DPF Regen - Install in-cabin indicator light

[MrGreedy]

Nervously resurrecting this thread.

So I've still been thinking about this, and I want to test the rear heated screen as an option for taking the 12v feed for the DPF notification LED (if indeed the rear screen even activates during regen for the W212).

I was hoping to use my iCarsoft pro (along with a passenger on a very long journey about to be taken) to view a live data feed for exhaust temperature (it can do this, as can torque as mentioned above) and also have a look at rear window voltage to confirm rear screen activation. But I can't find rear window voltage in iCarsoft (nor incidentally anything around heated seat controls, although I could find those for my recently departed Insignia).

Can anyone offer any advice about where I could tap into the 12v rear heated screen feed?
I know fuse 49 (for the rear heated screen) from the rear SAM is an obvious location. It's 40A, so I'd put a small in-line fuse between location 49 and the feed to the LED, and then take an appropriate earth. I'm sure I can poke a tiny wire through from the boot somewhere and hide it in a discreet location visible in the rear view mirror.

 

[Justintyme]

Hi,

In my rubbish Insignia (soon to go) I've installed a 12v LED wired directly into the driver's heated wing mirror positive and negative wires.

The LED is neatly hidden behind the tweeter speaker grill in the front corner of the door, and lights up blue whenever the heated wing mirror are on. It could easily be positioned anywhere in the door by extending the wires.

The key is that when doing a DPF Regen, the ECU turns on the rear screen and mirrors to put additional load through the alternator and therefore engine, in a bid to increase engine temp. When it does this for a Regen, the LED lights up, but the button on the centre control panel to turn on the demisting is not depressed or lit!

Does anyone know if something similar happens on the w212 E350 Mercs?
I really would like an indicator so I can make sure I keep driving if it's doing a regen so I don't turn the car off and get a load of diesel dumped into the sump and all the associated damage that might do.

Its something that I have often wondered about too...why the manufacturers can't include a warning icon on the dash to indicate when a regen is taking place....would certainly prevent DPF and other damage from incomplete regens.

 

[MrGreedy]

Its something that I have often wondered about too...why the manufacturers can't include a warning icon on the dash to indicate when a regen is taking place....would certainly prevent DPF and other damage from incomplete regens.

They don't include it because 'drivers can't deal with it and will get confused'. And anyway, if you have to go back to the dealers for a £2k DPF replacement, it's because you didn't buy the correct car for your needs/don't know what you're doing/didn't read the manual/didn't follow dash information instructions. So it's your fault as a driver and you deserve it.

What I will say is the number of times the DPF regen has started metres from my house after a hundred+ mile drive in unreal!

 

[clk320x]

Why bother with a DPF regen light? If it was required MB would have fitted it

Just drive your car and forget about the DPF.

 

[MrGreedy]

Why bother with a DPF regen light?

Hah! Because I'm a total engineering nerd!

 

[geoffus]

Hah! Because I'm a total engineering nerd!

That's a perfect answer. I would be interested to see how you get on with this

 

[Tonygw]

I would imagine they dont fit it because its added cost to. Lets be honest all manufacturers are interested these days meeting sales targets, profit and keeping the share holders happy. (oh and not getting caught cheating emmisions LOL)

I would like to see an indicator myself but thats just me...
For now though I just take mine on a decent run once a month as in the current climate I am doing an awful lot of short journeys...

 

[Justintyme]

Why bother with a DPF regen light? If it was required MB would have fitted it

Just drive your car and forget about the DPF.

Sure, just go ahead and forget about it...until it will remind you of its existence, and then see how it goes for you !!! LOL McGreedy called it for what it is. Low engine oil? Warning light. Alternator not charging? Warning light. Nr plate light? Warning light. There are many other items which will trigger warning's / limp mode etc, but a DPF regen in progress? Nada, Zilch. Personally, I would like to know what's happening under the bonnet, and if I can drive on to complete a regen, Fantastic.

