Figure we start a small FAQ page about CPC's and the somewhat mystery behind them and floating questions everyone seems to have, and questions that many should be asking. Nice place to keep important facts and information for current owners and future owners, where we can discuss and share.

I'm sure everyone knows or heard of the lovely names and functions of the CPC, Central powertrain controller, CPC_NG. A Module Mercedes has put in place to perhaps hide, make more difficult, and counter tuning Small square module, Most of the time installed under the kick plate in the passenger side footwell. Think of it as a Parent yelling at their children for the fun to stop, in this case the fun being the Torque and parent being the CPC.
Inside the CPC holds functions like, Torque limits, Speed limiter, Exhaust valve control, Intercooler pump control, fan control, throttle, etc.
Prior AMG's, we had the ECU for the engine and the TCU for the trans. Modern AMG's add the CPC in the mix on top of. Most CPC's are flashed with a new unit, VIN specific from the dealer. Some are flashed at home via OBD wit the new virgin unit installed and oem unit removed. Some bench flash to your vin and specifications, and ship to you ready to install, which is a bit more convenient, I prefer it.


Not all created equal:
Think of a tuned CPC and its TQ limits as a unlock feature for the ECU to do its job to its full potential, to make power and make power properly without being restricted. Unlock it CORRECTLY, you will have the ECU fully doing its job without being restricted and locked down.
Not all CPC's are created equal. CPC's require proper and CORRECT tuning to function and work as ordered to do so. As many may think it is not as simple as a on and off option, this isnt the case, esp when we talk TQ limiters. Many CPC's floating around with the TQ limiters not so removed or adjust as they claim.
Making sure those TQ limits are removed and or adjusted properly within the many maps inside the CPC is where the correct tuning skill and knowledge comes into play. Tq limits by gear and TQ limits via RPM, Main TQ limits, etc. Not adjusting the correct TQ maps correctly and setting them on the 'same page' as each other, and your back at square one with the ECU being limited again.


Know your TQ limits:
It seems many owners, just ask for a tuned CPC and dont know the exact details of what they are getting. They don't know what their TQ settings are set to or their max TQ. I urge us as enthusiasts and owners, ask questions, know what your getting and know what your tunes are set at.
Are your TQ limits completely removed? And they adjusted to be aggressive towards the top end power range and higher gears? Knowledge is power. Removing TQ limits completely with a aggressive ECU tune making alot of power put you at risk of prematurely wearing your clutches, decreased long-term life, reliability and clutch slip with the massive amounts of TQ, and or worse snapping an output shaft. Too little TQ adjustment, and your ECU will continue to struggle to apply a power increase and leave you wondering why. Its your choice of where you would like to be.


Find the right CPC:
Like mentioned earlier, think of the CPC more like a unlock feature for the ECU to run its performance to its full potential or like a parent telling a child "Hey after this amount of TQ the party is over". That's the CPC's most important job, get a proper functioning CPC and the ECU takes over the game from there no matter who tuned the CPC, as long as its done properly. Because of this, Getting a ECU tune and a CPC/TCU from different companies is totally fine because and is a norm in many aftermarket for example the BMW world (TCU's). As long as the CPC is properly tuned to remove or adjust the TQ limits to allow the ECU to work properly to make power. Knowing where your CPC and or TCU is set and tuned for in TQ limits is a important part of the tuning game to setup your car properly.


Intercooler pump control:
100% on full time, or oem variable target control. The M177 LS2 uses 3 electric water pumps in the low temperature circuit and a switch over valve for the trans. These are used to cool, the ECU, 2 intercooler's for the charged air, Heat exchanger for the Transmission and transfer case.
They are variable based pumps that are activated individually based on target temperatures. Depending on the year and model, most of these pumps are made from Continental and Bosch. According to them, they have no testing, life span, and overall performance tests when it comes to FULL time running of the pumps. These types of testing is never done within these companies as OEM's ever demand such requests.
These pumps when they fail or weaken, as some of you may have experienced, MOST never throw error codes. Usually the tell tale sign, that 1, 2, or all 3 pumps have failed or dying, is your trans temp starts to creep high and or begins to overheat since it is tied into the system. Many companies have tuned CPC's for these pumps to run at 100% all the time, for better cooling, especially for the intake charge air, most definitely help with more performance! But it comes with the cost of course of potential Longevity of the pumps. Point here is, many owners don't understand or didn't understand this feature, many didn't choose or make this request, but just a key point to keep in mind when ordering a Tuned CPC in which route suits you best.


NEED a TCU?:
A TCU tune now is less 'needed' than prior gen AMG's esp for the basic tuned owner. Think of a CPC as the first stage of limitation and a TCU as the second stage. Most FBO guys don't NEED a TCU tune. You can unlock enough TQ limits in the CPC, (up to 1000NM+) to snap an output shaft. If you looking for more TQ limits to be removed or want that extra few tenths or need them i.e. have big turbos, a proper TCU tune is a good route to look into to help with trans higher line pressure, fill pressure, clutch clamping force, hold pressure, etc. Remember, the 725.9 MCT is officially rated at 900NM, but many have pushed behind this on stock clutches. The output shaft will only last so long before it twists or snaps depending on TQ values, LC's, miles, etc.


