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MTU 18V2000 troubleshooting

MTU 18V2000 troubleshooting

MTU 18V2000 troubleshooting

We have MTU engine 18v2000. its MDEC damaged and replaced by new one.
The new one starts the engine, but the speed does not go more 1400rpm, and HZ is 47 only not 50 HZ. the alarm code appeared on ECU is 180 and 187 which mean problem on connection on CAN 1.
We checked mechanically and found all ok.
We checked all wiring and found all ok.
How to troubleshoot the problem?
Your help is highly appreciated.

RE: MTU 18V2000 troubleshooting

I've only worked on one of these, and that was 5 years ago. Remind me - is that CANBUS 2wire?


Harmless flakes working together can unleash an avalanche of destruction

RE: MTU 18V2000 troubleshooting

What damaged the MDEC?

Are all the termination resistors in place for the CAN lines? Some of these units have multiple devices hanging off the CANBus, and lack of one of the devices will cause problems, although that usually means the engine won't start rather than almost running up to speed. Its been a while since I've dealt with the MTU equipment though, and there have been some changes to ECU and associated equipment.

RE: MTU 18V2000 troubleshooting

I had a problem with an electronic governor on a generator that wouldn't come up to speed.
Turned out that the replacement governor was the wrong model.
Check that the replacement is indeed the correct model.

"Why not the best?"
Jimmy Carter

RE: MTU 18V2000 troubleshooting

Usually a Canbus fault indicates CAN High or CAN Low voltage is out of range, or that there is no CAN response to an ECM poll at all. Typically those messages are associated with physical problems in the Canbus, such as wiring or connector problems or improper or missing burden resistors.

So first off, did you follow the units troubleshooting guide? MTU usually has pretty good technical documentation.

In general I find two common issues that cause most Canbus faults on ECM's (pretty much the same for all manufacturers engines I get around) wiring/connector problems and power supply issues (bad grounds, battery problems, alternator problems, etc)

Best way to troubleshoot Canbus issues in my experience is with a scope, however you can do a set of basic checks with a good quality DMM (Digital Multi-Meter) that in my experience will usually find about 90% of wiring and connection related problems. Here are a couple of links you may find helpful,



I've also attached some info from a class I help put on once in a while for technicians dealing with electronic engines, this one is focused on industrial gas engines but it is essentially the same presentation i use for diesel engines as well, you may find it helpful.

Hope that helps, MikeL.

RE: MTU 18V2000 troubleshooting

One more question, did the replacement MDEC get the correct configuration file loaded? An incorrect configuration may also cause the symptoms you are reporting.


RE: MTU 18V2000 troubleshooting

the new mdec is correctly configured by the supplier, thanks to all for your help , I will feedback

RE: MTU 18V2000 troubleshooting

hi all
after thorough checks for all CAN1 CAN2 wiring are in open circuit as the engine was running normal , it 180 AND 187seems AND to me the wiring was not as per the standard an this alarms were canceled on MDEC ? ANY BODY HAS ANY IDEA HOW TO CANCEL ALARMS ERRORS 180 AND 187? or any other recommendation may help?

RE: MTU 18V2000 troubleshooting

Usually on these engines the alarm codes will go away once acknowledged and they are no longer active, not sure what vintage/version you have based on the info provided. Are you reading the codes off a text display from an MDEC control panel? On most I'm familiar with button 6 has a small LED next to it, if LED is on alarm condition is still active, if the LED is off, then pressing button 6 twice should clear the alarm message.

Some units did not have the MDEC display, and only the PIMS display for fault codes, these were usually packages by someone else and in most of the ones I've seen had a Basler Generator Control panel installed.

Since you appear to live in the 50 Hz world and I in the 60 Hz, it is likely you have a package I'm not familiar with. Knowing who packaged it and exactly which version of the 18V2000 you have could get you better answers. After the model number there is usually a four alpha numeric code, like G76F (which is a standby power rated unit) that helps identify which operations manual to use and its intended application.

