EM light on, in limp mode - various DPF codes - Help please!

[Jamie KC]

Car is a 2012 2.0 TD, 163ps version, car does 30min commutes daily, but gets a good hooning up some decent hills on the way home with the intention of activating DPF regen.

Set off on Sat AM for the Festival of Power at SP raceway, 50 miles into the the 235 mile journey the EM light came on with an "Engine Malfunction" message. Drove the next 120 miles or so just fine, but then started losing power as it had entered limp mode. The return journey was slow, with a run up at the hills necessary as we started climbing bigger ones on the way back into Cumbria. Into the crawler lane at times as speed dropped away.

Plugged in a bluetooth ELM327 reader today, got a long list of codes. Cleared them down including archived, took it for a drive, and read the codes again. All DPF restriction related, as follows:

P246C

P2463

P246C(00)

P2463(00)

P246B(00)

What can be done aside from replacing the DPF? Are there various things to try? It's my first DPF issue, despite putting over 100,000 miles onto a Galaxy with the 140ps engine.

Many thanks, Jamie.

[TomsFocus]

I'd start with the vaporiser on that engine.

[Jamie KC]

13 hours ago, TomsFocus said:

I'd start with the vaporiser on that engine.

Thanks. What would I do to start with the vaporiser? Excuse my ignorance, there’s a lot of stuff I’m fairly good at with cars, but know little to now’t about the DPF system!

Have seen something relating to code P246C on a Transit, and a blown fuse for a vaporiser being the fix. Don’t know if this translates to being something so simple on these cars?

First chance to really take a look is Thursday, hoping it gets me through two days of commutes til then. 

[TomsFocus]

Checking the fuse isn't a bad start.  Nothing to lose by doing that.  Though at 100k, the vaporiser itself will probably need replacing.

[Jamie KC]

Fuse intact. Vaporiser ordered for this afternoon. Will whack a DPF spray into it while under car as well to help it along. 
Also ordered a FORscan compatible usb lead, will download Forscan so can do a forced regen. 
Thanks for the advice.  🤞🏻

[Jamie KC]

Replaced vaporiser today, had hoped to blow through diesel pipe to see if pressure there or free flowing, but had to destroy it to remove it. Looked likely that it was clogged.  

Emptied a can of JML DPF cleaner into it, 1/2 a can through the temp sensor hole in front of DPF, and half a can into metal pressure sensor pipe in middle of DPF.

Took it for a run, straight into limp mode with EM light on, but carried on the run anyway. 10 mins up and down hills then onto the m/way and 20 mins in 3rd at 60. Can't imagine the temps got high enough in limp mode for a regen though. 

 

Back home, FORscan USB lead arrived. Checked data feed. 

DPF load = 268 %

Soot load = 290 %

Engine coolant temp reaches and exceeds 80deg C

Reset DTCs, nipped up road, EM light and restricted power in 2/3 mile.

Did NOT reset DPF learned soot levels, as a warning came up suggesting if I did this then a forced regen cannot be performed due to potential for dangerously high temps.

 

Read codes, they are:

===PCM DTC P246C:00-AF===
Code: P246C - Particulate Filter Restriction - Forced Limited Power (Bank 1)

===PCM DTC P2463:00-AF===
Code: P2463 - Diesel Particulate Filter - Soot Accumulation

===PCM DTC P246B:00-2F===
Code: P246B - Vehicle Conditions Incorrect for Particulate Filter Regeneration

 

So it seems I can't do an active/dynamic regen. Was hoping to avoid forced as then needs oil change, but may be the only way.

FORscan says:

Diagnostic Trouble Code details

If DTCs P242F and P244B are set, do not perform the diesel particulate filter static regeneration. Investigate these DTCs first.

It is important to determine the root cause of the blocked filter.

Note: The following procedure must be performed exactly as instructed.

Re-program the PCM to the latest level calibration.

Engine Warm Up

Use Datalogger to check the following:

Engine coolant temperature

Engine temperature must reach 80 degrees celsius

Perform the following powertrain service function:

Reset the Diesel Particulate Filter Learned Values

Perform the following powertrain service function:

Diesel Particulate Filter Static Regeneration

Investigate any other DTC that may be present in order to determine the root cause.

This DTC may be caused by :

EGR valve stuck in the open position.

Leakage, blockage or restriction in air intake system.

Air leak in the vacuum hoses between the turbocharger and the air intake throttle.

Blocked or leaking differential pressure sensor hoses.

Differential pressure sensor electrical fault.

Pre-catalyst temperature sensor electrical fault

Post-catalyst temperature sensor electrical fault

[Jamie KC]

Questions:

1 - How critical is immediate oil change after forced regen, one more day of commuting (35 miles) OK before oil change can happen?

