2011 automatic diesel - cutting out and loss of power

[Cdavies25]

Hi there,

I have a 2011 plate diesel smart for two passion, automatic. I got it in Sept 2015, used approved with 27,000 miles on the clock. Since then I have done around 10,000 extra miles in it. It has been running fine until about 2 weeks ago. I stopped at a roundabout and when trying to move off it went into limp mode, the system maintenance light came on and it was going about 5mph before it completely cut out. The same happened again yesterday when I stopped to let a car pull out. I put my foot down flat to move off and I just couldn't get it to power up. I stopped for a bit, tried again and managed to get it up to 30mph but it wouldn't go any faster. It feels like it has no power when I move off and is lagging way more than usual which is making me nervous to drive.

I'm not car techy in the slightest - could someone please tell me what this problem might be in laymans terms? Apologies if this thread is in the wrong place or has gone before. I would just really appreciate it if someone could point me in the right direction. I'm fearful of taking it back to Mercedes as it's on a PCP plan and I've had bad experiences of them previously with them trying to rip me off. I'm hoping my local garage can resolve it.

Thank you in advance.

[10:45PM]

Post 2010 the diesel smart was 'updated' to euro5 emissions spec.

This added several more sensors and a DPF.
These sensors are prone to causing your precise symptoms.

On top of that the DPF is prone to clogging causing power loss, unless you give it an Italian service fairly frequently depending on your style of normal driving and usual journey distances.

Where are you so we can direct you to someone who can fix it?

[Cdavies25]

Hi

Thank you for your quick reply. I had a feeling it might be the sensors. I'm in the West Midlands - Stourport on Severn, Worcestershire. I originally got it from the Birmingham Mercedes dealership. Thanks again.

[lalli_d1]

Post 2010 the diesel smart was 'updated' to euro5 emissions spec.

On top of that the DPF is prone to clogging causing power loss, unless you give it an Italian service fairly frequently depending on your style of normal driving and usual journey distances.

there is no need to give a diesel with a DPF an Italian service'. drive it how it should be driven and the DPF will never clog up. drive it at 70 in top gear, on the motorway for about 30 min in 1 direction will be enough to clear the filter. there is no need to rag the nuts of it to clear the DPF, the ECU will adjust its parameters to allow regen to take place.

the amount of people who say drive it at high revs at 70 have no idea how a DPF regen works... its even written in the hand book how to carry out a regen!

[10:45PM]

Naw, it's still well worth thrashing a diesel within an inch of it's life from time to time, DPF or not..
(I fully understand how a regen works thanks)

There are too many diesel chuggers out there trying to hypermile at 500rpm all the freaking time .... get in and use it !!

Birmingham have a good rep I think? , although you'll be paying full whack for it... the various sensors (if needed) aren't cheap anyway.

[lalli_d1]

why then does it not state in the handbook (of ANY car) to sit at 70 at high revs?

this is an extract out of a Jaguar XE owners manual

DIESEL PARTICULATE FILTER (DPF)
When a DPF message is displayed, accompanied by an amber warning lamp, the filter requires a regeneration cycle to clean itself. This requires the engine to have reached normal operating temperature. Regeneration takes place automatically at an interval of approximately 300-900 km (190-560 miles), depending on driving conditions. Regeneration normally takes 10-20 minutes and is automatically requested by the engine control module if the vehicle is driven steadily at vehicle speeds between 60 km/h to 112 km/h (40 mph to 70 mph). It is possible that the regeneration process will occur at lower vehicle speeds, but the events may take a little longer at a 50 km/h (30 mph) average speed.'

DRIVING SHORT DISTANCES OR IN COLD WEATHER
If the vehicle is frequently driven short distances or in cold weather conditions, then the engine may not reach normal operating temperature. This means that regeneration of the Diesel Particulate Filter (DPF) does not take place and the filter is not efficiently cleaned. When the filter reaches a condition when a filter regeneration is appropriate and the current drive style is not appropriate, a warning triangle on the Instrument panel illuminates and the message DPF Full. See manual is displayed in the Message centre. This is not indicating a fault condition with the vehicle and no dealership support should be required. Start regeneration of the filter by driving the vehicle, preferably on a main road or motorway. The vehicle should then be driven for approximately 20 minutes or more.
When regeneration is complete, the warning text is cleared automatically

no where does it state you need to drive it at high revs!

clearly cdavies was either sold the wrong car or didnt do enough research about new diesel engines!

[10:45PM]

You take owners manuals and life way too seriously Lalli lol

[lalli_d1]

and there is a lot of rubbish that is circulated on forums...

i dont take owners manuals seriously, i know what happens when procedures are ignored with DPF's... i work in the motor trade to know the consequences, time and costs involved to rectify the issues!

i have seen, to may times that sales have sold the customer a diesel when a petrol would have been better. we have even had customers trade there cars in at other dealers for petrols!

customers themselves have even said if i knew my car had a DPF, i wouldnt have bought a diesel.

[Thrumbleux]

why then does it not state in the handbook (of ANY car) to sit at 70 at high revs?!

no where does it state you need to drive it at high revs!!

I'm inclined to agree.
At any constant speed (say 70mph) a certain amount of power is required at the wheels. The wheels care not one jot whether that power is developed at low rpm and high fuelling per cycle in a high gear or high rpm and low fuelling in a low gear. The heat flow through the engine and hence the exhaust is going be pretty much the same in either scenario.