Quite serious problems with my car:
I've had a new aftermarket DPF fitted to my 2007 Seat Leon FR TDI 170 and the DPF light will not go out. It won't regen itself either to put the light out. Garage has essentially given up believing it to be an ECU fault (and that caused the first DPF to clog/die)
A forced regen will put the light out for about 4-5 miles, then comes back and it stays on. It was compared side by side on diagnostics with a Skoda Octavia VRS 170 (same engine), all my car's readings from pressure, soot load etc were apparently quite different.
I am very close to disposing of the car at auction. I have a niggling feeling that the aftermarket DPF may be causing the issues, but can't rule that out without forking out for another!
Can anyone help?
Engine producing lots of smoke for some other reason?
Seems to be a big flaw in all these tales of DPF woe. If something goes wrong with the engine causing it to smoke a lot, how would you know other than the DPF blocking up really quickly?
I'm not a mechanic though, can someone enlighten me?
However in the OP's case, if it started playing up immediately the aftermarket part was fitted, then it's a crap part and demand your money back!
Get the DPF removed, saves a whole shedload of aggro.
Its not yet required for MOT so get rid, get more power and be happy.
DPFs do an important job, I would not want mine removed.
Have the garage confirmed that it's not the pressure sensor?
The pressure sensor went on my 2009 VRS 170 (CR) last year and the symptoms appear to be similar.
There is lots of info online about the pressure sensor in the VRS and I googleguessed the problem before the garage ran the diagnostics.
I replaced the pressure sensor for £200 because I was away from home and needed a working car. In hindsight I should have had the dpf removed to remove the possibility of future issues.
Does no-one give a shit about air pollution then?
I have had loads of problems with aftermarkets CATs in the past, I see no reason why the same shouldn't be for DPF's.
If the car is seeing the DFP as blocked there's three possibles,
1. it's blocked
2. the pressure sensor(s) is(are) faulty so the ecu thinks it's blocked
3. the ecu is knackered
If the aftermarket DFP is too restrictive/poor quality/not doing its job right, the pressure differential reading across it may well be high enough for it to trigger a blocked fault.
If all of the above is OK and the DPF is actually blocking then you have a fueling problem
I will not be deleting the DPF, MoT pass is only one of many potential issues. The others briefly are insurance, tax evasion, VOSA roadside checks and the fact it's illegal. Lets draw a line under that straight away. I will sell the car rather than DPF delete.
The pressure sensor has been changed, along with one of the exhaust temp sensors and air mass meter (which was swapped and made no difference so was swapped back)
The DPF may not actually be clogging up quickly, it could just be that the car thinks it is
Cheers Michael, I replied without seeing your response first.
Regarding 2, from reading VAG service training materials I have found that the car uses the pressure sensor, the 2 temp sensors and the air mass meter to determine the soot load in the DPF. Apparently, if the car gets no signal from one of these, it does regens on number of miles/hours driven basis for a while then throws a MIL fault further down the line. I have found that if the air mass meter is disconnected, my car no longer puts the light on after 4-5 miles saying it is blocked. So I am assuming it has gone into the per miles/hours regen cycle mode.
Regarding 3, if the ECU was knackered would I not see faults elsewhere?
I would imagine it will have two sensors, before and after the dfp - unless the ECU calculates the before pressure. If two, which was replaced?
Is this the same fault that the DPF was replaced? What's the mileage?
I assume the VAG system uses some form of 'special' fluid to enable regeneration. This is normally injected in to the fuel/exhaust - is this system working properly/ Without it the car will not me able to regenerate normally
This happened on my Transporter - cause was a faulty Exhaust Pressure Sensor giving intermittent readings. Maybe get it changed an see if that helps?
I assume the VAG system uses some form of 'special' fluid to enable regeneration
No, no fluid in these afaik.
I would imagine it will have two sensors, before and after the dfp - unless the ECU calculates the before pressure. If two, which was replaced?
It only has one sensor that takes the pressure before and after, it just gives the difference (piezo transducer, if the pressure is higher on one side it bends the opposite way). This has been replaced.
