2014 CLA - DPF and Running Temp

[David J]

Ok heres the story. 2014 CLA , C200 Cdi. EML came on all codes point to DPF.
I have read that the regeneration will only happen once the engine reaches temp 87.1 degrees, however my car NEVER and I mean NEVER gets to that. Stuck in stop start traffic for over an hour it will occasionally reach 80 but when i start driving it sits back at 60. On a 3 hrs drive cruise control set to 70mph again sits at 60.
I very rarely do short journeys most are 1hr 20min to work and same back on mostly motorway. In the past 10 days Ive done over 3 400+ mile round trips for work 90% motorway.

HELP !

The detective in me thinks its not regenerating cause it never reaches the required temp. Could I be correct? Could it be a dodgy thermostat and changing that would solve all my problems ? What do your guys 1800 cc diesel CLAs run at temp wise? Is the thermostat change a DIY job ?Would changing to premium diesel help? would an additive in the tank help ?

All answers on a post card as its doing my head in.

 

[ph47mf]

doesn't matter whether you are driving on the motorway or stuck in traffic, if you have been driving for a while e.g. 30 minutes plus, the temp should go up to 90c and stay there. it shouldn't go back down. sounds like a faulty thermostat to start with. your driving route says you should be fine and it gives enough time for the car to burn off the soot.

I mean I drive less motorway than you and I haven't had a problem.

How does the car drive now?

get the codes read and go from there.

 

[David J]

Car dives fine - all I do is clear the codes and carry on but its getting annoying - I think I will do the thermostat and go from there.

 

[ph47mf]

it wouldn't hurt just stick a little fuel additive into the tank and give it a long quick drive on the motorway in sport mode (if you have that), i suspect if you use cruise control at 70, the car is still running at below 2k rpm, ideally you want it higher to help your DPF.

 

[David J]

Thanks ph47mf , Im heading Glasgow to Manchester tomorrow so will sit in sport mode - also asked my trusted mechanic of he can do a thermostat change for me this saturday

 

[ashenfie]

I would get the thermostat fixed. The car will drive fine, but not efficiently and further may stop the regen happening (guessing?).

 

[David J]

'My man at the garage' is trying to get a thermostat today and will fit this afternoon if he can get one - local Merc dealers have zero stock so trying to source an aftermarket - will keep you all updated.

 

[David404]

Find a good dual or M way with the engine at normal operating temp cruse at 60-70 (under cruse control ideal) and drop it down a gear or 2 to get the revs up to 2750/3000- cruse for 15/20 minutes.

 

[David J]

Ok time for an update so that my symptoms and hopefully resolution may help others. So car went in for the thermostat change on saturday, that sorted my running temps the car gets up to 80-90 degrees and stays there now. However less than an hour later EML with codes P2459 and P2463, cleared them, done a spirited motorway drive for an hour, went to Tesco, EML back on - cleared - have done approx 200 miles since then, cleared the codes, they keep coming back - usually after the 2nd or 3rd time the car has been switched off. Going back in this afternoon for investigation. Thankfully the car is still under warranty.

 

[David J]

Got my car back today, chap who worked on it was away at MOT station when I went to collect but left word that the fix was software related, something needed reset on the ECU. Does this sound about right ? Could that have been as a result of the thermostat being gubbed and not initiating the regeneration ? Did I read somewhere that on Merc there comes a point where the ECU disables regeneration to protect the car from potential damage due to blocked DPF? Could the software reset have been a re-enable of regeneration, I know I should ask the guy that done the work but don’t want to appear to be a pest. The car seems to be ok now.

 

[David404]

What are the garage using to read the codes, is this a generic code reader or a MB STAR machine? You really need an MB dealer or specialist Indie with a STAR machine to diagnose the fauly.

Fortunatrely you seem to be in a good position if the car is under a warranty but long term you need to develop a relationship with an Indie.

 

[p2djx]

Thought Id provide a further update on this, so after the last repair I got almost 3 weeks before the lights and the same codes appeared again, P2463 and P2459. Notified the supplying garage who have decided not to get the local garage to attempt a 4th repair, they have booked it into the Mercedes dealer a few miles away. The car is getting dropped off later today and a courtesy car provided. I hope Mercedes dont just reset something and clear the codes to get the car back out but rather they actually find and fix the fault. Will keep you all updated.

 

[p2djx]

Just noticed I have 2 usernames - DOH !

 

[Pathfinder]

I was not aware that the engine water temperature determines when DPF needed to be regenerated. How does that work?

Also, Ive never had a car that reached 90c water temp, I would class that as a problem, i.e. overheating, mine rarely goes above 80c, even in a hot summer

 

[p2djx]

I was not aware that the engine water temperature determines when DPF needed to be regenerated. How does that work?

Also, Ive never had a car that reached 90c water temp, I would class that as a problem, i.e. overheating, mine rarely goes above 80c, even in a hot summer

Im unsure as you how correct that is but somewhere on the web I saw it noted that one of the parameters required (amongst others ) for a regeneration was the engine temp to be 87.1 whereas Ive also read other owners say their car regenerated under 60 - the wonders of the web, one question a million different answers. Since having the thermostat rep;laced the car will reach around 89 and sit there - and thats in the recent weather climate in West of Scotland.

 

[p2djx]

Well so far Mercedes have had my car 3 days and no update tick tock

 

[markjay]

I was not aware that the engine water temperature determines when DPF needed to be regenerated. How does that work?

Also, Ive never had a car that reached 90c water temp, I would class that as a problem, i.e. overheating, mine rarely goes above 80c, even in a hot summer

My Mercedes me Adapter Bluetooth App is regularly showing the coolant temp after a long run as 92-93 degrees, engine oil temp the same. The highest I've seen it go was 96 degrees. No idea if the sensor and/or the App are acurate though.

 

[p2djx]

OK so another update. It took Mercedes exactly 7 days to tell my supplying dealer the car was ready. Asked what they had done to resolve my issue - a forced regeneration. Groan . . . . . so I took the keys and said OK see you in a fortnight when the light will be back on. I was a bit generous with that statement as the light came back on 23hrs after collection. So its now going in to the 3rd garage for repair next monday, this is the 5th attempt at repair. As always an update will follow.

 

[ashenfie]

It does rather depend on were about the sensors are too, but ~90c would be normal and if driven hard anything up to 110c would be expected for oil. The water temp. should stay more or less constant.

 

[p2djx]

Latest update is that they think the fan is faulty as the car has started, but never completed a regeneration for quite a few cycles. Anyone experienced this, can confirm or explain further? I know many components get very hot during the regeneration but is the fan linked to a safety cut off I.E in my case the car sees the fan is innop so as a precaution suspends the regeneration as it wont have the correct cooling ?