Hi all, I have read some of the posts from years back that talk about the Grey Market MM30, MM40, and MM50. Hoping someone can help me. I am getting error code E-22 on the interference display. I have tried everything to make it go away, chased wires, removed sensors and put back on but still it stops the boom extension and retraction completely. Can still track and rotate, also can move bucket back and forth but can't use the boom. I do know that the red button under the seat temporarily disables the interference box, but that is only good for however long you want to listen to the beep and when you shut off and restart you have to press it again. I have tried disconnecting the sensors, but still doesn't work. So hoping someone might know of a way to just bypass the monitor permanently (I have never used it yet)? Cut a wire or two? Jump a wire or two? Any help would be greatly appreciated.
So, I did some measuring with a Multi-Meter today. And it looks like the position sensors on the boom have a dynamic resistance range around 1500-2000 ohms (and more depending on how far). Point is, I wonder if I was to install some resistors with say 2000ohms resistance at each of the sensors if it would satisfy the Logic to "Think" everything was good. Although the digital display wouldn't know how high the boom was, it would prevent it from erroring and disabling the boom? Thoughts anyone? (Although this is like a ghost town in here and it doesn't seem like anyone is actually listening).
Ok, as I talk to myself here in this thread, maybe it will help someone else down the road. Installed 2Kohm resistors into each of the 3 sensor wiring connectors and disconnected sensor. Unfortunately no progress as it just changed the error code from an E-22 to an E-21. I get E-22 with 1 or more sensors disconnected (without resistors), and then get E-22 with sensors connected. but only E-21 with resistors only. So, no progress, unless I am installing the wrong resistors.
I believe people are "listening" I think the problem is not many people have any helpful suggestions since it is a rare machine. As you must have searched around you've probably found that this is a common problem. At least it seems that way to me, almost any post I read about an MM something or other seems to never get a solution, or at least not one somebody wants to share....
Try checking this post out.... HeavyEquipmentForums
Oh I know, was just trying to be funny. There seemed to be a lot of discussion in a few other threads on this site a year or so ago. I was hoping to see if some of those knowledgeable people might chime in. I did post on those threads as well but nothing yet either. :-(
Yup, read everything I could find before I started my own. Even replied on two or three others on here
That's a bummer...hopefully someone chimes in. It would seem to me that someone with some kind of knowledge of the operating system would be able to bypass it…
Just wish I knew what e-22 was. I belive e-21 is supposed to be wring issue to potentiometers
Ok, here goes. I fixed it! (Or should I say over-road it) Step 1 (pictures 1 & 2) - Unscrew top of console, and you will find 2 screws that attach the monitor to the front of the console. Unscrew monitor controller so it is free. - Disconnect the two wire harness connectors from the monitor controller and feed out of the console so you have the monitor controller removed from the console completely Step 2 (Picture 3) - Unscrew the back of the monitor and find the two small red wires that lead around the circuit board to the front. This is the speaker for the horrible beeping noise, disconnect the connector and put the back back on the monitor controller.
Step 3 (Picture 4) - Open the panel under the seat and remove the 4 10mm bolts that hold the fuse panel and buttons on. On the back of the red button will be 2 wires that override the Monitor Controller. Be careful how you pull on the panel as it has bare 12V wires on the back and they can short out on anything metal while you are maneuvering it. Step 4 (Picture 5 & 6) - Cut the two wires between the connector and the button, Take the two wires that go to the wiring harness (not the stubs that are remaining on the back of the button) and strip and twist together. I recommend putting a wire clamp and/or electrical tape on this so that it doesn't short out sometime down the road. Put the panel back on with the 4 bolts.
Step 5 - Re-Connect the Monitor Controller to the wiring harness in the console. If you push the monitor controller to the forward most position inside the console, you can actually get the top back on properly. If you are unable to fit it in the right place then you will have to feed the wiring harnesses back through the front of the console, reconnect the connections, and attach it back on the front of the console with the original two screws. If you do this however you will have to stare at flashing 8888 every time you use your machine. I would probably suggest you put black tape or something over the display if this is the route you choose.
Here are some photos of my machine, it is a Mitsubishi MM40SR.
Glad to see you sorted it out! I'm sure someone down the line is going to really appreciate the steps you detailed on how to keep her going.
