E220 CDI DPF issue

[propertynigel]

Morning all,

I would be grateful of your expertise or experience please. I collected my E220 CDI four days ago and am very pleased with it. It is a 2012 model and has covered almost 84k. Yesterday, while pulling onto a motorway, the Engine Management Light came on luckily only a junction way from home and I managed to get the car home. I think it was in limp mode as there was no real power.

A friend plugged it into their diagnostics machine and the result came back that the filter was blocked and needed a regen. After reading several articles on the web last night and a previous similar article on here, I have been out in the car this morning in sport mode, high revs and have driven just over 40 miles. Unfortunately to no avail as the mgmt light is still on and the car still has no real power.

What would anyone's suggestions be to remedy this?

All help appreciated, thanks

 

[jc651]

Apart from the DPF being full was there any fault codes for sensors because if there is that's the cause of the DPF problem. Any problems with the sensors will stop a Regen happening so you won't be able to clear the DPF or do a regen.

 

[propertynigel]

Hi JC and thank you for your reply. there were no other fault codes at all, just the one which said that the DPF was blocked. I only picked it up on Thursday last so I'm going to call the dealer in the morning.

 

[geoffus]

Did your friend clear the fault code ?
I have read you need more than half a tank before a regen will take place, not sure if that’s correct though.
My last regen that I monitored took place after just a few miles without high revs, so it may be a sensor that’s preventing it.

 

[kendog91]

Hi JC and thank you for your reply. there were no other fault codes at all, just the one which said that the DPF was blocked. I only picked it up on Thursday last so I'm going to call the dealer in the morning.

I had the same issue when I bought mine, hopefully you got a warranty which should cover it. A dpf clean and a good boot at 70mph for at least 30 mins should do the trick.

 

[kendog91]

The dpf clean will be covered by warranty if you have one.

 

[MrGreedy]

A DPF regen will start on some cars only when about about 20% fuel in the tank. It doesn't need to be anywhere near half full, but that would be plenty.

A DPF regen will only start if all engine and sensor parameters are correct. If they correct parameters are not met, then an active DPF regen will not occur.
In Mercs, DPF regens seem to activate approximately every 400-800 miles, and last for approximately 5-15 miles, depending on control factors I don't understand.

It's possible (likely?) that your DPF is getting full because it's not even doing a DPF regen.

You can tell if it's doing a regen by monitoring exhaust temperature near the DPF, or by installing an LED to show you if the rear heated screen is being activated (which can be tapped temporarily into the rear SAM).

Post #21 and #40 are of particular use for the above two items, but there's good information throughout the thread.

DPF Regen - Install in-cabin indicator light | Engine

Nervously resurrecting this thread. So I've still been thinking about this, and I want to test the rear heated screen as an option for taking the 12v feed for the DPF notification LED (if indeed the rear screen even activates during regen for the W212). I was hoping to use my iCarsoft pro...

forums.mbclub.co.uk

If I were to guess what most likely has happened here is that:
(i) there is something wrong preventing DPF regen, and the trader/dealer has known this. Rather than painstakingly track the fault and sort it, they have done a forced regen to clear the DPF and has got rid of the car ASAP before the DPF fills again; or,
(ii) the DPF is actually at the end of its life, and a new DPF will need to be fitted.

If it's (i) above, it will need to be sorted ASAP.
Common reasons for a DPF regen not activating are too low engine temperature e.g. thermostat too cool, and it should read rock solid 90°C on your dash all day every day, or a faulty engine temperature sensor, so the car thinks it's not up to temperature. There are many other reasons it might not be activating. I strongly suggest a well-trusted independent Merc specialist to look at this.

If it's (ii) above, make absolutely sure it's not (i) causing it.

In any event, this is clearly a pre-existing fault. The supplying garage should be sorting it.
If you get any hint that they are going to try and fob you off or can't diagnose and fix this specialist issue quickly and correctly, you might want to consider rejecting the car. This should be straightforward in the first 30 days of ownership.

Good luck OP and keep us updated

 

[propertynigel]

Did your friend clear the fault code ?
I have read you need more than half a tank before a regen will take place, not sure if that’s correct though.
My last regen that I monitored took place after just a few miles without high revs, so it may be a sensor that’s preventing it.

My friend did clear the code but it the management light came back on whilst I was on a dual carriageway doing about 65, by that time I had been driving for about 30 minutes although not constantly at high speed. there was over half a tank of diesel in at the time. I think your sensor idea sounds likely. I have spoken to the dealer this morning and he has arranged for me to take it to the garage he uses. Thank you for your reply.

 

[propertynigel]

The dpf clean will be covered by warranty if you have one.

the warranty does not cover dpf issues by the looks of it but having spoken to the dealer, he has said that he doesn't expect me to sort it after only having it a few days and he's getting it sorted for me. I just need to take it to the garage today. Thanks for your reply.

 

[propertynigel]

A DPF regen will start on some cars only when about about 20% fuel in the tank. It doesn't need to be anywhere near half full, but that would be plenty.

A DPF regen will only start if all engine and sensor parameters are correct. If they correct parameters are not met, then an active DPF regen will not occur.
In Mercs, DPF regens seem to activate approximately every 400-800 miles, and last for approximately 5-15 miles, depending on control factors I don't understand.

