Subaru Forester 2.0d XC (58) Euro 4 DPF Problem

[AndyW1966]

2 weeks ago I got a flashing DPF light which according to the manual suggests a visit to my Subaru dealer. However, my local mechanic advised on a 20min trip up the M-way in 4th gear to see if light cleared. It did. Approximately 50 miles covered and the flashing DPF light reappeared. I followed same procedure (20min trip up M-way in 4th gear) and the light cleared. Another 50 miles later and the flashing DPF light returned. I covered over 150 miles after this third appearance and emulated previous attempts to clear the light but to no avail. Then, 10 miles (after a trip of around 200 miles)from home the flashing light vanished.

 

Today I took the vehicle to my Subaru dealer. The diagnostics threw a P1468 Oil Dilution code - with no other codes and no other engine codes. The dealer has made a number of checks, applied PAK update from JP3F530A (old) to JP3F541A (new), changed the oil (C3) and oil filter, then reset the oil dilution. Ash is reported at 13% and Soot is reported at 62%. Vehicle mileage is 83k.

 

The engineer then took the vehicle for a test drive on M-way to find the vehicle "trying to regenerate all the time", noting "oil dilution going up" and "estimated distance coming down too fast".

 

My Subaru dealer is recommending a new DPF and new sensors in DPF at circa £2,500, advising that the problem appears to be a failing DPF.

 

I would be grateful for any advice on the subject, i.e. do the symptoms described above necessarily point to a failing DPF? And if so, rather than replace the DPF, does anyone have any advice on getting it professionally cleaned by a company such as Ceramex (http://www.ceramex.com), and indeed would cleaning be likely to solve the problem?

 

Regards,

 

AndyW

 

 

[stants]

Depending on if you know a finely mot tester you could always get it mapped out, as far as I'm aware the mot check is just visual so as long as it looks like it's in place you should be ok

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[AndyW1966]

Thanks for the reply. This is an option and it would also allow me to take the vehicle to my local mechanic for regular servicing as I wouldn't need the SSMIII at the dealer to reset the oil dilution count each time!!

I've since done a bit more digging and discovered that the previous owner only covered 1,000 miles in a six month period prior to me acquiring the vehicle. This suggests lots of short trips and potentially lots of failed/partial DPF regenerations causing the oil dilution to increase and the oil dilution count to increase. Although the oil dilution count is only an estimate by the ECU and not a scientific measure, I suspect that the oil dilution was nowhere near 10%.

I'll stick to the Subaru Forester recommended "driving style" and see how things unfold in next few weeks/months. I'm not convinced of a fault with the DPF as suggested by my Subaru dealer. Surely at 62% soot and 13% ash there's plenty of life left in it, and if the vehicle is failing to perform passive regenerations it points to something else, perhaps; sensors, injectors, EGR, etc. and not the DPF chamber itself?

Andy

[stants]

I'm not really clued up on diesels to be honest, if anything goes wrong with the van I send it to Ford.

I have heard that loads of short trips will play havoc with dpf though, have you tried sticking it in 2nd or 3rd and giving it a welly ?

My dad's diesel mondeo used to try and purge everything at full beans, leaving a massive soot cloud. After you could repeat the run and it wouldn't produce anything out the rear.

As for the dealer & ssm2 software you can get a free version off the web to use with an odb2 adaptor cable,

Have a read through this http://www.subaruoutback.org/forums/65-parts-accessories-performance/39426-freessm-complete-access-your-ecm-tcu.html#/forumsite/20514/topics/39426

Good bit of kit

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[Rizmo]

Lots of DPF problems on the Kia forums, but only for those who do low mileage or short trips. Diesels might give good mpg, but really mile munchers, not shopping cars. My diesel C4 worked fine, when I was working, but after retirement, with just shopping trips, it soon started to mess about - and that was with the Citroen eloys oil pumped into the tank each fill-up. When I bought the Kia, the salesman almost insisted I buy petrol!! Now have the XV petrol, for the same reason. If your DPF is blocked, even slightly, it will be a pig to clear, and a forced regen by the dealer seems not to be an option in your case. Sounds like a new DPF or removing it are the only options.

[Mr B]

Best DPF cleaner I found was my steam cleaner. DPF's are awful bits of engineering, Subarus control setup on the diesels is also not the best but hopefully improving for sake of Subarus reliability image :-S . for most peoples annual mileage a diesel is not very advantageous as fuel savings are equally spent on expensive servicing & problems.