2 - FORscan says - Re-program the PCM to the latest level calibration - How is this achieved please?

3 - FORscan directions are:

Perform the following powertrain service function:

Reset the Diesel Particulate Filter Learned Values

Perform the following powertrain service function:

Diesel Particulate Filter Static Regeneration

BUT, when I clicked on reset DPF learned values it warned that static regen should NOT be performed afterwards, so...?

[TomsFocus]

I think there's some confusion with the Forscan wording here.

1. There's no need to do an immediate oil change after a static regen.  On this engine, the use of the vaporiser means there's little to no need for post-injection in the cylinders, which is the only way to get diesel to the DPF on cars without a vaporiser, and the reason that diesel contaminates the oil on those engines.  Definitely check the oil level after a forced regen, but as long as it isn't excessively high, it'll be fine.

2. PCM updates used to be dealership only.  But may now be possible using Forscan with an extended licence.  They take ages though, so you will need a good cable and power to both the car and the laptop while updating the PCM.

3. I wouldn't recommend resetting the learned values unless the DPF had been fully cleaned or replaced.  I think Forscan is saying that it won't let you start a static regen with values so high, so you would have to reset them first to 'fool' it into allowing the static regen.  That seems like a very dodgy method though and not one I'd be keen on.  If the soot level really is that high (not a fault with sensor or pipes) then I'd want to remove it and either clean or replace it myself.

[Jamie KC]

Thanks for taking the time to explain that Tom. 
1 - Good news. Not a fan of oil not doing its job properly. 
2 - will swerve that for now then. Guessing if it fails part way through then drama ensues!

1 hour ago, TomsFocus said:

3. I wouldn't recommend resetting the learned values unless the DPF had been fully cleaned or replaced.  I think Forscan is saying that it won't let you start a static regen with values so high, so you would have to reset them first to 'fool' it into allowing the static regen.  That seems like a very dodgy method though and not one I'd be keen on.  If the soot level really is that high (not a fault with sensor or pipes) then I'd want to remove it and either clean or replace it myself.

I think I may have the two DPF reset types confused. I may have selected reset DPF soot load counter as opposed to DPF learned values, and that is when the warning came up. Perhaps resetting the learned values is not a problem for a static regen as it still knows the soot load?

My laptop is at home but I’ll check the log tonight, see what function I selected and aborted. If it still shows after disconnected…

[TomsFocus]

The problem with resetting the learned values is that the PCM then won't take account of the ash in the DPF.

Ash builds up over time, reducing the amount of space for soot.  This constantly and permanently increases the base level pressure across the DPF.

Resetting the learned values should really only be done after that ash has been cleared out (physically impossible without removal and backflushing) or a new DPF has been fitted, which obviously won't have any ash in it.

I'm not sure about the soot load counter reset, don't remember that one being an option on the ones I had.

[Jamie KC]

16 hours ago, TomsFocus said:

 I'm not sure about the soot load counter reset, don't remember that one being an option on the ones I had.

Think I must’ve been getting that confused with an option I’d seen elsewhere, you’re right, twas learned values only!

16 hours ago, TomsFocus said:

Resetting the learned values should really only be done after that ash has been cleared out (physically impossible without removal and backflushing) or a new DPF has been fitted, which obviously won't have any ash in it.

Any advice on best practice welcomed - Looking online at flushing info the advice is widely varied - water is fine/don’t use water! Oven bake/chemicals/compressed air is needed. and on…

I’ve got a garden hose and a pressure washer, obvs have basic soaps like washing up liquid (seen soap recommended) and pressure washer cleaning liquids.

Big concern seems to be it drying and setting ash in a solid immovable state thus ruining future cleaning and regen opportunities for DPF. So let drip dry off car or put back on to blow through with exhaust and dry that way?

Day off tomorrow and the car is back up on its ghetto ramps, nuts are sprayed ready for DPF removal. 🤞🏻

 

[Jamie KC]

Is “back flushing” meant literally as in flush from rear to front so it comes back out the way it went in, or should it be from both directions?

[TomsFocus]

3 hours ago, Jamie KC said:

Is “back flushing” meant literally as in flush from rear to front so it comes back out the way it went in, or should it be from both directions?

Backflushing is only done from rear to front.  The ash particles are too large to fit through the pores in the DPF core, so they have to come back out the way they came in.

As you've seen, there are many opinions on DPF flushing online!  I sort of meant professional backflushing really, but you're welcome to try it yourself.  Worse case scenario it just has to be replaced anyway.

Yes, you must get all of the ash out once it's wet, otherwise it sets like concrete.  It doesn't matter where it dries as long as all the ash is out first.