoal Filter to the intake manifold. (No external leakage)
With N80 and pipework replaced, the fault has cleared.
From an electrical point of view the old N80 was fine with the correct resistance, current flow, induced voltage, and duty control. (New N80 compared with old)
The duty control of the old N80 during the typical 1400 to 1500 rpm rev range was also correct when fault code “P044100 Fuel Evaporation System Flow Rate Faulty” appeared.
I.e. this fault code was always accompanied with Freeze Frame data informing of engine speed at approx. 1400 to 1500 rpm!
If you disconnect N80, DTC P044300 would appear referring to N80 circuit and not flow rate. Therefore the PCM can not only detect N80 circuit errors (easy to understand) but also flow rate errors through N80 (not so easy to understand)
So here is my question, how does this engine management system determine the flow rate through N80 when electrically, N80 is fine?
My first thoughts were MAP, MAF & O2 sensor response during N80 operation, but as you can see below, neither MAP nor MAF respond with any relevance when N80 is energised or de-energised.
The response from the O2 sensor was also inconclusive during N80 operation
In a nut shell I am bemused and baffled as I cannot find any “Monitoring” or “Detection” conditions in the Repair Manual or SEAT SSP’s for this fault code.
The image below utilises a WPS500 pressure transducer located between the new N80 and the throttle body. Here the WPS500 detects the effect on manifold pressure during N80 operation (unlike MAF & MAP) but I assume this is because the WPS is better positioned to detect these pressure pulses than both the MAP & MAF sensors
How does this engine management system (Simos 10) know the evaporative loss flow rate is incorrect via N80?
Any feedback would be most help full and put my mind to rest.
Take care……Steve
I am a firm believer that “nothing is simple” and whilst the rectification for this vehicle was reasonably straight forward, the logic behind the PCM’s fault detection has me baffled.
I have recently been working with an EVAP system of a:
2012 Seat Ibiza 1.2 TSI Ecomotive
Engine Code CBZB
Manual Transmission
Long story very short, fault code “P044100 Fuel Evaporation System Flow Rate Faulty” was stored due to an internal leak within the Evaporative Loss Solenoid
I believe this is known as N80 in VAG Technical Literature.
Basically N80 was stuck open so always venting the Fuel Tank Charcoal Filter to the intake manifold. (No external leakage)
With N80 and pipework replaced, the fault has cleared.
From an electrical point of view the old N80 was fine with the correct resistance, current flow, induced voltage, and duty control. (New N80 compared with old)
The duty control of the old N80 during the typical 1400 to 1500 rpm rev range was also correct when fault code “P044100 Fuel Evaporation System Flow Rate Faulty” appeared.
I.e. this fault code was always accompanied with Freeze Frame data informing of engine speed at approx. 1400 to 1500 rpm!
If you disconnect N80, DTC P044300 would appear referring to N80 circuit and not flow rate. Therefore the PCM can not only detect N80 circuit errors (easy to understand) but also flow rate errors through N80 (not so easy to understand)
So here is my question, how does this engine management system determine the flow rate through N80 when electrically, N80 is fine?
My first thoughts were MAP, MAF & O2 sensor response during N80 operation, but as you can see below, neither MAP nor MAF respond with any relevance when N80 is energised or de-energised.
The response from the O2 sensor was also inconclusive during N80 operation
- New N80
The image below utilises a WPS500 pressure transducer located between the new N80 and the throttle body. Here the WPS500 detects the effect on manifold pressure during N80 operation (unlike MAF & MAP) but I assume this is because the WPS is better positioned to detect these pressure pulses than both the MAP & MAF sensors
- New N80 with WPS
Any feedback would be most help full and put my mind to rest.
Take care……Steve
- Attachments
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- TEST 5 NEW VALVE ALL SPEEDS MAP AND MAF.psdata
- New N80 with MAF & MAP
- (21 MiB) Downloaded 643 times
Re: PCM Detection condition for P044100
I don’t have access to wiring diagrams, maybe this car has a fuel tank pressure sensor?
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KimAndersen
- TwoWaves
- Posts: 249
- Joined: Fri Nov 30, 2012 2:53 pm
- Location: Denmark
Re: PCM Detection condition for P044100
Hi Steve
I have some information regarding the diagnostic trouble code P0441 which is not the same as yours P044100 - I dont know the meaning of the last two zeros in this DTC.
Well before you get al too excited with this info here - which I think you should use as a overall guideline as this document dosen´t match your vehicle at all.
Of all the documents that I´ve been reading about the Evap Purge Valve is the main malfunction criteria lambda deviation and idle speed control, so these value can change depending of the vehicle and engine code.
You were looking at the values from the oxygen sensor - maybe you should look at this sensor again to see if there are any changes in the lambda values.
There are also some secondary parameters to consider when your are faced with a DTC like this.
I hope this is of some help.
Regards
Kim
I have some information regarding the diagnostic trouble code P0441 which is not the same as yours P044100 - I dont know the meaning of the last two zeros in this DTC.
Well before you get al too excited with this info here - which I think you should use as a overall guideline as this document dosen´t match your vehicle at all.