Is this the same fault that the DPF was replaced? What's the mileage?
Mileage is 115k. Car didn't manage to regen the filter on a normally long enough motorway run. It was trying to do it, you can tell as the power dips. Garage couldn't get a forced regen to work either so condemned the filter
I assume the VAG system uses some form of 'special' fluid to enable regeneration. This is normally injected in to the fuel/exhaust - is this system working properly/ Without it the car will not me able to regenerate normally
No eolys fluid on these, it's a combined Cat/DPF unit.
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I think the world is against me, for some reason the tech support line I rang the other day for the DPF manufacturer, React, no longer works! Euro car parts also deny it ever existed!
So at 115k the DPF was probably due to be replaced anyway?
Can you see the Pressure Differential reading in the diagnostic tool?
If so, disconnect the sensor from the exhaust, that way it will see atmospheric pressire on both sides. The ECU should the give a differential pressure of zero. If is giving a reading of greater than zero there is either a wiring fault of the ecu is faulty.
If it gives zero when disconnected but a +ve Dif pressure reading when connected up to the exhaust then the DFP is blocking/has a higher resistance than than it should have.
With a freshly regenerated brand new DPF the Dif pressure reading should be almost zero. If it's not I'd guess the new DFP is faulty/not to VAG spec and this is the cause of your problem.
+1 for pressure sensor. We had a recurring problem with the warning light reappearing in our Octavia Scout a few months after our DPF was replaced under warranty at 80K.
We rang Skoda Assist who sent a tech around to our house and he replaced it there and then for £50 (we paid upfront as it avoided us having to take it into the garage for a warranty fix). He advised that the OEM version of the exhaust pressure sensors was prone to water ingress causing faulty readings.
My Bora was throwing up an "emmissions workshop" message for about a year, would sometimes acrtivate limp mode sometimes not. Noone could find the fault, even when the ECU fried itself, they just pointed at the front end and said the problem was in there somewhere. Refurb'd ECU and a bill less than half what i thought and the issue is resolved.
sounds like a right bind - glad i plumped for the petrol version in the end, although the MPG hurts 🙁
When the pressure sensor was changed were the pipes connected to it blown through to check for blockages? Blow an airline down one at a time and have someone listen at the exhaust pipe, one will be louder than the other.
Was the pressure sensor genuine and have you tried another? We have had a couple faulty from stock.
When the pressure sensor was changed were the pipes connected to it blown through to check for blockages? Blow an airline down one at a time and have someone listen at the exhaust pipe, one will be louder than the other.
They've checked that
Was the pressure sensor genuine and have you tried another? We have had a couple faulty from stock.
Genuine part and I assume it was double checked. Made no difference to error seen and it's been to 2 different garages, Seat and a VAG independent
Can you see the Pressure Differential reading in the diagnostic tool?If so, disconnect the sensor from the exhaust, that way it will see atmospheric pressire on both sides. The ECU should the give a differential pressure of zero. If is giving a reading of greater than zero there is either a wiring fault of the ecu is faulty.
If it gives zero when disconnected but a +ve Dif pressure reading when connected up to the exhaust then the DFP is blocking/has a higher resistance than than it should have.
With a freshly regenerated brand new DPF the Dif pressure reading should be almost zero. If it's not I'd guess the new DFP is faulty/not to VAG spec and this is the cause of your problem.
This makes sense. I will put this to the garage. They probably used similar logic to get to their conclusion that it's ECU/wiring
So if it's been to a Seat dealer and VAG specialist they should have the VAG diag tool so they will be able to do the checks I suggested.
I can see a backlash against diesel cars in a couple of years. Just too many really expensive to repair issues occur on the new ones.
Glad I went petrol this time.
(admittedly a turbocharged and supercharged petrol so possibly negating the 'simplicity factor' somewhat...)
Rachel
Ironically, ten years ago people were banging on about how unreliable hybrids were going to be, and that diesel was a far better option...
My Prius wouldn't turn on properly yesterday, big warning messages on the dash. Checked the voltage on the small 12V boot-up lead-acid battery - 9.8V! Amazed it'd been starting at all...