Unreliable: DPF Filter light on - limp mode - sick of this

[Whitey]

I'm sick of this. For the first 200,000kms never an issue, driving around town. Supposedly the DPF filter light/ engine limp mode were fixed 3-4 months ago, yet ever since every 2 weeks the DPF filter comes on and i have to drive 30 mins up a highway to clear it.

This time i choose to ignore it, planning on doing it tomorrow. Bang !! - Limp mode activated with engine light on. Here we go again, will the MM dealer have as much problem forcing a regen as the last time?

How much should it cost to get the regen. done again?

To my mind this is an unreliable aspect of MM Pajero's - does anyone agree ?

I opened a thread 9 months ago here: http://www2.pajeroclub.com.au/forum/...ad.php?t=48464

There's a parallel thread here: http://www2.pajeroclub.com.au/forum/...ad.php?t=51635 for someone stuck near Tennant Creek

UPDATE: For those wanting to skip 15 pages, and one year of pain and $$'s , you can go straight to the "fix" here. You'll never guess what it was : https://www2.pajeroclub.com.au/forum...=51643&page=15
UPDATE 2 It didn't last long. DPF light is on again.

[DaveE66]

Get rid of the dpf. Mine has been off since I bought my ns at 65000 now on 234000. No issues.

[Ian Johnston]

Thats why I bought a manual. No DPF.

[Eastie]

A dealer can check almost everything on the mutt, so don't bother trying to check dpf/cat sensors or the like, leave it to them to do a full rundown. If the oil isn't high &/or wrong spec, I'd be asking them to consider injectors. An NS with a leaking injector or two (suspect with those km's) is a recipe for pdf problems (even with a delete pipe).

[Whitey]

I seem to be answering on one thread, and asking on another - so sorry we kinda have parallel threads.

I thought this article handled it real well:

Frequent diesel particulate filter regeneration or DPF warning light illuminating frequently.

Possible DPF fault or could relate to the type of use the vehicle is subjected to. DPF equipped vehicles typically must be driven regularly at higher speeds to allow regeneration to occur. Vehicles that spend all their time at city speeds may have ongoing issues that result in the need for a manually initiated regeneration. This is not necessarily a vehicle fault and may relate to the vehicle’s suitability for that type of use. See our fact sheet on Diesel Particulate Filters for more information. [ see below link / quote ]

For some engines equipped with a Common Rail diesel injection system the correct engine oil grade is vital. The use of the wrong oil can produce all sorts of performance problems.

http://www.racq.com.au/cars-and-driving/cars/owning-and-maintaining-a-car/car-maintenance/diesel-injector-cleaning

How does it occur?

On-board regeneration is usually completed automatically, often without the driver
even being aware it is occurring. However some operational situations can affect the
regeneration process.

• Low speed and stop-start driving can prevent the initiation or
completion of the regeneration process. In such cases the vehicle
may need to be driven a certain distance at a defined minimum speed
(usually about 80km/h), or alternatively, returned to a dealer to have
the regeneration process manually initiated.

Malfunction Warning

Vehicles fitted with a DPF will have a dash mounted malfunction warning lamp. The
operation of this light varies from make to make and owners should familiarise
themselves with its operation and what it signifies for their particular vehicle.

• The malfunction warning light must not be ignored. Doing so may
jeopardise the continued reliability of the vehicle.

DPF systems and the exhaust system of DPF equipped vehicles in general must
not be tampered with or modified due to the risk of triggering a ‘runaway’ or
‘uncontrolled’ regeneration event. Such events may cause extensive heat damage to
the vehicle and its surroundings.

http://www.racq.com.au/-/media/pdf/r...20filters.ashx

[Whitey]

Picked the car up from the MM service center. The invoice/report said:

Carried out investigation regarding carrying out the forced regeneration.
Traced oil level too high for vehicle to carry out regeneration.
Dropped oil out and replaced, carried out a forced regeneration and all tested ok

I spoke with the MM mechanic afterwards, and he told me that rule of thumb is not to switch the motor off in the midst of a burn/DPF light on. Allow the temperature to rise and complete the burn [ and do not park on grass as it may catch on fire with the high temp].

