204 DSG intermittent momentary power loss

[ben3042]

Hi all,
Desperately looking for some assistance!
I have a 2018 204 DSG high line. Had it from 8k miles, now has 82k on the clock. I’ve done all of the servicing and maintenance on it as I’m very mechanically minded and my business is automotive electrical design.
However, I have a fault that I cannot get to the bottom of.
I have VCDS so can take data logs etc.
It’s showing no fault codes.
You can be driving along normally and then suddenly the engine will completely cut power for a quarter of second and then continue fine. I can do a 100 mile trip without it happening, but then it could do it 10 times on a 5 mile trip.
It’s had 1 fault code for a while for EGR insufficient flow but last night I finally got around to changing the EGR valve and cooler and hoped that would solve the cutting issue, but it hasn’t.
I’ve also just given it a full service plus DSG oil and filter, glow plugs and fuel filter.
If anyone can help, it would be most appreciated!! We are going away in it at the end of the month so I really need to get it sorted!

 

[mmi]

Engine ground strap?

Search results for query: earth strap

www.t6forum.com

ECU power supplies - fuses?

CXHA Non start [Resolved]

Hi Guys I have a 2019 T6 here CXHA engine.Was going down the motor way then just bogged out like it ran out of fuel. Now it won’t start I have 350bar of rail pressure fuel up to the filter. I’m getting a cam and crank signal. But it’s like the injectors are not firing. The vehicle will start on...

www.t6forum.com

How does the engine start - immediate start-up always or some cranking before firing up?

 

[Pete C]

When the engine cuts out, what happens to the dashboard instrumentation ? Do the needles twitch or drop ?

Pete

 

[ben3042]

Engine ground strap?

Search results for query: earth strap

www.t6forum.com

ECU power supplies - fuses?

CXHA Non start [Resolved]

Hi Guys I have a 2019 T6 here CXHA engine.Was going down the motor way then just bogged out like it ran out of fuel. Now it won’t start I have 350bar of rail pressure fuel up to the filter. I’m getting a cam and crank signal. But it’s like the injectors are not firing. The vehicle will start on...

www.t6forum.com

How does the engine start - immediate start-up always or some cranking before firing up?

Ground strap is good, fuses all look good. I haven’t inspected the wiring harness around the ECU but it hasn’t been touched around there so can’t imagine it being that, plus the time lag whilst it’s doing it is always exactly the same. I’d expect varying time durations if it was a wire break or loose connection.
It always starts up straight away, even with the stop/start. I’m hoping someone can tell me what channels to log and then have a look at the log file to see what’s going on. It’s such a strange issue!

 

[ben3042]

When the engine cuts out, what happens to the dashboard instrumentation ? Do the needles twitch or drop ?

Pete

Nothing at all, everything is completely normal. It’s just the van jerks for a quarter of a second and the goes again. Makes your heart skip a beat!

 

[JDC]

Could a blocked/ sticky valve on one of the turbos. Or possibly the vanes on the turbo itself. I had similar a while back on another car and went into limp mode. Had to get the turbo refurbed. Been great ever since.

 

[ben3042]

Could a blocked/ sticky valve on one of the turbos. Or possibly the vanes on the turbo itself. I had similar a while back on another car and went into limp mode. Had to get the turbo refurbed. Been great ever since.

I’m fearing this…. But don’t want to start changing parts without a diagnosis if possible!

 

[mmi]

I have VCDS so can take data logs etc.

Please post engine blockmap - preferably engine idling.

VCDS > Applications > Controller Channel Map​

[Single Controller Address - 01]​

[Measuring Values]​

[CSV file]​

The result file blockmap-01-... will be in folder C:\Ross-Tech\VCDS\Logs\...​

Also full VCDS Auto-Scan never hurts.

It’s just the van jerks for a quarter of a second and the goes again.

Is it literally 250 milliseconds?
Are the wipers on when it happens? Just thinking about brake disc drying.
Does it happen with cruise control? Is it adaptive cruise?

 

[ben3042]

Please post engine blockmap - preferably engine idling.

VCDS > Applications > Controller Channel Map​

[Single Controller Address - 01]​

[Measuring Values]​

[CSV file]​

The result file blockmap-01-... will be in folder C:\Ross-Tech\VCDS\Logs\...​

Also full VCDS Auto-Scan never hurts.


Is it literally 250 milliseconds?
Are the wipers on when it happens? Just thinking about brake disc drying.
Does it happen with cruise control? Is it adaptive cruise?

I’ll get the log shortly

Not sure on the exact timing, but it is the same amount of time (by feel/judgement) every time it happens.
No wipers aren’t on, nor have I experienced it with cruise in. It is adaptive yes. But the fault usually occurs during acceleration anyway. I’ll be back shortly with the log

 

[ben3042]

Please post engine blockmap - preferably engine idling.

