I'm trying to determine if is possible to control the stock cluster lights with an external device

From the wiring diagram on the ABS page

Both TC and ABS-
Instrument Cluster (Pink A13,c1) runs from hot on start mini fuse 19 (pink, b6, c2) 12v+ I'm assuming,

Then to a solid state device. I'm assuming this is using the signal wire voltage or other to determine which of the two lights is lit?

There is a connection from IC (gray a11) to star connector 1 (G) I'm assuming the signal wire.

The star connector looks like its the old gm version of canbus.

So without a truck ton of work, I'm probably SOL on controlling anything that hooks up to the star bus. Or does anyone have any smart ideas?

My stock ABS is dead. I'd rather not stare at the warning light all the time. Pulling mini fuse 19 looks like the easiest way to turn it off. I was hoping to hook up my new mk60 system through the existing warning bulb. I suppose I could highjack the hot wire with a relay and get the ABS to only come on when the mk60 provides it with 12v. Or maybe just hook up the 12v wire from the mk60 to the pink wire instead. If its just powering the light instead of the IC it might work.

 

Should we know what an MK60 system is?
The easiest path would be to just remove the bulbs.......

 

It's the Griffin Missile System. My car doesn't have that RPO but it sure would come in handy for some of the traffic around here.

 

Its a stand alone abs system I'm using to replace my failed 99 oem system. But fwiw it could apply to anyone who is replacing factory modules with something like a haltech, etc.

 

Stumbled upon this thread because I will soon be in the same boat and do not wish to stare at the warning lights or deal with cluster warnings at every startup. Did some testing last night with a Bluetooth OBD dongle and terminal app on my phone. It looks like the only way to go about fixing this is to transmit a heartbeat message on the J1850 bus. With my car off and ignition on, I saw what appeared to be heartbeat messages from the EBCM blasting out every 100-200ms. These are the recurring hex messages that I saw:

My my research, the first message (88 25 28) is a message directed at the EBCM (0x28). The second message (E8 FF 28) is a broadcast FROM the EBCM (0x28) indicating that it's alive.

These messages stopped after unplugging the EBCM. I did some further testing and was able to isolate the messages for toggling the TC off and on as well as when turning the steering wheel (SWPS signal). Given this, it seems like the only course of action is to inject the heartbeat message into the J1850 bus via a microcontroller and appropriate transceiver. There's really only 1 transceiver on the market that can do this and it's pretty cheap (~$45) plus the cost of an Arduino, ESP32, or any other microcontroller. I'll be ordering the hardware soon and will give it a try.

EDIT: Here's the module that I ordered - https://www.ebay.com/itm/267628098504. Already have a preliminary Arduino sketch written up (thanks Cursor!) based on the available code from the vendor.

 

Just FYI, Pete from OBDX Pro also makes a J1850 transceiver. It's not listed on the website but I'm pretty sure he'd still be happy to sell them.

Good job figuring out the ABS heartbeat, BTW.

 

Oh that's good to know. I'll send him an email later to inquire about it, appreciate the tip!

With the help of Codex, I crafted a super simple Android app to monitor bus messages and save it to a log. Looks like the heartbeat goes out every 500ms or so. Need to go for a drive to see what other EBCM related traffic (besides SWPS and TC status) this can sniff out. Would be cool if I found a way to trigger the ABS fault light using the MK60 LED output.

 

Which MK60 are you installing?
One from the E46M3, or one of the later E1/E5 units?
Lots of info online, and a Facebook group dedicated to it.
Just installed the MK60 E5 (BMW E90 series) on my 944. Tested it briefly last Friday at an autocross practice, real test will be this weekend with NASA.

 

MK60 is the ****!

and this thread delivers. I love that we are reverse engineering solutions to keep our nearly 30yr old cars on the road!

also in to hear which MK60 you're running and if you used the late C6 or C5 unit bearings

 

Does the MK60 have the ability to do Active Handling sorts of corrections, by braking individual wheels?
If so it could be fun to try to get an Arduino with an IMU and SWPS input to send canbus messages to trigger that.

 

the commonly retrofitted systems have a yaw sensor, but as of currently- I don't think anyone is making hardware or software to control individual wheels like the AH does

BMW's do have Dynamic Skid Control, so in the OE application there is individual brake control available

 

Theoretically, if you transplanted the entire system, and you could make it talk to the ECU, it would all function.
Need to include the precharge pump for 'brake-pedal-off' stability control brake applications.
Other than straight up traction control, not sure how important the ECU com is...
Just happy to have ABS finally!

 

Yeah, it would take some work, but it sounds like fun work. There's another thread here about interpreting the steering wheel position sensor signal with an Arduino, and that plus yaw and speed seems like enough to get some basic functionality.

Some sort of ABS swap is definitely in my future, and if there's potential to do this kind of thing with MK60 that would be point in its favor vs the Delta ABS system. Partly because AH spared me a bit of embarrassment the last time I did a track day in the rain, partly because it just sounds like a fun thing to design and implement.

 

Here's the GitHub repo that has some more info about this protocol and how GM uses it: https://github.com/garnerm91/J1850/b...ames/known.txt

This is pretty promising, particularly the "Lights/DIC message" section since the message structure matches what I saw when I toggled TC off/on. With a microcontroller it should be pretty simple to have that +12v from the MK60 LED output trigger the appropriate "ABS light on" message.

 

Update! I got it to work. Received the transceiver yesterday. Today plugged in all of the boot sequence and heartbeat messages into an Arduino sketch and wired it up. No more errors if the ABS is unplugged!

 

Hell yeah!! Good work man!!

Your project will undoubtedly be invaluable to keeping these cars on the road for many more years

 

So here's the GitHub repo with wiring instructions and the Arduino sketch: https://github.com/eperez84/C5-J1850VPW-comms

I have yet to test drive the car with this wired up. I don't know if the PCM or any other modules expect additional communications from the EBCM while the car is in motion, so it's possible that additional bus traffic might have to be simulated. I'm hoping to go for a test drive either tonight or tomorrow.

 

I think it varies a bit depending on which car the mk60 was sourced from. The m3 ones will let you trail brake a bit more and take a motorsport flash. The NPC modules aren't especially active. I have a normal mk60 e1 unit. When you're in the BMW ABS software I know there are some settings for that sort of stuff, but I wouldn't want to enable it without a way to control it from the cockpit. There is a wire for DSC in the pinout that might be able to control it, but its a canbus unit, so I wouldn't be surprised if you'd need to figure out a way to talk canbus to it.

 

Very cool engineering. I'll have to build one soon. TBH the light doesn't bug me too much as a track car, but it'd be nice to turn them off if I have to sell.