Do you have the operations manual for your unit? If not you should be able to find it here,


RE: MTU 18V2000 troubleshooting

Thanks dear Mikel

the picture for the alarm on MDEC IS attached and starts appearing after installing new MDEC, it could be eliminated with old MDEC!!

Is this alarm preventing reaching nominal speed?

The problem this alarm as per manual caused by CAN1 BUS nodes are not connected. I checked wiring and found yes its not connected at all from day 1 with old MDEC , no alarms and engine was fine?

thanks again

RE: MTU 18V2000 troubleshooting

There are a number of means of providing a governor signal to an MDEC, including analogue signals (1-5V, 4-20mA), as well as via CAN. I suspect there's a setting on the new MDEC that expects a governor signal to be provided by CAN rather than an alternate means, thus it runs the engine up, and then falls over as it doesn't receive a signal.

It might be a discrete jumper setting somewhere, or it might have to be configured using MTU software. There have been a number of changes to the 2000 series over the years, the last replacement I was involved in included a number of ECU changes and additional hardware, even though the physical engine block being replaced was the same as the old one. MTU should be able to provide guidance.

RE: MTU 18V2000 troubleshooting

Do you think if I connected CAN1&CAN2 wires which are free now to the AGC ( DEIF type) to allow MDEC to receive feed back signal will clear the alarm?

best Regards

RE: MTU 18V2000 troubleshooting

That depends.
What provided the old governor signal?
How many sets are in use? Is this a single generator unit, or multiple parallel sets?

The Deif units can be configured with 2 CAN lines, but only one will provide any sort of governor signal, the other is normally used for load sharing. Connect the wrong one and its still not going to work.

Did you replace the AGC at the same time as the MDEC? Did the AGC provide some sort of governor signal previously, and if so, what was it?

RE: MTU 18V2000 troubleshooting

thanks again

AGC was not replaced.

this generator is emergency standby, SUPPLY POWER if main source of power CUTOFF, it can be shared as well.

I found no CAN in AGC connected , AS BOTH are isolated and FROM MDEC upto junction box.

in another way CAN1 nodes are EFG, CAN2 BCD nodes are ends at junction box , another nodes may used to do its job? not as per standard and alarms were cleared on old mdec.

thanks alot.

RE: MTU 18V2000 troubleshooting

To me, with the updates and descriptions, there are actually two separate issues, they may be related, they may not.
1. CAN Error
2. Engine won't reach rated speed.

Based on the piecemeal updates;
There is an AGC that is responsible for generator control, including engine governor (on the basis of 'it can be shared as well').
Previous MDEC used to work without a CAN interface. Reason for MDEC replacement unknown.
New MDEC flags CAN alarm.
Engine with new MDEC won't reach rated speed, sits at 1400RPM.

Governor signal control won't usually start until somewhere about 1400 RPM, below that the ECU handles startup, and then hands over to an external signal as needed, depending on the application.
The AGC should (providing that either load sharing or synchronisation is required, rather than pure standby) provide a governor signal.
I now expect that the governor signal is missing, this is causing the lack of running at rated speed.

The unit may well be able to operate without a CAN line in place, but it may either require other new components (e.g. a SAM unit rather than the PIM that may have been fitted previously, including CAN between the SAM and the MDEC) or it may need configuration to ignore the CAN line.

If the wiring for the AGC is unchanged then the signal for the governor should be able to be located, and confirmed to be connected. If this is ok then its still probably a configuration issue.

RE: MTU 18V2000 troubleshooting

thanks again

The mdec was damaged ,
the question is ? does the CAN1 alarm preventing the speed to raise or the governor to take the lead? synchronize will be if load sharing online in later stage.

do you thing its independent issue? I mean reach the speed of 1500 RPM and CAN1 alarm

RE: MTU 18V2000 troubleshooting

another , how to get mdec software to do congiration ?