Of all the documents that I´ve been reading about the Evap Purge Valve is the main malfunction criteria lambda deviation and idle speed control, so these value can change depending of the vehicle and engine code.
You were looking at the values from the oxygen sensor - maybe you should look at this sensor again to see if there are any changes in the lambda values.
There are also some secondary parameters to consider when your are faced with a DTC like this.
I hope this is of some help.
Regards
Kim
Re: PCM Detection condition for P044100
Hello,KimAndersen wrote: P044100 - I dont know the meaning of the last two zeros in this DTC.
Regards
Kim
The last two zero in the fault codes means -fault is present,10 at the end of fault code means-sporadic error.
In ELSA I can't find any pressure sensor on evap purge circuit,I think it was not used in the last 10 years for detect the leaks,the purge control based on changes in the short fuel trim was introduced.
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Technician
- TwoWaves
- Posts: 707
- Joined: Thu Apr 24, 2014 8:32 pm
Re: PCM Detection condition for P044100
I wonder if it monitors the flow rate from the use of the EGR ?
I don't know but has that vehicle got a secondary air-injection system and would that have an influence?
How much fuel was in the tank during testing?
I'm to understand that the EVAP monitor does not run unless the fuel tank has between 15 and 85% fuel present!
I don't know but has that vehicle got a secondary air-injection system and would that have an influence?
How much fuel was in the tank during testing?
I'm to understand that the EVAP monitor does not run unless the fuel tank has between 15 and 85% fuel present!
Re: PCM Detection condition for P044100
Hi,
If I remember right from technical training all of them work the same. Using a/f sensor for monitoring. If it is lean condition Ecu regulates pwm to n80. if that continues it starts adding fuel via injectors.
If I remember right from technical training all of them work the same. Using a/f sensor for monitoring. If it is lean condition Ecu regulates pwm to n80. if that continues it starts adding fuel via injectors.
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Steve Smith
- Pico Staff Member
- Posts: 1587
- Joined: Sun Aug 25, 2013 7:22 am
Re: PCM Detection condition for P044100
Hello and thank you so much.
We live and learn together for sure
I will get back onto this vehicle next week and monitor Lambda / O2 response in conjunction with idle control in far more detail
I will post the findings here and hope to conclude how flow is detected
Fantastic info that has me fired up for sure
Take care......Steve
We live and learn together for sure
I will get back onto this vehicle next week and monitor Lambda / O2 response in conjunction with idle control in far more detail
I will post the findings here and hope to conclude how flow is detected
Fantastic info that has me fired up for sure
Take care......Steve
-
Steve Smith
- Pico Staff Member
- Posts: 1587
- Joined: Sun Aug 25, 2013 7:22 am
Re: PCM Detection condition for P044100
Thank you again for the interest and now for some feedback
Once again there is another awesome VAG SSP 231 (EOBD) that has some essential information surrounding the detection of EVAP flow
In a nutshell the PCM is looking for a response from the Broadband Lambda sensor (Pre-Cat) relative to the operation of N80.
Using the Lambda sensor also allows the PCM to determine the density of HC stored in the Charcoal Canister based on “rich” feedback for a saturated charcoal filter and “lean” for an empty charcoal filter.
The introduction of HC via N80 will also impact upon short term fuel trim and therefore, mixture correction via injector duration will be implemented simultaneously
This presents a double edged sword from a diagnostic point of view as I was looking for a dramatic response from the Lambda sensor as soon as N80 operates…..how wrong I was!
Over and above Lambda sensor feedback during N80 operation we have the MAP sensor which is alleged to provide feedback on the modulation of N80 during “defined intervals”.
Again I have revisited this measurement and could not truly relate N80 operation to MAP sensor feedback!
The screen shot below will help clarify the above.
Thinking this through we therefore have a number of those dreaded variables working against us whilst trying to prove EVAP flow.
The text above refers to “Cyclic Checks” and the “Slight opening and closing of N80 at defined intervals”
I guess the question here is what does that mean?
What conditions are required for Cyclic Checks?
How do you define the “slight opening and closing” of N80? (10% Negative duty, 20% etc.)
The answers may well be in the “Enabling Criteria” that allow the PCM to run the EVAP Monitor legislated for OBDII.
For example, Evap flow measurement may only be applied under specific engine/road speeds, engine temperatures and loads over a number of key cycles!
N.B. The freeze frame data for this fault code always indicated an engine speed of approx. 1400 rpm
As though that wasn’t enough, how do we know the HC density of the fumes released from the charcoal filter? We expect the operation of N80 to introduce a momentary rich or lean condition but modern emission systems are so responsive when it comes to fuel trimming errors that the opening of N80 will most certainly be met with an instant response from the PCM where by fuelling amendments will compensate.
This all sounds like a “cop out” but here is what I discovered today.
