I have a Toyota instrument cluster. My original instrument cluster has a MPX + and MPX - communication line. The new cluster has a CAN-H and CAN-L communication line. Are these completely different systems? I'm just wondering if I'll be able to get the new cluster to read information on the can h and can l lines via the MPX+ and -

 

I have a Toyota instrument cluster. My original instrument cluster has a MPX + and MPX - communication line. The new cluster has a CAN-H and CAN-L communication line. Are these completely different systems? I'm just wondering if I'll be able to get the new cluster to read information on the can h and can l lines via the MPX+ and -

If you have no evidence to support the proposition that they are compatible you should assume that they are not. I am quite familiar with all things CAN, but I don't know anything about MPX. Provide me a link and I can try to answer your question.

 

Here's a service document describing the MPX system. MPX is the umbrella term for a 3 bus system consisting of CAN, BEAN (Body Electronics Area Network) and AVC-LAN (Audio-Visual Communication Local Area Network). Each has it's own purpose and protocol - the two latter ones being Toyota proprietary. I think this document is for a Prius. Other models may vary in their uses of the various busses. On the Prius at least, the combination meter uses BEAN. see pp4.

Good luck!

 

Here's a service document describing the MPX system. MPX is the umbrella term for a 3 bus system consisting of CAN, BEAN (Body Electronics Area Network) and AVC-LAN (Audio-Visual Communication Local Area Network). Each has it's own purpose and protocol - the two latter ones being Toyota proprietary. I think this document is for a Prius. Other models may vary in their uses of the various busses. On the Prius at least, the combination meter uses BEAN. see pp4.

Good luck!

I think I found that service document as well, but there were no details on on physical layer signaling protocol.

 

Thank you for the replies and apologies for late reply, was a busy weekend. I've got the following two attached schematics for the two instrument clusters. The colour version is my instrument cluster currently in the car and the black & white document is the new cluster from the next generation of the same car. I've managed to get the new cluster powered up on the bench and got things like the steering switch pads, fuel level and turn signal's working. However, most of the other things seem to come from the CAN-H and CAN-L on the new cluster. As you can see on the older cluster it comes from MPX- and MPX+. Any suggestions of what I can try?

 

MPX is a communication network consisting of 3 different types of communication with CAN being one of them. I think in order for communication to happen for your cluster, you need to use a gateway in your setup. I am assuming that you are doing this on a bench as you have not provided much in the way of details so I can only speculate. Can you provide more information on the donor cars? The gateway is like a subway station. People go in and out at different speeds with different destinations. The gateway routes the signals and allows them to carry on to another destination regardless of speed. It may be difficult to get a CAN only cluster to communicate on MPX because of communication speeds. You may only get partial information.

 

Thank you @bwilliams60 The current cluster is from a Lexus IS250 2nd Generation and the new cluster is from the 3rd generation. I am currently testing the new cluster on the bench, but the idea is to try and retrofit the new cluster and replace my old cluster with it. As a lot of the information come from the CAN i'm thinking to try and somehow hook it up to the car and see what kind of readings I can get. From looking at that diagram one of the MPX connections seem to come from the CAN-BUS and another from the gateway. Would I need to get a CAN-H and CAN-L directly from the gateway?

Is there a way I can connect the new cluster's CANL and CANH to some sort of device and listen for what kind of data the cluster is looking for an then somehow simulate this on the bench?

 

There are all kinds of CAN sniffers that you buy to monitor CAN data in your car. Whether you can decipher it all is another story. The problem is you are now entering a zone that we consider hacking and although it can be done, it is not done easily and without a lot of research. As for putting the new cluster into the older car, we have been down this road before and it didn't go well for the last guy that tried. You can tie the new cluster into the CAN bus on the old car but I think you ate going to be missing a lot of data. Hard to say until you try. If you have time, go for it and see what happens. Remember too that everything CAN has to have an address online in order to communicate. I am not sure how you are going to pull that off. Good luck.

 

I have plenty of time to experiment and try this out. One option i'm thinking is if I tap into the CAN wires from the gateway and then attach it to the new cluster and see if i get any responses. Or could I plug in some sort of can analyser at the gateway CANH and CANL and then read the output and then use the same can tool to send that data on the bench to the new cluster. This will mimick exactly what the new cluster will get if it was tapped in to those wires would it not? I've come across this ebay item: https://www.ebay.co.uk/itm/173943295023 Seems like a USB to CAN and allows connecting wires using screw terminals which can be handy. But I don't know much about this, what software would I use to read data and if I wanted to send data to the new cluster what software would i use?

I've attached the CAN wiring diagram from the car I want to put the new cluster in. Looking at it, the Network Gateway ECU (J76) seems like it has CA1H and CA1L which then goes to a junction box providing CANH and CANL to many things. Is the CA1H and CA1L the same as CANH and CANL? can I tap into this to read can data? The technical docs for the car says if disconnecting the network gateway ecu that the negative of the battery should be disconnected and left for 90 seconds and to discharge any static by touching the car to prevent airbag deployment. Does this mean even to tap into the CAN wires I will need to do this?