VCDS > Applications > Controller Channel Map​

[Single Controller Address - 01]​

[Measuring Values]​

[CSV file]​

The result file blockmap-01-... will be in folder C:\Ross-Tech\VCDS\Logs\...​

Also full VCDS Auto-Scan never hurts.


Is it literally 250 milliseconds?
Are the wipers on when it happens? Just thinking about brake disc drying.
Does it happen with cruise control? Is it adaptive cruise?

Auto-scan file attached. having trouble with the blockmap. I run the application and it completes but no file appears in the log folder.... any ideas?

 

[ben3042]

Auto-scan file attached. having trouble with the blockmap. I run the application and it completes but no file appears in the log folder.... any ideas?

Please post engine blockmap - preferably engine idling.

VCDS > Applications > Controller Channel Map​

[Single Controller Address - 01]​

[Measuring Values]​

[CSV file]​

The result file blockmap-01-... will be in folder C:\Ross-Tech\VCDS\Logs\...​

Also full VCDS Auto-Scan never hurts.


Is it literally 250 milliseconds?
Are the wipers on when it happens? Just thinking about brake disc drying.
Does it happen with cruise control? Is it adaptive cruise?

If I tick measuring values and adaptions, the attached file appears

 

[mmi]

I run the application and it completes but no file appears in the log folder.... any ideas?

If I tick measuring values and adaptions, the attached file appears

Unfortunately it's a shortcoming of older generation VCDS cables. They just can't handle properly the T6 engine controller communication protocol. Only VCDS HEX-V2 and HEX-NET-cables can fully handle the protocol. The blockmap would have been a nice and easy snapshot of engine status (about 1500 measurements done in 60 seconds).

Anyways, the cable can log engine data so we should be good.

Spoiler: Note: data logging speed

There is huge difference in data sampling rate between older generation and current VCDS cables. The high speed logging is very useful for catching glitches or rapid changes, e.g. events during engine cranking.

You could try logging the below - please select "Turbo" mode for faster logging.
Basically trying to catch an interrupt in fuel injection or charge pressure build-up. Vehicle speed is included just to give rough idea of power demand.

IDE00021 Engine RPM​

IDE00075 Vehicle speed​

IDE00347 Air mass: actual value​

IDE00351 Main injection: start of activation​

IDE00352 Main injection: duration of activation​

IDE00594 Absolute intake pressure​

IDE00589 Fuel pressure​

IDE04685 Setpoint generation interior torque​

IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value​

IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value​

IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value​

IDE11117-ENG127253 Charge press. ctrl deviation after throttle valve bank 1​

Meanwhile have a read here - perhaps something useful.

Fault code help please

Hi guys I have the fault code as listed below and have changed the sensor but still have the fault code showing after reset. I have no loss of power or any other problems apart from the waring lights. would anybody have an idea of what to try next, Thanks.

www.t6forum.com

 

[ben3042]

Unfortunately it's a shortcoming of older generation VCDS cables. They just can't handle properly the T6 engine controller communication protocol. Only VCDS HEX-V2 and HEX-NET-cables can fully handle the protocol. The blockmap would have been a nice and easy snapshot of engine status (about 1500 measurements done in 60 seconds).

Anyways, the cable can log engine data so we should be good.

Spoiler: Note: data logging speed

There is huge difference in data sampling rate between older generation and current VCDS cables. The high speed logging is very useful for catching glitches or rapid changes, e.g. events during engine cranking.

You could try logging the below - please select "Turbo" mode for faster logging.
Basically trying to catch an interrupt in fuel injection or charge pressure build-up. Vehicle speed is included just to give rough idea of power demand.

IDE00021 Engine RPM​

IDE00075 Vehicle speed​

IDE00347 Air mass: actual value​

IDE00351 Main injection: start of activation​

IDE00352 Main injection: duration of activation​

IDE00594 Absolute intake pressure​

IDE00589 Fuel pressure​

IDE04685 Setpoint generation interior torque​

IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value​

IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value​

IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value​

IDE11117-ENG127253 Charge press. ctrl deviation after throttle valve bank 1​

Meanwhile have a read here - perhaps something useful.

Fault code help please

Hi guys I have the fault code as listed below and have changed the sensor but still have the fault code showing after reset. I have no loss of power or any other problems apart from the waring lights. would anybody have an idea of what to try next, Thanks.

www.t6forum.com

Thankyou for this!!
I have just been out for a drive whilst logging those channels, data attached. It did cut once about 3 minutes in to the run. Hopefully the data shows something useful.... the logging frequency is terrible, even with turbo mode on. So I might need to do more runs to capture it

 

[mmi]

the logging frequency is terrible,

Agreed - a data set of 12 samples in approx. 1.5 seconds. Well, if we just can narrow down the search, we can improve it by logging fewer items. To capture events while logging could use "Marker" button to make a stamp into the log - very useful tool for pinpointing.