It's possible (likely?) that your DPF is getting full because it's not even doing a DPF regen.

You can tell if it's doing a regen by monitoring exhaust temperature near the DPF, or by installing an LED to show you if the rear heated screen is being activated (which can be tapped temporarily into the rear SAM).

Post #21 and #40 are of particular use for the above two items, but there's good information throughout the thread.

DPF Regen - Install in-cabin indicator light | Engine

Nervously resurrecting this thread. So I've still been thinking about this, and I want to test the rear heated screen as an option for taking the 12v feed for the DPF notification LED (if indeed the rear screen even activates during regen for the W212). I was hoping to use my iCarsoft pro...

forums.mbclub.co.uk

If I were to guess what most likely has happened here is that:
(i) there is something wrong preventing DPF regen, and the trader/dealer has known this. Rather than painstakingly track the fault and sort it, they have done a forced regen to clear the DPF and has got rid of the car ASAP before the DPF fills again; or,
(ii) the DPF is actually at the end of its life, and a new DPF will need to be fitted.

If it's (i) above, it will need to be sorted ASAP.
Common reasons for a DPF regen not activating are too low engine temperature e.g. thermostat too cool, and it should read rock solid 90°C on your dash all day every day, or a faulty engine temperature sensor, so the car thinks it's not up to temperature. There are many other reasons it might not be activating. I strongly suggest a well-trusted independent Merc specialist to look at this.

If it's (ii) above, make absolutely sure it's not (i) causing it.

In any event, this is clearly a pre-existing fault. The supplying garage should be sorting it.
If you get any hint that they are going to try and fob you off or can't diagnose and fix this specialist issue quickly and correctly, you might want to consider rejecting the car. This should be straightforward in the first 30 days of ownership.

Good luck OP and keep us updated

Wow Mr G, thats a lot of information, for which thank you very much. Hopefully the dealer will sort it, he seems a really decent guy and a friend recommended I go there so I'm sure he will keep his word. I really appreciate your response. I'll let you know how it goes.

 

[propertynigel]

A small update, the dealer was mortified when I spoke to him this morning and immediately said he didn't expect me to have to deal with the warranty company hen I'd only had the car such a short space of time, he asked me to take the car to the garage he uses for servicing and repairs. They saw me this afternoon and are having the car in on Friday to get it sorted out. He has given them authorisation to do whatever is needed to make sure that the problem is resolved. Thank you so much for all of your advice and help. greatly appreciated. I hope I am able to be of help to others as time goes on. take care all.

 

[kendog91]

A small update, the dealer was mortified when I spoke to him this morning and immediately said he didn't expect me to have to deal with the warranty company hen I'd only had the car such a short space of time, he asked me to take the car to the garage he uses for servicing and repairs. They saw me this afternoon and are having the car in on Friday to get it sorted out. He has given them authorisation to do whatever is needed to make sure that the problem is resolved. Thank you so much for all of your advice and help. greatly appreciated. I hope I am able to be of help to others as time goes on. take care all.

Glad you was able to get it sorted.

 

[MrGreedy]

the warranty does not cover dpf issues by the looks of it but having spoken to the dealer, he has said that he doesn't expect me to sort it after only having it a few days and he's getting it sorted for me. I just need to take it to the garage today. Thanks for your reply.

Just another point.
A warranty of 6 months or less is only there to protect the dealer/trader. It is not there to protect you.
In simplified essence, if you buy a car from a trader and it develops/there was a pre-existing fault, then it is the trader's responsibility to sort it within a 6 month window. Regardless of any warranty.
To repeat, a sub-6 month warranty is there to protect the dealer.

Totally related, but also can apply separately, the trader might try to fob you off within the 6 month period (longer if buying new) and might be able to say without lying, that XYZ particular fault is 'is not covered by the warranty'. DPF in this instance.
Which might be true. But it is also purposefully and highly misleading; it is leaving out the bit where the trader is still on the hook to get it sorted, in the hope that the customer is naïve and will either go away or pay for it themselves.
With a car very close to sale, your position is ultra strong (remembering you can reject the car without reason within 30 days) because it is highly unlikely that the fault was not pre-existing (DPF full in this instance), and obviously weaker as you get closer to 6 months, as it then becomes a bit more difficult/subjective to agree if the fault was pre-existing.

 

[W1ghty]

Just another point.
A warranty of 6 months or less is only there to protect the dealer/trader. It is not there to protect you.
In simplified essence, if you buy a car from a trader and it develops/there was a pre-existing fault, then it is the trader's responsibility to sort it within a 6 month window. Regardless of any warranty.
To repeat, a sub-6 month warranty is there to protect the dealer.

Totally related, but also can apply separately, the trader might try to fob you off within the 6 month period (longer if buying new) and might be able to say without lying, that XYZ particular fault is 'is not covered by the warranty'. DPF in this instance.
Which might be true. But it is also purposefully and highly misleading; it is leaving out the bit where the trader is still on the hook to get it sorted, in the hope that the customer is naïve and will either go away or pay for it themselves.
With a car very close to sale, your position is ultra strong (remembering you can reject the car without reason within 30 days) because it is highly unlikely that the fault was not pre-existing (DPF full in this instance), and obviously weaker as you get closer to 6 months, as it then becomes a bit more difficult/subjective to agree if the fault was pre-existing.

Excellent advice there buddy