 

Just wondering, what about pins 6 and 14 on the ODB2 port? they seem to be CANH and CANL. I cut a old ODB2 extension cable I had and exposed the wires going to pin 6 and 14 and tried connecting the two CAN cables going to the new cluster but didn't get any change on the cluster. I'm sure some of the data is compatible, so i'm thinking maybe you cant retrieve anything from the ODB port pins 6 and 14 or that extension cable connector isn't helping?

Looking at the CAN schematics of the car i uploaded above, it seems like from the gateway, there is a CAN going to the ODB port which is referred to as J21 (DLC3). So I'm wodering should there be some sort of data coming out of those two pins? I have a diagram from the manufacturers tech doc of the ODB port below, can someone advise please? Thanks

 

Do you have power and ground and switched power going to cluster?

 

Do you have power and ground and switched power going to cluster?

Yes, I've wired:

pin 21 to switched +12v
pin 22 to always +12v
pin 31 & 40 to ground

I've put a rocker switch between the always +12v and the switched +12v to mimic ignition by turning the switch on and off I am able to get the cluster to boot-up and shutdown. I came across the following piece of kit https://www.ebay.co.uk/itm/233401043974

I've liased with the seller and it's supposed to be a all-in-one standalone solution. I'm told that it can be plugged in to the CAN and records the CAN messages and then I can plug it into the new cluster and playback the messages to see which responds etc. Or I can load the messages on the laptop and edit and try playing back etc. It's a little expensive but if it does all that seems like a good piece of kit. Will this be a good start?

 

If you are going to work on a test bench, this will work fine to mimick the care it came out of but I understood you want it to replace an older cluster in your car. As I mentioned earlier, there are several CAN recorders out there and you can record and watch the messages all day long. You can even narrow them down to an event like turning on the turn signals, but you cant write that information into your old setup to make the new cluster work, unless you can hack the OEM software and introduce it into their language. I shouldn't say can't, but you would have to be pretty brilliant to pull that off. I am surprised however that you get absolutely no functions out of the new cluster on the CAN bus. That kind of tells me that even a company that builds the same vehicle, has changed the language even between the years. CAN bus security is a big business in the OEM world. People that can hack it, have a job for life with an OEM for sure.

 

Thanks. I purchased that kit just to see and experiment and I have a few other CAN related projects lined up so the same kit hopefully will come in handy. I came across a post of a guy who has done this exact swap but doesnt want to share any information other than the fact that he made a inline can-bus translator to translate messages received on the car to what the new cluster likes for the same equivlant message. Have you heard of inline translators? I'm assuming lets say for example my car currently sends a certain format of CAN message to say gear position is 1 2 or 3 etc and the new cluster the message format is different, so if I can figure out the message by reading the messages from the new car and comparing and then translating that in theory should work right?

 

Below I have a diagram of the CAN BUS system wiring from the manufacturers documentation. DCL3 is the ODB2 port. Does It looks like it should contain some data?

 

The Data Link Connector (DLC) is a direct link to the CAN bus on this system. You can get all the information travelling over the CAN bus at this point.
Can you share more information about the guy you were referring to? If you don't feel comfortable putting it on here, please PM me on this. to my knowledge, there are no inline translators but maybe I am going to get educated real quick. There are sniffers that you can manipulate data with but I have never seen where you can take raw data and change it mid-stream to go to another format. I would be very interested in this.

 

I just realised the reason I probably got no signal when i hooked up the CAN from DLC3 is because silly me I read the pins wrong way round on the extension that I cut to expose some wire. The pinout refers to the OBD port and I was going based on that but looking at my extension socket so hence the pins are flipped. Silly me. I will try again on the weekend, this time maybe I can just push-in some male terminal pins attached to some wire going straight to the DLC3 pins.

In regards to the person who did it, i read this some time back over a few years ago on a forum so would need to try and find it again. There wasn't much info at all just pictures and the mention of a inline translator.

But logically lets say for exampe my current car sends a CAN message about tyre pressure and I am able to find the message and the values for that message. Then lets say the new cluster has a different message format for the tyre pressure and lets say I figure that out. The device I ordered can playback CAN messages. So technically, isn't it possible with something like a arduino if a certain can message is deteted then it sends a signal to another arduino to send the correct message on to the CAN ?

 

That is more for a programmer. I will bow out at this point as it is over my head. Next step on my learning curve but you may be right. I still think you would have to be able to write to the EEPROM or flash memory to do this. I may be wrong. Any programmers reading this thread?

 

Again I tried using a cut-out OBD2 extender this time with the correct mapped pins 6 and 14 wires. But because the wire was short for testing, i extended it with a length of electric cable by about 80cm. But I still wasn't getting any reading and i'm told that certain ODB data is exactly the same on both models. So the fact that the cluster isn't reading anything means it's not reading from pins 6 and 14 via the extender. Either it doesnt like the extension wire or I still am not getting the pins right I'll wait for the CANBUS recorder to arrive and see if I can manipulate anything using that.

 

If you connect just the newer cluster to a scan tool via CAN bus, can you talk to it? If you do the same with the old cluster, can you talk to it? If you can talk to each ot them separately, you should be able to talk to them together.. dont forget the CAN bus lines need 120 ohm resistors on there as well.