 

[Justintyme]

I would imagine they dont fit it because its added cost to. Lets be honest all manufacturers are interested these days meeting sales targets, profit and keeping the share holders happy. (oh and not getting caught cheating emmisions LOL)

I would like to see an indicator myself but thats just me...
For now though I just take mine on a decent run once a month as in the current climate I am doing an awful lot of short journeys...

Yes Tonygw, most people do that ( myself included ) but when I checked the last regen on the Eclass with the iCarsoft OBD reader, it gave the mileage, and I was able to back-track to the exact time it happened. At first I was sure that it had happened on a long 100 mile round trip, which would make sense. But no, it happened on a relatively short trip afterwards of about 10 miles. So yes, I'm all for a regen icon. How many uncompleted regen attempts has it made, I wonder? I check it fairly regularly for soot content and as the level goes up and down, I'm sure that it is regenerating, which is fine,,,but its the failed attempts and any damage that they cause, that worry me.

 

[Deleted member 149005]

Makes sense it will trigger on a short journey when the engine is running sub optimally.

Who misses a proper water temp gauge, a vault meter, a oil temp gauge, an oil pressure gauge, a dip stick....

 

[mersum1es]

I remeber hearing mercedes vans do have DPF light...

 

[Justintyme]

That's a bit ironic,,,as normally, due to Van's being commercial vehicles, you expect them to do mega-miles, and anything doing mega-miles are not normally prone to DPF problems. Its the short trip stop / start vehicles that are prone to the problems.

 

[clk320x]

That's a bit ironic,,,as normally, due to Van's being commercial vehicles, you expect them to do mega-miles, and anything doing mega-miles are not normally prone to DPF problems. Its the short trip stop / start vehicles that are prone to the problems.

True, but if you tend to use your vehicle for short trips then surely a petrol is a better option?

 

[Justintyme]

True, but if you tend to use your vehicle for short trips then surely a petrol is a better option?

Yes, always. Unless you are doing minimum 15-20'000 Miles per year, petrol is the way to go. You need to be doing enough mileage to justify a diesel car. But in answer to the post above, where it was mentioned that some vans are fitted with a DPF Regen warning icon, but vans, because of the nature of what they are used for, should not have any DPF issues., whereas cars who would be the biggest offenders ( for want of a better word,,,) do not have any such warning icon the dash....

 

[rf065]

Yes, always. Unless you are doing minimum 15-20'000 Miles per year, petrol is the way to go.

Maybe a few years ago, modern diesels will now start, stop and re-start DPF re-gen even on short journeys. They no longer require long motorway journeys at "X" amount of revs to complete the regeneration. Given the lockdown, I've just noticed I've only travelled a couple of thousand miles since my service in September last year. Only done very short journeys of a few miles at a time without any faults regarding the DPF.

 

[Stocious]

I think the Dpd idea is a stupid one, plus anyone with mechanical sympathy like me cringe while a forced Regen is taking place, someone somewhere did one and that’s all she wrote,when you have to open bonnets and take care of what’s around your exhaust is daft, emissions control are all afterthoughts

 

[Stocious]

I predict the demise of the Diesel engine in the public transport sector, heavy haulage and industry will continue there use, there’s a lot of money being spent on petrol engine advancement I’ve been paying attention

 

[Mikesmith29]

They don't work unless the rear screen is on.

I have tested this.

 

[MrGreedy]

They don't work unless the rear screen is on.

I have tested this.

Thanks for confirming and I presume you mean the heated mirrors. But as per post #21 and the potential extra issues surrounding temperature auto-activation of mirrors, to avoid this issue with a DPF notification light, I'm just going to tap into the rear screen as the trial location and avoid any mirror related difficulties. A shame, as the notification LED in the drivers door is a very convenient place to put it and was great on the Insignia behind the tweeter grill.

 

[MrGreedy]

A bit of an update.
I have now successfully installed a rear LED that lights when the rear screen has power than can be seen from the rear view mirror (as it was easier than running cabling to the front of the car).

