e55igor1

Hi, everyone!
I have problem with my car, from this forum find out that M156 engine has common problem with intake manifold gasket leak and purge valve. Does anyone know what is wrong with my car or had the same problem? Check engine light is on, P0191, P2187, P0451. Car drives good, powerful, no misfires, only little rough when idling Please help! Thank you

CarHopper

P0191 - Fuel rail pressure sensor circuit range/performance
P0451 - Evap emission control system pressure sensor range/performance
P2187 - System too lean bank 1

It sounds like you have a vacuum leak. I think the MAF's can be stubborn from time to time so I would check for leaks there. I would also look around the fuel pressure regulator (there should be a vacuum line heading to it and that's the one to look for).

--The idling problem, however, is what sounds like a vacuum leak. Especially because it doesn't have a problem once you're past idle which generally points at fuel pressure regulator related leaks.

Just a thought on a place to start

e55igor1

I am guessing too that is the vacuum leak, any other thoughts? Bad sensors? Check engine comes and goes.
Did the first test: Cleared the error codes, started the engine and idling for 5 min. Checked the codes again, no faults.
Second test: driving, after 1 min check engine light, faults again
Seams like accelerating makes difference.....

HoozyerdaddyC63

I had same issue and brought it in to service to get looked at. They replaced the intake manifold gasket and seals all under warranty. Car runs great now.

noodleman

hmm, i've having similar issues. I thought it was just my air filters.

I didn't get the P0191, but i did get:

P2422 evap system vent solenoid valve stuck closed
P0451 - Evap emission control system pressure sensor range/performance
P2187 - System too lean bank 1
and the code for bank 2 too lean.

I already cleared the codes, I'll see if it comes up again, if it does I'll take it to the dealers...

Merc63

Sounds like the valve in the evap system.


I have one if you are out of warranty.

noodleman

i'm still under warrantly, just a hassle to take it in haha.

e55igor1

My car is out of warranty. I planning to spray some MAF cleaner around intake manifold to check where is leak located. Thank you so much for your time and help! Will update if I find out something.

drawde

was the code p3699 or p0191? or are those the same thing?

CarHopper

^same thing. 3699 is mercs way of coding the standard p0191 with the obd2 scanners

e55igor1

Was very simple, just putted back the engine oil deep stick and no more codes and CEL. Thank you to everyone!

Sidv22

do you have an aftermarket tune? I have kept some money on the table for a tune but want to clear my doubts regarding inherent issues

e55igor1

Hello, everyone! I put the engine oil dipstick back and CEL was off for 2 month. Now the light is back with one error code "P0191". The car drives normally, have a lot of power, no shakes or smoke, only annoying "Check Engine Light". Cleared the code 3 times, coming back after second engine start when I am accelerate to highway speed limit. Do you think it is bad sensor? Thank you!

e55igor1

Also, does anyone knows what square black lights on the photo means? not all error codes have them... Thank you!

e55igor1

Finally, I found and resolved the problem with "Check Engine Light". In my case it was bad PCV Valve / Breather hose (part of emission system), part# A156 010 03 70 ($90.00). In regular maintenance routine, it needs to be changed every 70,000 miles.

Maybe this information will be helpful who have similar problem with M156 6.2 engine
Symptoms:
If the faults codes P0191 P2187 P0451 present, CEL is ON, can be white smoke from exhaust after cold start, no misfiring, engine oil around the PCV Valve, engine oil dipstick popping out, part# A156 010 03 70 must be replaced.

In some cases, it can be the Purge Valve, fault code P0444. Check if it pulsing by holding it, you will fill the vibration if it working good.

Thank you everyone for help!!!

Vegas_AMG

Glad you found the problem. Can I please have a little more detail on the purge valve? Location, what to pull to check the pressure, etc. I'm getting the P0171 code but it could be the dipstick like you said maybe I didn't push it down all the way. I'm going to clean my MAF sensors as I have K&Ns but I cleaned them months before the CEL tripped. CEL showed up right after I got the Euro v4 upgrade.
Can't imagine its my PVC valve car only has 26k on the clock.

e55igor1

The purge valve located by drivers headlight, two rubber hoses connected to it. When the engine running, it pulsating if works correct (makes vacuum in the engine).

mb techman

.

e55igor1

Thank you!