Using Deep Measure topic17711.html to plot each individual negative duty pulse of N80, we can detect the precise opening event of the EVAP solenoid, the progression of opening (as the negative duty increases) and the progressive or instantaneous closure (as negative duty decreases)
The above capture identifies the EVAP cycle 57 as the last open event before cycle 58 where N80 is then closed. (No purge) This is met with a response from the Lambda sensor approx. 106 ms after the close event (which falls within a typical response time of a broadband Lambda sensor)
N.B. Here we are measuring the Pump Cell voltage as per Franks video: https://www.youtube.com/watch?v=UdbZfXMMTQs&vl=en-GB
The fall in the pump cell voltage suggests a momentary enrichment that could be from the closure of N80 that was purging low density HC fumes from charcoal canister or it could be the commencement of fuelling after over run fuel cut.
Note how there is very little (if any) response from the MAP sensor
Here is another incident where I clamped the EVAP pipe leading from the fuel tank to the N80 solenoid and then removed the clamp at approx.1.6 seconds into buffer 21. (N80 Duty was fixed at 14%)
Again the Lambda sensor indicates momentary enrichment as the clamp is removed from the EVAP pipe and HC laden fumes enter the intake manifold.
Finally, I could kick myself here as I may have stumbled across the PCM performing a Cyclic Check but at the time I had the EVAP pipe clamped and so no response from the Lambda sensor!
The Lambda response you can see (Red Channel B) is fuelling corrections under idle conditions, not N80 operation as the EVAP pipe from the fuel tank to the N80 solenoid is clamped.
With hind sight I really need to road test this vehicle with PicoScope attached after determining the EVAP flow “Enabling Criteria”
I guess what we can say is that EVAP flow and HC density of the fumes within the charcoal canister can all be detected via the Lambda sensor.
It is certainly far from conclusive here that we can capture the “flow measurement” event at idle in the workshop but like I mentioned at the start of this post “nothing is simple”
I hope this helps, take care……Steve
Once again there is another awesome VAG SSP 231 (EOBD) that has some essential information surrounding the detection of EVAP flow
In a nutshell the PCM is looking for a response from the Broadband Lambda sensor (Pre-Cat) relative to the operation of N80.
Using the Lambda sensor also allows the PCM to determine the density of HC stored in the Charcoal Canister based on “rich” feedback for a saturated charcoal filter and “lean” for an empty charcoal filter.
The introduction of HC via N80 will also impact upon short term fuel trim and therefore, mixture correction via injector duration will be implemented simultaneously
This presents a double edged sword from a diagnostic point of view as I was looking for a dramatic response from the Lambda sensor as soon as N80 operates…..how wrong I was!
Over and above Lambda sensor feedback during N80 operation we have the MAP sensor which is alleged to provide feedback on the modulation of N80 during “defined intervals”.
Again I have revisited this measurement and could not truly relate N80 operation to MAP sensor feedback!
The screen shot below will help clarify the above.
- EVAP Flow description
The text above refers to “Cyclic Checks” and the “Slight opening and closing of N80 at defined intervals”
I guess the question here is what does that mean?
What conditions are required for Cyclic Checks?
How do you define the “slight opening and closing” of N80? (10% Negative duty, 20% etc.)
The answers may well be in the “Enabling Criteria” that allow the PCM to run the EVAP Monitor legislated for OBDII.
For example, Evap flow measurement may only be applied under specific engine/road speeds, engine temperatures and loads over a number of key cycles!
N.B. The freeze frame data for this fault code always indicated an engine speed of approx. 1400 rpm
As though that wasn’t enough, how do we know the HC density of the fumes released from the charcoal filter? We expect the operation of N80 to introduce a momentary rich or lean condition but modern emission systems are so responsive when it comes to fuel trimming errors that the opening of N80 will most certainly be met with an instant response from the PCM where by fuelling amendments will compensate.
This all sounds like a “cop out” but here is what I discovered today.
Using Deep Measure topic17711.html to plot each individual negative duty pulse of N80, we can detect the precise opening event of the EVAP solenoid, the progression of opening (as the negative duty increases) and the progressive or instantaneous closure (as negative duty decreases)
- N80 On to Off
N.B. Here we are measuring the Pump Cell voltage as per Franks video: https://www.youtube.com/watch?v=UdbZfXMMTQs&vl=en-GB
The fall in the pump cell voltage suggests a momentary enrichment that could be from the closure of N80 that was purging low density HC fumes from charcoal canister or it could be the commencement of fuelling after over run fuel cut.
Note how there is very little (if any) response from the MAP sensor
Here is another incident where I clamped the EVAP pipe leading from the fuel tank to the N80 solenoid and then removed the clamp at approx.1.6 seconds into buffer 21. (N80 Duty was fixed at 14%)
- Evap clamp released
Finally, I could kick myself here as I may have stumbled across the PCM performing a Cyclic Check but at the time I had the EVAP pipe clamped and so no response from the Lambda sensor!
- Possible Cyclic check
With hind sight I really need to road test this vehicle with PicoScope attached after determining the EVAP flow “Enabling Criteria”
I guess what we can say is that EVAP flow and HC density of the fumes within the charcoal canister can all be detected via the Lambda sensor.
It is certainly far from conclusive here that we can capture the “flow measurement” event at idle in the workshop but like I mentioned at the start of this post “nothing is simple”
I hope this helps, take care……Steve