Datalogs:
So a massive importance I always stress falls on datalogs for anyone who is tuned. Want a health check of how the engine is running? boost, ignition, fuel pressure, iats, etc. Datalogs a good general health checkup for your car. Want to see how your car is performing after a modification, or a checkup on if everything is reaching its targets, datalogs.
In certain gears and with certain TQ limits like when you are stock CPC with a tuned ECU, you can see the CPC in action in having the ECU reduce TQ/Load by means of throttle closure, boost reduction and timing.

Here is a W213 E63S with a well known ECU tune, on a stock CPC and TCU. You can see massive throttle closure here (throttle is yellow line), even when the pedal (pedal is purple/grey line) inside the car is at WOT. The ECU is reducing TQ via throttle closure because of the limits in the CPC are being reached. Of course you don't feel this as its done in such a smooth fashion but you may feel the power isn't as increased after a ECU tune as you may have anticipated.





Here is the same car with a 5soko RACE+ tuned CPC added with TQ limits in at the 750 FT LB range. You can see now, when the pedal is WOT (Pedal is yellow line) the throttle also follow and stays open 100% (Throttle is purple line), no throttle closures, no massive TQ reduction, more real world power to the ground.





Another Elephant in the room:

How does the CPC or TCU know your are trigging a TQ limit, does it have a internal dyno? So like most modern ECU's, these ECU's do a internal calculation of TQ using throttle, boost, temperature, timing, etc to output a Engine Torque value it is currently making, and from the factory, this value is pretty accurately setup. The CPC reads this value from the ECU to know if the TQ limits are being surpassed. So what do some tuners do to go around the TQ limits in the stock CPC, they UNDERREPORT the real torque being made in the ECU and trick the CPC. This was common, esp before the CPC/TCU's tune were available.
The tuned ECU with this underreporting will output now a value of say for example 500 FT LBS on a tuned car when in reality its making close to 800FT lbs or more crank, and the CPC sees this value and wont trigger TQ reduction because ECU is below the TQ limit. Problem solved right? Of course not.

To some degree and % underreporting is acceptable without any negative effects for the most part, esp in the short run. Issue lies mostly with the transmission and the TCU. The TCU operates heavily on what the ECU is telling it and one of its main inputs is what 'engine torque' value currently is. The main line pressure of the trans is directly based on the engine torque value the engine says it is making, along with clutch clamping force and other operations. If the ECU torque calculation is telling the TCU it is making 500FT LBS, the TCU will take this value and operate in a 500 FT LB mode per se, with line pressure being such for the given value. But in reality your making MUCH more and your now operating with the wrong pressures. Higher the TQ, higher the line pressure, clamping force, etc.
The effects of a ECU tune NOT 100% reporting accurate TQ: Shifts are not as crisp during partial or WOT, premature wearing of the trans and clutches, micro slippage that you dont feel on every shift and or even in gear during WOT pulls and a bit lazy trans response in general. With a ECU providing 100% accurate TQ, your trans will be able to handle more TQ with the increased line pressure, crisper shifts and longer lasting transmission.

You may ask, How do we know what our tuned ECU is doing? You can always ask your tuner if your ECU is setup correctly for a CPC and TCU tune with NO underreporting, OR you can even check for yourself, its as easy as a datalog and checking the engine torque value, or using Xentry in the Transmission menu, or using sometimes a regular handheld scanner, you can retrieve Engine torque in the ECU data. If during WOT you see very low TQ numbers for your car i.e. 600FT lbs and you know you should probably be making more along the lines of 800+ FT lbs at the engine with your tuned setup, then you know you are most likely underreporting.
The 5soko TCU tune always raises line pressure high to make sure the Clutches will be ready for the increase in TQ and the trans is correctly set so this gives those ECU tuned cars with underreporting some help

I hope this was helpful. I hope to see more datalogs and i hope to see more talk on where everyone has chosen their TQ limits. I always believe the best enthusiast are the educated, well informed and ones who ask questions! Hope this maybe shed some light on how all our control units work and work together and maybe urge us to start asking more questions. I apologize for any typos or corrections needed here. I been wanting to write this for some time now and been piecing it together between work and travel. Also apologize for the long write up!

 

Thank you for writing this. Besides Xentry is there another Datalogger that you would recommend?

 

How important is it to have the same ECU and TCU tuner, or, how important is it to tell the ECU tuner all the stuff the TCU tuner has done?

I already have a Black Boost CPC (uninstalled. I was scared MB would limit sale of blanks so I had one done as soon as I bought the car, just to sit on my shelf collecting dust until factory warranty expires)
I would love the EDOK TCU,
and then have my local tuner Slav at ECC do the ECU tune

For me and my research those are the "best of the best" in each of the three areas CPC TCU ECU

 

Late response here on my end, I just responded in the other thread. If you have HP tuners start there for sure. Will get the basics done, nothing advanced but def better than nothing. LMK if you need any guidance on the channels.

