E-Class (W212) 2010 - 2016: E 350, E 550
Sponsored by:
Sponsored by: CARiD

M278 MED17 PCM pinout?

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old May 5, 2024 | 12:31 PM
  #1  
Siegmann's Avatar
Thread Starter
Super Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2018
Posts: 961
Likes: 103
10-second E550
M278 MED17 PCM pinout?

I need to check continuity to the ignition coils - does anyone have a PCM pinout? M278 engine.
Reply
Old May 5, 2024 | 01:00 PM
  #2  
Chevota's Avatar
Super Member
20 Year Member
Photogenic
 
Joined: Aug 2004
Posts: 954
Likes: 245
E550 Coupe 2wd (2016)
I have looked many times, but all I find is a few pins used for programming. Power, CAN high/low. And MED17 apparently isnt enough info. From what I found the .1 .3 .7 or whatever there are, can have different pinouts. Can't say the spark pins are different since Ive never seen them, but fyi.
Reply
Old May 5, 2024 | 01:16 PM
  #3  
Siegmann's Avatar
Thread Starter
Super Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2018
Posts: 961
Likes: 103
10-second E550
Originally Posted by Chevota
I have looked many times, but all I find is a few pins used for programming. Power, CAN high/low. And MED17 apparently isnt enough info. From what I found the .1 .3 .7 or whatever there are, can have different pinouts. Can't say the spark pins are different since Ive never seen them, but fyi.
Okay, thanks - it's a MED17.7.1 if that helps whomever has this info.
Reply
Old May 5, 2024 | 03:17 PM
  #4  
Chevota's Avatar
Super Member
20 Year Member
Photogenic
 
Joined: Aug 2004
Posts: 954
Likes: 245
E550 Coupe 2wd (2016)
In my searches this about the best it got, which is useless but fyi. That link is for my ecu, but that website has some info so worth a look:
https://www.evc.de/en/product/bsl/sh....7.3%20Bootpin

The other is MHH Auto, *******.com, which is more of a darkish web forum. Lots of info there, so if it exists, this is where I'd look. I did look and found nothing, but can't say I looked very hard. And to post there you have be a member, which is like $25?
Fk, I figured they'd block it, so ******* dot com
damit! m h h a u t o dot com

If you do find anything, please share!
Reply
Old May 5, 2024 | 05:10 PM
  #5  
Siegmann's Avatar
Thread Starter
Super Member
5 Year Member
Liked
Loved
Community Favorite
 
Joined: Sep 2018
Posts: 961
Likes: 103
10-second E550
I used a multimeter to figure it out. I was hoping to find a broken wire, but the cylinder in question is connected as it should be.

If anyone cares:

Signal from the larger PCM harness to coils (for me... maybe all M278/157, not sure):
Cyl 1: pin 9
Cyl 2: pin 33
Cyl 3: pin 34
Cyl 4: pin 35
Cyl 5: pin 10
Cyl 6: pin 32
Cyl 7: pin 11
Cyl 8: pin 8

Coil connector:
Pin 1: +12V?
Pin 2: ground
Pin 3: ?
Pin 4: signal from PCM
Reply
Old May 5, 2024 | 06:36 PM
  #6  
Chevota's Avatar
Super Member
20 Year Member
Photogenic
 
Joined: Aug 2004
Posts: 954
Likes: 245
E550 Coupe 2wd (2016)
I care! Thanks You can pinout the whole ECU if you like, while I sit on the couch and wait

For future use; I found this link saved as an info source but I can't get in to read anything. I guess you have to sign up now? https://ecuconnections.com/forum It's more above board but it's something.
And this one: http://nefariousmotorsports.com/forum/index.php as the name implies it's more darkish like MHH Auto
Reply
Old May 6, 2024 | 01:35 AM
  #7  
S-Prihadi's Avatar
MBWorld Fanatic!
5 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2018
Posts: 6,600
Likes: 6,547
From: Jakarta-Indonesia
2014 - W212.065 - E400 ( M276.820, 3 liter Turbo) RWD not Hybrid
Siegmann,

Here you go........ M278 ECM N3/10 wiring diagram. 3 sheets. attached as PDF

There are 2 connectors at the ECM, one is M and one is F.
M is engine connector aka ECM to all engine sensor + components. 2 sheets/pages.
F is vehicle connector aka ECM to Front SAM fuse box and some others like radiator fan etc etc. 1 sheet/page.


The COP is a 4 wire version, with built-in driver or electronic switch. So ECM does not need to handle the near 20 amps power surge to COP, that is direct fuses from Front SAM.

The pins you tested in blue and my comment in orange:

Signal from the larger PCM harness to coils (for me... maybe all M278/157, not sure):
Cyl 1: pin 9
Cyl 2: pin 33
Cyl 3: pin 34
Cyl 4: pin 35
Cyl 5: pin 10
Cyl 6: pin 32
Cyl 7: pin 11
Cyl 8: pin 8

Above are the 5 volts trigger to the COP driver

Coil connector:
Pin 1: +12V?
---- Power ground to Z6z1 or z2 harness, which is Main Ground ( negative ) called circuit 31 connector sleeve
Pin 2: ground ---- Signal ground to W11 which is ECM ground
Pin 3: ? --- +12V main positive power. Fuse 23 or Fuse 24 depending on which Bank the COP is at. Per Bank ( 4 COPs ) get 1 fuse.
Pin 4: signal from PCM --- 5V trigger signal for driver


---------------------

See below for the COP pins assignment M278


Your M278



Actually the COP also has a small copper pin which is negative/ground at its body and bolt ring, touching the cylinder head.
The bulk of the near 20 amps power COP required, a lot is handled by that small copper pin and bolt ring.







So what do you want to actually do with the COPs ?
I can help you.

.
Reply

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 10:31 PM.

story-0
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-1
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-2
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-3
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-4
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-5
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-6
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-7
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-8
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE
story-9
10 Most Reliable Mercedes-Benz Models You Can Buy Used

Slideshow: From bulletproof sedans to surprisingly tough SUVs, these Mercedes models proved that the three-pointed star can go the distance.

By Verdad Gallardo | 2026-04-08 09:55:49


VIEW MORE