RE: MTU 18V2000 troubleshooting

I think FreddyNerk gas you the best possible answers based on the information you have provided so far. Modern diesel engine electronic control modules has multiple ways of control engine speed and load. They also over time change defaults. While some ECM's come "bare" with no programming, most others have a "basic" program that will allow an engine to start and come to idle or minimum rated speed.

How was the new MDEC module "damaged"? Engine ECM's are usually pretty darn robust devices, they don't usually just fail, they get killed, mainly due to issue on the power supply and/or grounding. Early on many were damaged by improper welding procedures on the engine skids of the package/truck/machine they were installed in.

As you been told before,

Not coming up to rated speed is most likely a configuration issue if you are using the same device to provide the speed bias input signal. As I remember (and someone like Freddy or someone else with direct MTU experience may know better) is that the MDEC used a 0-5 VDC (actually .4-4.5VDC) default speed bias input, but newer ones I'm told can be configured to use many different analog speed bias input signals, such as 1-5VDC, +/- 3VDC, 500 Hz PWM or 4-20mA to name the most common I see. Speed control over CAN is also becoming more popular, but since you said the old CAN wires were not connected before, then speed bias over CAN was not likely how it worked before. What is the speed bias output signal out of your Deif AGC? I think this has already been explained to you above.

On the CAN error, again, likely a configuration issue or a change in the basic ECM programming looking for an active CAN signal. CAN errors of this type are either the CAN signal is out of range or the ECM is polling for a device on the CAN network and not getting a response. The troubleshooting guide for your specific engine and control should help you properly diagnosing the faults.

Engine service tool softwares are usually only provided to authorized service providers, since stricter emissions regulations this has gotten to be more the case. MTU may offer a customer version of the software, but you likely have to go thru an MTU dealer to get setup (typical of most all engine manufacturers). Most third party softwares I'm familiar with only allow reading codes, resetting certain alarms and changing a very limited number of parameters.

At this point I really think you need to contact your servicing dealer or ask the factory for help directly. Independent service providers may have technicians or field engineers how have the experience or technical expertise, but may not have access to the proper software or factory technical support.


RE: MTU 18V2000 troubleshooting

Engineer Mikel, many thanks for your comments, your description to condition is perfect, I am not sure if mtu cfigration for mdec memory will solve the problem by cancelling CAN alarm or not? I don know how to get help from FreddyNerk or contact him?

RE: MTU 18V2000 troubleshooting


There are two possibilities here as outlined previously, either the speed bias / governor signal is set to be read from CAN rather than where it should be for the Deif AGC interface, or there is a configuration issue with the MTU equipment.

Newer versions of the MTU MDEC (at least on the 1600 series from memory, likely on the 2000 series too) had an additional interface (I think it was called a SAM module) that the older versions didn't. That interface communicates through CAN, and if its absent, then its likely that the engine won't behave. If I recall correctly, the appropriate governor / speed bias signal was also connected to this box, but I can't be sure, and I can't check as I'm no longer with that employer.

Nevertheless, if you gained a new MDEC from MTU, then they should be able to advise whether or not a SAM unit or similar is needed, or other possible means of configuring the MDEC to accept whatever the speed bias signal is that is being provided from the AGC.

If you gained the replacement MDEC from an alternate source, then it may or may not be the correct unit for your application.
Since you haven't told us if the engine shuts down as soon as it reaches 1400rpm or whether it stops after a delay (perhaps the AGC flags an underspeed alarm), or even sits at 1400 until manually stopped, we can only guess as to how much of a problem the CAN alarm might be. What is certain, though, is that there is very little extra diagnosis that we can carry out over the internet with the information provided.

RE: MTU 18V2000 troubleshooting

yes, you are right .the AGC flags an underspeed alarm.you explination meets my conclusion , mtu provided new mdec without SAM, this will not all complete sequence of startup and operation. by this conclusion is It possible to mtu to cancel/override this from the memory if I send to them or we should i buy SAM?

RE: MTU 18V2000 troubleshooting

Ask MTU.

I can't guess at your configuration over the internet, MTU is the only one who can advise if your particular replacement MDEC needs a SAM to function properly or not.

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