It did cut once about 3 minutes in to the run

Possibly the glitch was captured at 200.54 seconds - see a snapshot below - marked with red:

• Revs and speed and revs - vehicle gaining speed.
• Air mass - a lot of air was sucked into engine
• Main injection duration - a lot of fuel was injected
• Fuel pressure - significant pressure build-up
• Intake pressure - turbo boosting at max (sorry about poor channel - this saturates at 255 kPa - actually the pressure can go up to 300 kPa)
• Also significant torque request
• Also good cylinder pressure at first - pretty much the max you can get - not sure if we missed a drop because of logging frequency - see drop in air mass
• The yellow ones indicate foot off the throttle
• 
  
• See the red drop in graph below at 200 seconds
• Possibly missed a drop in charge pressure (either still above saturated 255 kPa, or missed completely because of logging frequency)

Could it be this one - another explanation could be if you were very briefly off the throttle in the middle of the acceleration which just wasn't captured in the log.

Also the operation of bypass valve seems to be different than mine. See the orange (and red) dips below at around 180 and 232 seconds - they went unnoticed because foot was off the throttle.



Well, the behaviour seems to repeat at every acceleration. See below.

I need to try to reproduce the behaviour. I did a recording with same set but didn't see that kind of behaviour at all - perhaps I didn't accelerate hard enough.

---

Updated data set for logging - sorry couldn't reduce the number of values - to keep the track of the conditions during test run.
And a full scale channel for charge pressure.

IDE00021 Engine RPM
IDE00075 Vehicle speed
IDE00347 Air mass: actual value
IDE00352 Main injection: duration of activation
IDE00589 Fuel pressure
IDE04685 Setpoint generation interior torque
IDE07375 Charge pressure before throttle valve: calculated actual value
IDE07736 Turbocharg.2 compress.outlet: press.sensor 1 bank 1: raw value
IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value
IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value
IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value
IDE08138 Bypass valve for turboch 2 turbine inlet: activation

 

[ben3042]

Agreed - a data set of 12 samples in approx. 1.5 seconds. Well, if we just can narrow down the search, we can improve it by logging fewer items. To capture events while logging could use "Marker" button to make a stamp into the log - very useful tool for pinpointing.



Possibly the glitch was captured at 200.54 seconds - see a snapshot below - marked with red:

View attachment 210343

• Revs and speed and revs - vehicle gaining speed.
• Air mass - a lot of air was sucked into engine
• Main injection duration - a lot of fuel was injected
• Fuel pressure - significant pressure build-up
• Intake pressure - turbo boosting at max (sorry about poor channel - this saturates at 255 kPa - actually the pressure can go up to 300 kPa)
• Also significant torque request
• Also good cylinder pressure at first - pretty much the max you can get - not sure if we missed a drop because of logging frequency - see drop in air mass
• The yellow ones indicate foot off the throttle
• 
  
• See the red drop in graph below at 200 seconds
• Possibly missed a drop in charge pressure (either still above saturated 255 kPa, or missed completely because of logging frequency)

Could it be this one - another explanation could be if you were very briefly off the throttle in the middle of the acceleration which just wasn't captured in the log.

Also the operation of bypass valve seems to be different than mine. See the orange (and red) dips below at around 180 and 232 seconds - they went unnoticed because foot was off the throttle.

View attachment 210342

Well, the behaviour seems to repeat at every acceleration. See below.

I need to try to reproduce the behaviour. I did a recording with same set but didn't see that kind of behaviour at all - perhaps I didn't accelerate hard enough.

View attachment 210362

---

Updated data set for logging - sorry couldn't reduce the number of values - to keep the track of the conditions during test run.
And a full scale channel for charge pressure.

IDE00021 Engine RPM
IDE00075 Vehicle speed
IDE00347 Air mass: actual value
IDE00352 Main injection: duration of activation
IDE00589 Fuel pressure
IDE04685 Setpoint generation interior torque
IDE07375 Charge pressure before throttle valve: calculated actual value
IDE07736 Turbocharg.2 compress.outlet: press.sensor 1 bank 1: raw value
IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value
IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value
IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value
IDE08138 Bypass valve for turboch 2 turbine inlet: activation

wow, Thankyou so much for spending the time analysing this mmi!
That behaviour at 200s is more than likely it! I hard accelerated for about 6 seconds with foot down to (but not engaging) kick down. The cutting tends to be more repeatable with harsh accelerations which is why I kept booting it.
I’ll pop out now and get a new log with that data set. Back shortly!