[AndyW1966]

Thanks for the replies - much appreciated. I'll probably get a copy of FreeSSM (cheers Stants!). It will allow me to monitor the DPF, oil dilution, etc., although doesn't allow oil dilution reset - however I may have tracked down some code for this :-)

Cheers,

Andy

[AndyW1966]

My frustration continues - potentially two issues and I'm wondering whether there's a correlation?

 

Firstly the DPF issue. Having returned from Subaru dealer after oil and filter change (due to oil dilution @ 10%) and being told that I need a new DPF due to the fact that the vehicle appears to be constantly trying to do DPF regenerations and Oil Dilution Ratio is rising too fast whilst Estimated Distance to Oil Change is coming down too quickly, I took the vehicle up the M-Way yesterday - a 45 minute trip at >2,500 RPM in 4th gear at a constant 70mph to check if DPF could successfully regenerate. I didn't notice anything (except a decrease in the fuel tank!!).

 

Secondly a MISFIRING issue (?). A few weeks ago I was getting heavy surges/jerks when putting my foot to the floor in 5th gear. My local mechanic suspected a sooted-up EGR valve and possibly dirty injectors. My mechanic cleaned the EGR and injectors but didn't report "excessive soot". On my drive back from the DPF test yesterday I hit a dual carriageway and decided to test the vehicle on heavy acceleration - bearing in mind the engine was pretty warm by now after the M-Way journey. I got huge jolts/jerks when putting my foot to the floor in 2nd gear and 3rd gear. Having read a number of forum threads I am suspecting a faulty O2 (front) sensor.

 

So, I have today hooked up Free SSM and checked the values for my DPF. Reported as:-

 

DPF

Cumulative Ash Ratio = 13% (same as dealer report)

Soot Accumulation Ratio = 47% (15% less than dealer reported)

Running Distance Since Last (DPF) Regeneration Count = 1,137km or 706 miles (appears high and seems to confirm that the vehicle is currently incapable of DPF regeneration)

Oil Dilution Ratio = 2% (bearing in mind I had an oil/filter change last week and only done 120 miles since!)

Estimated Distance to Oil Change = 11,900km or 7,389 miles

 

Mass Air Flow (at idle) = 12.58

 

There are no DTC codes recorded.

 

So, my question is......could the MISFIRING and surge issues under heavy acceleration due to a (potentially) faulty O2 (front) sensor be connected to the inability for the vehicle to perform a DPF regeneration, i.e. incorrect air/fuel mixture and poor combustion?

 

I would really appreciate some expert advice on the issue - it could be the difference between spending £200 (replacement O2 sensors) compared with £2,500 (replacement DPF)!!

 

Any thoughts out there?? Thanks in anticipation.

 

Andy

[stants]

Cam you check the 02 values on the ssm ?

Not really sure to be honest I wouldn't have thought the O2 sensor would be going funny after only a few years,

Just out of interest what fuel are you putting in ?

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[AndyW1966]

Hi Stants.

 

Thanks for quick reply. No - sadly, cannot check O2 values on FreeSSM. Consensus on other forums is that O2 sensors have a life span of around 100,000 miles (mine's at 83,000 miles - so I guess it's feasible).

 

Currently using Texaco Diesel BS EN 590. Do you suggest an alternative?

 

Andy

[stants]

They normally tend to run better on vpower or tesco ultimate. Don'Don'tvask me why but they tend not to agree with bp or texaco as much ?

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[AndyW1966]

Thanks Stants. I'll give those alternatives a try. Cheers!

[stants]

Just a thought you may be able to test 02 sensor values with a muliltimeter.

If it is dead give import car parts a try as they are loads cheaper than dealer for oem parts, I got a new denso 02 last year for 70 quid cheaper than subaru

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[AndyW1966]

Thanks again Stants. I'm new to the Forester and all advice gratefully received. Love the car and the drive, but just frustrated by the niggles since buying 2 months ago. One of the things that encouraged me to buy the car was the "7 dealer service stamps".....make of that what you will :-)

[AndyW1966]

Okay, so six months on from reporting the initial problems, I have been closely monitoring DPF performance using Free SSM. There are no problems with the DPF nor regenerations. Everything appears to be functioning properly with regular soot "burn offs" during normal driving and full regenerations occurring as and when required on longer motorway journeys. However I still have the "surging" issue, which I am now convinced is NOT related to the DPF.