The method I used was as follows, having disconnected the battery and got all the bits out of the boot including the spare wheel and its boot floor cover. Don't shut the boot with the battery disconnected, as it won't open with the key fob (obviously) which will just be added inconvenience. I am not a qualified mechanic or auto electrician; if you choose to have a go at this, you do it at your own risk. There might be errors in what I have written, so if you are not sure, check with someone qualified.

1. Remove the rear lower plastic cover over the boot latch (2 plastic nuts and it pulls off with a tug).
2. Remove the luggage netting mounts in the front of the boot next to the rear seats and down the RHS. This then allows you to;
3. Remove the front plastic boot tray. This then allows you to;
4. Remove the RHS boot liner (there are 3 plastic rivets that prise out and a plastic nut). You can now see the rear SAM.
5. Remove the rear bench and seat back, the airbag C-pillar trims, and remove the two front plastic rivets from the hat shelf (you don't need to remove the two harder to reach rivets right in the corner near the window. Be prepared for a tab to snap off the "AIRBAG" plastic trim pieces; for my black interior the part number for the LHS piece is A2126950130. A good (but quick) video here:

YouTube - Removing s212 rear seats and hat shelf

6. Run some suitable red/black twin 22AWG wire (parts list below) from the rear SAM, following all the existing wires and trunking to get near the RHS rear seatbelt pretensioner wiring. I used auto electrical cloth tape during a lot of this process to secure the wire to the existing loom.
7. Lift the front of the hat shelf and run the wiring under the foam insulation to near the LHS seat belt pretensioner wiring, plus about 2 feet to work with. Secure the wiring under the foam insulation with a couple of small cable ties. Make sure it won't be fouled by the centre seat belt.
8. Run the wiring up the conduit towards the top of the C-pillar, and join the pre-wired LED to the new wire you have installed (red to red, black to black). I soldered the wires together and put slim heat shrink over each joint, and then thicker heat shrink over the lot. Don't forget if you are soldering around the car, put a thick towel down just in case. You could also use crimp no-solder connectors that you heat gun afterwards to seal the connector plastic shroud.
9. Drill an 8mm hole (depends on cap size) through the front of the RHS AIRBAG trim clip, and push in the LED mounting cap (I needed a turn of black tape on it to make sure it was secure).
10. Push the LED through the hole in the RHS C-pillar for the AIRBAG trim clip. Reinstall the C-pillar trim. Put the LED into the cap from the rear of the AIRBAG trim clip and reinstall the clip. Make sure the LED wire is not fouled by the seat belt (otherwise it will rub through the wire).
11. Install a quick acting 5x20mm inline fuse holder on the red wire in the boot (near the SAM).
12. Install a 5A (Red) bullet connector on the very end of the red wire.
13. Remove the 3x 10mm nuts holding in the rear SAM to allow ease of seeing what your doing with the SAM.
14. On the top rear of the SAM is a black rectangular connector with a relatively thick (5mm?) single black lead coming out of it. The connector itself is easily removed by pushing the tab, and has part number 1685450126. It is labelled as plugging into socket 1H on the SAM unit itself. I concluded via groping around under the hat tray, and about 60 minutes of continuity testing with a multimeter that this is the power lead for the rear heated screen. Push the 5A bullet connector into the rear of this black square connector whilst the connector is still connected to the SAM unit. It's a nice snug fit and I can't imagine it falling out. If it does, the LED is fused, and this is the power source for the LED anyway.
15. Loosen one of the earth connection nuts near the same, and crush down the striped, bare metal end of the black wire to achieve a good earth.
16. Reassemble everything, reconnect the battery and test by starting the car and activating the rear heated screen.

Parts list:
12v LED 5mm with cap - £1.49
10 metres red/black twin 22AWG copper wire £3.99
5x20mm quick acting glass fuse with plastic holder 0.2A £2.07
5 amp bullet connector £1.70