 

[ben3042]

Agreed - a data set of 12 samples in approx. 1.5 seconds. Well, if we just can narrow down the search, we can improve it by logging fewer items. To capture events while logging could use "Marker" button to make a stamp into the log - very useful tool for pinpointing.



Possibly the glitch was captured at 200.54 seconds - see a snapshot below - marked with red:

View attachment 210343

• Revs and speed and revs - vehicle gaining speed.
• Air mass - a lot of air was sucked into engine
• Main injection duration - a lot of fuel was injected
• Fuel pressure - significant pressure build-up
• Intake pressure - turbo boosting at max (sorry about poor channel - this saturates at 255 kPa - actually the pressure can go up to 300 kPa)
• Also significant torque request
• Also good cylinder pressure at first - pretty much the max you can get - not sure if we missed a drop because of logging frequency - see drop in air mass
• The yellow ones indicate foot off the throttle
• 
  
• See the red drop in graph below at 200 seconds
• Possibly missed a drop in charge pressure (either still above saturated 255 kPa, or missed completely because of logging frequency)

Could it be this one - another explanation could be if you were very briefly off the throttle in the middle of the acceleration which just wasn't captured in the log.

Also the operation of bypass valve seems to be different than mine. See the orange (and red) dips below at around 180 and 232 seconds - they went unnoticed because foot was off the throttle.

View attachment 210342

Well, the behaviour seems to repeat at every acceleration. See below.

I need to try to reproduce the behaviour. I did a recording with same set but didn't see that kind of behaviour at all - perhaps I didn't accelerate hard enough.

View attachment 210362

---

Updated data set for logging - sorry couldn't reduce the number of values - to keep the track of the conditions during test run.
And a full scale channel for charge pressure.

IDE00021 Engine RPM
IDE00075 Vehicle speed
IDE00347 Air mass: actual value
IDE00352 Main injection: duration of activation
IDE00589 Fuel pressure
IDE04685 Setpoint generation interior torque
IDE07375 Charge pressure before throttle valve: calculated actual value
IDE07736 Turbocharg.2 compress.outlet: press.sensor 1 bank 1: raw value
IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value
IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value
IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value
IDE08138 Bypass valve for turboch 2 turbine inlet: activation

Log file attached. It glitch 2 or 3 times back to back about 3 minutes before the end of the log. I added a marker within a couple of seconds after it did it. Hopefully this shows something!!
If you think we are going to struggle, I can get a new hex-v2 cable ordered for delivery on Tuesday to give us the increased logging frequency. See what you think to this data set. And thankyou again for your help!!!

 

[mmi]

Thanks. Yes, looks like the same happened before the marker (at 516 seconds).
Not sure if the better sampling rate adds much value any more - certainly would give more fine-grained plots. Of course a good excuse for update. Another benefit would be the capability of making blockmaps - for future reference




PS. The "IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value" wasn't logged. Not a big deal - just a different view into.

 

[ben3042]

Thanks. Yes, looks like the same happened before the marker (at 516 seconds).
Not sure if the better sampling rate adds much value any more - certainly would give more fine-grained plots. Of course a good excuse for update. Another benefit would be the capability of making blockmaps - for future reference

View attachment 210395


PS. The "IDE07742 Cylinder head: pressure sensor 3 bank 1: raw value" wasn't logged. Not a big deal - just a different view into.

Ah dammit sorry I missed that one.
Ok so does this point to the source of the fault to you? I’m not quite sure what to make of it!

 

[mmi]

Ah dammit sorry I missed that one.
Ok so does this point to the source of the fault to you? I’m not quite sure what to make of it!

I'm not sure. I'll do similar runs with mine (same CXEB engine) to get more data. A 30 minute capture today didn't have any of the drop-outs with these - but I didn't push it that much.

IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value​

IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value
IDE08138 Bypass valve for turboch 2 turbine inlet: activation​

 

[ben3042]

I'm not sure. I'll do similar runs with mine (same CXEB engine) to get more data. A 30 minute capture today didn't have any of the drop-outs with these - but I didn't push it that much.

IDE07785 Turbine actuator 1 bank 1: posit.feedback - Actual value​

IDE07793 Turboc.1 turbin.bypass valve 1 B. 1: pos.feedback - Actual value​

IDE08138 Bypass valve for turboch 2 turbine inlet: activation​

Ok Thankyou!
I’ll do another run tomorrow with the other pressure channel logged. I’ll bite the bullet and get a new cable ordered too - looks like mine isn’t working to trigger adaptions either so another excuse to upgrade!