He said, that the fuel needs to be pumped in, and if it is interrupted, then it will seep into the oil, raising it's level and contamination, preventing the regeneration from occurring.

I'm sure some better folks here can explain this more technical/ accurate terms, but for the first time in 210,000kms i now understand how to drive the car around town and let the burn complete. Fingers crossed i don't trip the error/engine light again.


I hope this and other contributions here help anyone else experiencing problems with the DPF light on.

[Ian Sharpe]

what a crock of a setup, why does this crap have to be foistered on consumers, yeah I know , environment or whatever. Guess you should be thankful it doesnt need that adblue crap. Diesel cars are on borrowed time, anyway. So are petrols, roll on Tesla!

[gta1898]

I spoke with the MM mechanic afterwards, and he told me that rule of thumb is not to switch the motor off in the midst of a burn/DPF light on. Allow the temperature to rise and complete the burn [ and do not park on grass as it may catch on fire with the high temp].

He said, that the fuel needs to be pumped in, and if it is interrupted, then it will seep into the oil, raising it's level and contamination, preventing the regeneration from occurring.

I'm sure some better folks here can explain this more technical/ accurate terms, but for the first time in 210,000kms i now understand how to drive the car around town and let the burn complete. Fingers crossed i don't trip the error/engine light again.


I hope this and other contributions here help anyone else experiencing problems with the DPF light on.

Just out of interest how do you know the car is doing a burn?

Here in the UK DPFs are standard from 2008 ish on all diesel vehicles and I only know when my Pajero (Shogun UK) is doing a burn as I monitor the Cat temp on my Torque app. The DPF and its associated burns is the main reason for getting this app, so when I see a burn happening I can do my best to ensure it completes it, carry on driving for a few miles if necessary to allow it to complete.
If it does initiate a burn and I can't carry on driving, (like a dead end road recently!!)I leave the engine running until the car has shut the process down in a controlled way.

My oil level has never increased due to diesel dilution.

The dash DPF light on UK Pajero's only lights when the car really needs to initiate a burn or in a very short time limp home mode will be the order of the day. Even when it does light there is nothing to tell the driver the burn is actually happening, certain conditions need to be met, engine normal temp, speed above about 40km/h etc , you only know if it's been successful if it goes out.

Another point to remember is as the car ages the DPF fills up with ash that doesn't burn off and thus its capacity to hold soot reduces, so burns may need to happen more often.

My advice get the torque app, this great forum and posts really helped me, and you will be properly informed, it's really worth the small investment.

Hope my points help others too.

[Whitey]

Just out of interest how do you know the car is doing a burn?

For me? - only if the DPF light comes on

[gta1898]

For me? - only if the DPF light comes on

Yes - just be aware as I mentioned above, when the light is on it doesn't mean it's actually doing a burn only that it needs to have one done, so then it's upto the driver to ensure the car is driven in a way that meets the requirements so a burn can happen.

[Stoneman]

One of your temp sensors are crook.

[Sam Pato]

I've never seen the DPF light in about 6 months or ownership either.

Is the comment about temp sensors that I/we are not seeing the DPF light because a temp sensor is crook?

Cheers


Sam

[Eastie]

Having owned one of these since 2007 what I've found is the dpf light will only come on if the system fails to regenerate normally, warning the driver that they need to drive at the recommended 40kmh or more for a duration of 15+ minutes (guessing from memory - typically it's more like 5-10 minutes) or until the dpf light goes out. If the dpf light doesn't go out after driving per the recommendation in the vehicle manual, go to a dealer or plug in your code reader and see what the problem is. Continuing to drive around with the dpf light illuminated continually after doing this (e.g. there's been a problem with the dpf burn cycle) tyically results in CEL and limp mode.

It's all in the vehicle manual.

[Stoneman]

If your light is regularly coming on there is something wrong.
A temp sensor does not necessarily just fail. What ever the problem is you need a mut to diagnose it properly.

A lot of people and am assuming most never see it come on

It always surprises me how complicated this problem can be made

[ryv]

I never saw it come on until the thing pooped itself and almost killed my last Simpson Desert trip. I'm with you Stoneman about the complexity of it. Nightmare...