I was busy trying to figure out how to fix it and override the system when I realized that it already has an override, so why not just take advantage of it
Hi there, new guy here. I have a MM55SR that the CPU light comes on at console and when I try to move boom in or out. which means the boom does not move. Question is my console is a little different than the 40 could your fix work on my machine. Thanks
I don't know. I would suggest trying the button under the seat first? The reason I took the computer apart was because it was beeping from pushing the button. I also never used anything on it so figured it was best to just get it out of the way. Good luck and let us know how it works out!
I never had the beep after pushing button. everything works still except the in and out. I have a email out to the folks that have the retro setup. no answer yet to see how expensive that is.
please can you send me your email or mine is [email protected]
In dire need of schematic for Mitsubishi 55 SR. Any help will be appreciated !
This is everything I have... https://www.dropbox.com/sh/mzkhy958xi4isje/AAD-Zia6ZoL4VXffkdPXCeyXa?dl=0
Thanks Fordzilla for the information. I am tackling a unit that has been butchered, to put it mild. In the monitor, diodes CR18 and CR17 have been cutout. Looks as though the leads were soldered together. The buzzer was completely removed, window for led readout was painted over(black). Also a collection of moisture. I think the monitor was bypassed several owners back, so I am starting from scratch. Info on the monitor, Tokimec 45018347 mon-B, 45018366 Mon-A( the two cards making up the monitor). I opened the controller, no external identification. It seems to be running, displaying codes on two display segments. Does anyone know if these are the codes transmitted to the monitor? If anyone has changed/updated controls, I would be in the market for the monitor. Opinions and suggestions?
In the spirit of giving out information on these Mitsubishi MM series excavators (MM50SR, MM40SR, MM30SR) I’ve started to put all my information on my website www.woodandtrees.co.uk which you are welcome to access. It includes the MM50 electric diagrams, fault finding and error codes that “tool_king” and others have posted, Parts Manual and SL series engine operation, maintenance and service manuals. There is also some other stuff on my own machine MM30SR and information from “IronDino333” on ram seals. If anyone has more information (or write ups on what they have done on their MM machines) and are willing to share, just contact me via messages and I’ll add it to the site. Hopefully this is useful. Graham
I've recently acquired an MM40 in Australia with the same issues Fordzilla is talking about. The machine has been to heaps of mechanics with no good results. I'm anxious to try this out on mine. Keep the thread alive! Cheers!
Fordzilla, thank you so much. We just got a Cat 305.5 SR-2 and it was having all the issues you described. I followed you step by step and got it running again. This was after a local mechanic "fixed" the issue. It had stopped working 20 minutes after we got it back to our property so I decided to take a crack at it.
i have the same issue, after water came into the monitor panel, i change a capacitor burn, but i will try your methode to by pass this control panel, that i never use
an update I came to the conclusion my unit was no good as it was so I dug in. One thing learned, the control panel must have power/led/display on for the unit to have any function. On the schematic I have the bypass button has two wires one to the small remote unit and one to the main computer unit. While tracing out, found only one wire going to small remote. On separating the two boards. They were held together with a soldered in pin header. The first pin I cut with dikes pushed the printed circuit land from the board. This was no good. Found a fine tooth saw in a hobby kit and sawed the rest of the pins into with no issue. Moisture had gotten in the unit and the backs of the boards had a lot of crud on them. Cleaned this up. Had coil leads broken loose from board. re soldered. Went over the board with rtv anchoring capacitors and coils in place. Decided to power up and trouble shoot. Mounted boards on plastic where I could get to the back and front. Soldered leads in to take place of header. Powered up. Display and leds lit up. HEY THIS THING MIGHT WORK! It did. after abut two months Success. The folks from this forum sent prints and info to make this possible. Thanks
Great to hear you got this working. When water gets into these things they can become impossible to fix. So great job. If you have the time to write this up in more detail I'll post it on my website ( www.woodandtree.co.uk ) where I have a few articles about fixing problems with these machines.
Have you tried the "Fordzilla fix" yet? If so how about an update.
here you go
Can you send the manual for Mitsubishi mm40-55sr please. Here is my mail [email protected]
Can you send the manual for Mitsubishi mm40-55sr please. Here is my mail [email protected]
Hi! Is it possible that any of you know what CR17 and CR18 diodes are? I have TOKIMEC 45019347 and it's broken so much that I can't read anything.