The "surging" issue is really frustrating as it occurs intermittently. Sometimes the car drives like a dream but other times the problem is really apparent. There appears to be no rhyme or reason to it - there seems to be no correlation between fuel fill-ups, quality of fuel, whether engine is warm or cold, etc.

The main symptoms are when driving in 4th, 5th or 6th gear (occasionally experienced in 2nd or 3rd) but more prevalent in higher gears. Under hard acceleration in 4th, 5th or 6th gear, i.e. pushing accelerator quickly to the floor (for example when overtaking a slow-moving vehicle on a rural road), the car jerks ryhthmically at first and if I keep the pressure on the accelerator pedal, i.e. Pedal to the metal, the car begins to jerk progressively more violently (serious misfiring effect without any 'explosions' being heard), so much so that I'm forced to ease off the accelerator. If I try again, the problem persists, i.e. Once I experience the vehicle doing this the problem seems to be there for the rest of the journey. If however I build up speed more gradually I can usually get to a situation where accelerator pedal is pushed to floor and there is no hesitation or "misfiring". The frustrating thng is that the ca may drive perfectly later in the day.

I've trawled the internet forums to try to find other instances of this being experienced by other drivers, but to-date no experiences fully match those that I'm having. There are suggestions that problem could be sensor (O2), malfunctioning fuel pump, dirty fuel filter, coil issues, injector problems, etc. I even pursued idea that it may be the knock sensor....to later discover that the car doesn't have a knock sensor!! I just don't know where to start to try to resolve the problem most cost effectively.

Any advice/recommendations gratefully received!!

Thanks, Andy.

 

[Rizmo]

That sounds very much like a problem experienced by some Kia owners, where the tank lining is coming off, and clogging the fuel filter, which is in the tank. It is easy to change the filter, but Kia have admitted a problem, and are replacing fuel tanks on any affected car, whether in or out of warranty, and with any service history. Whilst yours may not be losing its lining, the low mileage history may mean there is sludge in your tank, which is being sucked into the fuel delivery system, when you put your foot down. The Sportage owners usually only experience their problem on overtaking or steep hill climbing, with heavy throttle. I know it is a pain to remove the Forester tank (the Kia filter is bolted into the top of the tank, and easy to access), it might be worth a check.

[AndyW1966]

Thanks Rizmo. This best matches the problem I'm having. I'll get my mechanic to take a look at the potential sludge issue in diesel tank as first option.

Cheers, Andy.

[AndyW1966]

Okay, after some deliberation I finally got around to having my Forester problem analysed. Courtesy of Paddy at Dales (Subaru), who I would highly recommend, the problem was diagnosed as faulty injectors. Unfortunately, to diagnose this the injectors had to be removed, which in the Boxer Diesel variant means the removal of the engine - which was around £1,000 in labour to start with!!

The injectors were analysed and 3 out of 4 were failing. Already in for £1,000, I chose to have all 4 replaced - initially quoted £569+VAT per injector. Paddy did manage to get Subaru to reduce the price.

Coupled with some additional work to get the car through its MoT, and a new Air-Con Compressor to fix a long-standing air conditioning malfunction, the total bill was circa £4,000 including VAT. Not cheap and an expense I could have done without right now. On the plus side, the car drives like new. When I asked Paddy about potential reasons for the injector failure and any preventative measures that ought to be taken, he did stress that the use of supermarket fuels are deemed detrimental as they contain approximately 5% bio-diesel which is a big no-no for this vehice model. Thankfully, I was aware of this and due to my location I only use branded (Texaco) fuel which doesn't contain bio-diesel. However, I suspect that the previous owner used cheaper supermarket fuel. So, going forward I should be fine. Anyhow, for completeness on this thread I thought it was worth providing details of the outcome, which I hope is beneficial to others.

Andy

[Jay762]

Thanks for the update - particularly useful info confirming the use of fuel that doesn't contain bio diesel with the Subaru diesel lump

[Mr B]

modern diesels are over sensitive junk .

Price to fix some of the Subaru diesel issues are scary for average owner & means for many the diesel has little or no real economy advantage over the petrol.