What I try to urge in this thread is the importance of knowledge of seemingly the basics right. Knowing what your TQ limits are set at is a good start for both CPC and TCU. Just for example, getting a CPC that has a 800FT LB limit on it and then later getting a TCU with a 700 FT LB limit on it, can cause a bit of a mess. So know what you have, so you can make the decisions accordingly.

All the CPC and TCU care about for the most part is how accurate and honest the ECU is calculating TQ. The ECU tuner should know, you have a CPC and or a TCU, so he doesn't have to do any underreporting to try to defeat TQ limits within the ECU. Some tuning via the drivetrain CPC/TCU is working a bit better than others and that is where my urge for datalogs come in to see what happening, numbers dont lie.

 

Yes I would love guidance on the channels! Coming from 212 the 213 HP Tuners is missing so much stuff:
https://mbworld.org/forums/w213-amg/...ing-tools.html

 

Awesome writeup and explanation man!

@5soko was extremely helpful back in the day when CPC tuning for W213s was just becoming available, he spent many phone calls with me troubleshooting getting the CPC to work on my car with a few different modules.

 

I have had two different TCU tunes but one cpc tune. I will say mix matching brands of tunes are not a problem but like Soko is saying, knowing the limits and ensuring they are somewhat close will make all the difference.
My better times 10.5@133mph in less than ideal DAs came with a mix match of cpc/TCU/ECU tunes. When I had the same ECU and TCU branded tunes I was a tad slower 10.6/10.7 at about 131/132mph. But the shifts felt like I had a TCU tune. Switching TCU tune made me a tad faster, felt stock but a lot more consistent for sure.

My overall fastest time was with the mix match of tunes (since I never asked questions lol) but ok extremely ideal conditions trapped 136mph

 

I been meaning to do a step by step and breakdown of logging soon for the M157 and M177 as a intro.

W213 is missing a handful of useful parameters, wont be the best, but will get you stared as somewhat of a baseline.
Open HP tuners scanner. Left top click 'open channel config' upload this old channel setup i had attached below.
Traction control fully off, manual mode trans, 3rd or 4th gear, 2K rpm go WOT to redline and shift. Do two of those. This would be a general log.
If you want to go further, another would be a 1-2-3 to see other things like tq limits and boost recovery and timing drop outs between shifts etc.

If you want to graph the log for clearer view and overlays Use https://datazap.me/
In HP tuners, top left, click 'log file' then 'export log file' click export. That file then you can upload on datazap to graph it out.
Report back


The Good days! Thank you for the kind words. You are def the enthusiast this platform needs and deserves! Always curious and always pushing. That is what its all about. Individuals that make the platform's great to be a part of.

Solid times. Sounds like you dont miss the M157 at all

 

Lmao honestly I sometimes I do miss it. With the current understanding of the software on those cars it won't be that difficult to make over 900whp on a w212.
BUT!
Then reality kicks in with scratched cylinder walls, snapped output shafts, etc etc and I quickly get over the itch 😂

 

@kponti It used to be music that separated last and next generations. Now generational differences are found in the other kind of car tunes. I have a stock W213 E63d wagon with more power than I can use safely... had several recent two-lane road passes where, afterwards, I told myself "that wasn't smart" and resolve to back it off even more. It just isn't smart to hit 120 mph passing, even though it's effortless to do so. Simply no margin for the unknown. So I need more power at some unknown risk to the machine? -- Signed, Ol' Fuddy Duddy

 

Great write up. Thanks for taking the time. I have a stage 1 Renntech tune on my 2018 E63 and it runs well. My modification threshold is limited to bolt on or OBD modifications though. I have no plans to break records or swap turbos, install downpipes etc. I asked Renntech what would be the next logical step for a performance increase. They suggested a TCU tune over the CPC. Does that make sense?? For stage 1 cars like mine is one more effective than the other or should they both be programmed?

Thanks!
J.

 

OMG thank you! Saved the xml! Will play around soon.
Thanks again,

 

Not sure why, i would call them in and ask again, make sure its not a miscommunication issue. Renntech is great with communication and their products. As in my write up above, think of it as the CPC being the first stage of limitation of performance, and the TCU being the second stage.

DM me if you need help setting it up and or doing some logs. Like I said, not a depth of info in HP tuners for the M177 but its a baseline of sorts.

Lmao fair fair! M177 LS2 block with its closed deck design, better block casting having almost twice the engine block strength of M157, and the more 'harder' Nanoslide cylinders, its a nice solid package to start.

 

Right there is why I moved up
If the 212 had better cylinder walls and rod design I would have defintely stuck around

 

Hi 5soko thank you for all the great info on the CPC.

currently i am on company X CPC tune, and lets say decide to switch tuner, will the new tuner be able to just flash over the CPC or must I get a new CPC module.

 

Current market, a different tuner will provide you a new CPC unit with their software inside to replace your current CPC unit.

 

Best explanation I've ever seen; great job @5soko .

No I'm beginning to understand how/why Brabus could do so much to the M177 and transmission AND then stand behind their work.

As some say....like divorce, it's expensive because it's worth it.

Thanks

 

It has M157 turbos, Blackboost intake, E40, high flow cats.

Where do I need to go?

Thank you!!

BillWoeb