I recently experienced the “10 start countdown” due to an emissions problem which was diagnosed as the DEF supply line needing replacement along with a DPF cleaning. I haven’t seen this posted as a problem with the GLK and would like some feedback if possible. My engine light has come back on and I’d like to be as informed as possible before I head back to the garage.
Thanks in advance for any input.

 

How was it determined that the DEF supply line is faulty? Have you had the check engine light trouble code(s) read? AutoZone does it for free.

Maybe post the code(s) and we can help more.

 

I have the scan in my vehicle, so I’ll grab it after work and post the codes. The mechanic supplied me with a copy of the scan. One of them was a DEF metering fault which was explained to me over the phone as a “constricted” DEF line which comes in 2 pieces and was almost $1000 here in Canada (dealer only part). I was suspect that that hose would break down that quickly but sometimes you just have to pay when it’s out of your hands?

 

Seems to me that a "metering fault" indicates the metering device, or sprayer/injector is perhaps clogged. The DEF lines themselves shouldn't be restricted by anything.

Looking forward to the code(s).

 

Ok, so here's what the scan turned up................
P13DF00-AdBlue system has a malfunction
P13E300-Number of engine starts is limited due to a malfunction in the AdBlue system
P200200-The efficiency of the particulate filter (cylinder bank 1) is not sufficient
P20B91B- The output for the heating element for pressure line 'AdBlue' has an electrical fault or open circuit
P20B913- same as above
P202E73- Operational fault of component Y129 (AdBlue metering valve)

Any insight/suggestions would be appreciated!

 

OK, now we're talking. The main issue appears to be that the AdBlue metering valve is faulty and that your AdBlue heater (one of them) has an electrical fault, like it burned out or bad wiring.The rest of the codes deal with the effects of these two bad components: it can't run a DPF regen, the number of starts is being limited to "protect" the DPF. Rest assured that your engine and DPF are just fine.

The AdBlue metering valve might be clogged with crystalized urea fluid, thereby preventing accurate spray pattern or no spray at all. There should be a way to check the DEF injector, removing it from the exhaust pipe and cleaning it with hot water to dissolve any crystalization.

The AdBlue heater fault is kind of dicey because there's more than one heater: there's one in the AdBlue tank, where the level sensor and pump is located, and there's at least another one somewhere on the DEF line itself. It might be on the metering valve, like it is on the diesel BMWs, but I'm not sure.

If it's the one in the tank, you're looking at dropping the AdBlue tank, removing the innards which are the pump, level sensor, and heater element and replacing that with a repair kit MB provides. It's a bit pricey but your mechanic should definitively diagnose it before you drop $$$ on parts.

If the heater is integrated into the metering valve, it might just be a quick swap with a new unit or cleaning your existing metering valve. Again, your mechanic should check it to be sure.

Once the defective part(s) are replaced, the system needs to be run through a successful regen. This should reset everything and you'll be on your way.

Hopefully this puts your mechanic on the right track, good luck.

P.S. If all else fails, you can always tune the software to delete AdBlue and not have anymore problems with it. This was the option I chose.

 

Yes, I've looked at that avenue already and it's definitely an option. Thanks for your help. Going into the shop on Tuesday, so I'll let you know how I make out.