To remove the the rotary position sensors from system you need to take 2 2K ohm resistors and make a voltage divider. The voltage value will be about 2.5 volts. Solder one end of one resistor to the 5 volt line, next connect both resistor to the signal line and last connect the other end of the second resistor to the ground line. I'm still looking for the schematics for the MM40SR myself. I hope this helps someone!
I got sick of trying to fix one after another problems with my 98 MM40SR computer positioning sensors and monitor I spent $375 to be told my monitor was fried and couldn’t be fixed and no replacement to be found by a high priced reputable repair company I got ahold of Tony-IMDynamics he fixed me up with a MM-R16–3 it bypasses all the original stuff all it uses is your original joysticks and the valve body I just put on in my machine today I am back in business no thanks to Caterpillar I live in the United States and they don’t recognize these machines
Great to hear you got your machine working again. It's good to know there are options to get the computer replaced, as I always wonder what to do if it breaks. Do you have any pictures of the new setup and advise about the installation?
It comes with all the information to install the unit you need to change the connectors on your spools no big deal it comes with all the hardware Tony is very knowledgeable I had to get the joystick voltage reducer because my joysticks were designed for 5 volts it’s not a cheap change over but when you think you’re going to have to scrap the machine it’s worth every penny these are a few photos that I took before I started the project I removed all the old computer hardware I could including wiring to the spools and joysticks and any wiring that went into the main wiring trunk I just unplugged them this makes the install much cleaner a that I have to do left is program the spool power witch is in the installation guide everything is working great on my machine now if you need any other questions answered let me know
Hello could you possibly provide this documentation again please? My dad's machine is experiencing the same problems. It's a mm55sr.. as well
Were you able to obtain any info or documentation on the mm55sr?? I have one as well. That needs this help. Thanks in advance.
Have at look at https://www.woodandtrees.co.uk/ This is where I've put all my information on these machines.
Thank you! Ive been searching information on these excavators mm55sr-2 and not much luck till I found this page and used this link to find a manual pdf and it didn't solve all of my questions but it did solve one mystery wire plug. Goes to the missing glow plug timer, part number found in pdf and there really commonly used and available. This machine was a big mess when I got to it but slowly it's coming together. I need to find someone else who has a similar machine that would be willing to help me by swapping pictures of how controls and wires go because I literally have some loose ends lol.
hey shadetree. im up here in clackamas county, or. maybe we can converse some time about our machines. i have an mm40.
Thank you! That would be pretty helpful. I have a couple modules that were sent out to be refurbished and have arrived back in now. I'll be putting them on in a couple days I hope and will report back.
⚠️ WARNING: Avoid IMD – $4000 Controller Failure, No Support, and Now I’m Building an Open-Source Replacement Hi all, I want to share my experience with IMD (IMDynamics) and why I strongly advise you do not buy their MM-R controller system , especially for excavator control retrofits like the Mitsubishi MM55SR. Why I Went with IMD I have a background in automation and system integration. When my excavator needed a modern proportional joystick controller, I thought: So I went ahead and ordered their MM-R system — a decision I now regret. ❌ What Happened After spending over $4000 NZD , I installed the system — and ran straight into major issues: Proportional joystick response is sluggish and non-linear Solenoids hammer and buzz violently — no matter the settings The system lacks the finesse and feel needed for accurate digging I followed every instruction and even ran their joystick calibration tool — no change. Trying to solve the issue, I went above and beyond: Sent them detailed voltage readings Shared joystick outputs in neutral and active states Provided photos of settings, wiring, and system behavior Tony from IMD even admitted that some customers had experienced the same issues — but since then, they’ve stopped replying. It’s been over two weeks with zero communication , even though they know I'm based overseas and likely can't do much about it. What I’m Doing Now Since I’m not getting any support, I’ve decided to build my own open-source replacement using modern, accessible components. I've already ordered the parts to build: A Teensy 4.1-based PWM controller Logic-level MOSFET drivers for the 12 V solenoids A touchscreen interface for settings and calibration Full safety and fine-tune logic: deadzones, curves, neutral switch, etc. The entire build will cost $400–$500 NZD total , and will be better-performing than IMD’s system with actual support. Bottom Line If you're considering buying from IMD — don’t . They may look like a professional outfit, but when things go wrong, you’re on your own — especially if you’re not local. I made the mistake of trusting them instead of building my own solution. Now I’m fixing that, and I’ll be sharing every step of the way to make sure no one else gets caught the same way.
Hello, did you ever complete yout system.