E46 Wheel Speed in Latest Firmware

eacmen · Post by **eacmen** » Thu Oct 05, 2017 1:40 am

So I am trying to get wheel speed working with the latest CAN Mapping support. The E46 Wiki still has the LUA script and the link to the "database" only has like 4 CAN PIDs that are listed for E46.

When I log pid 496 in the garage (ECU on but car not in motion) I get the following output:

Code: Select all

&#91;496.0&#93;&#58; 10, 0, 10, 0, 10, 0, 10, 0, 
&#91;496.0&#93;&#58; 10, 32, 10, 0, 10, 0, 10, 0, 
&#91;496.0&#93;&#58; 10, 64, 10, 0, 10, 0, 10, 0, 
&#91;496.0&#93;&#58; 10, 96, 10, 0, 10, 0, 10, 0, 
&#91;496.0&#93;&#58; 10, 0, 10, 0, 10, 0, 10, 0, 
&#91;496.0&#93;&#58; 10, 32, 10, 0, 10, 0, 10, 0, 
&#91;496.0&#93;&#58; 10, 64, 10, 0, 10, 0, 10, 0, 
&#91;496.0&#93;&#58; 10, 96, 10, 0, 10, 0, 10, 0,

Is my LF wheel speed sensor broke or is that the intended output when not moving?

Based on all the research I have seen each wheel speed is 12 bits of each 2 byte chunks of that PID. However given that logic when I am at rest in the garage I have a speed of 2560kmph.

I saw this post from Mustangkev:
viewtopic.php?p=26835#26835

I used his offsets and I get the same results. This is an E46 M3, are there any differences between the M3 PIDs an others?

Post by **brentp** » Wed Oct 11, 2017 4:25 pm

Not familiar with the E46 wheel speed sensors.

If that's the raw data coming from ID 496, and it doesn't match what the script or mapping expects, then perhaps there's something weird with the sensor.

How does the original Lua script work with the wheel speeds? That would be the biggest tell.

Mustangkev · Post by **Mustangkev** » Fri Oct 27, 2017 6:20 pm

Not sure if you solved this by now but the bits that are at the end of the wheel speed sensors can cause erroneous readings. It’s possible that your reading them by mistake. When I first got the wheel speeds working I used a small script to remove these readings which is here:

viewtopic.php?t=4488&highlight=

Try this and see if it solves your problem. If so, then It should indicate where the issue is.

kijones · Post by **kijones** » Tue Feb 20, 2018 5:09 am

I hve noticed that my wheel speed sensors are all reading erratic after the update also

Post by **brentp** » Tue Feb 20, 2018 5:14 am

Hi, There were fixes made in the 2.13.0 firmware around little-endian bit mode encoding that coincidentally broke the E46 little-endian mapping. We're investigating why this is happening, and what to do to account for both. We won't release 2.13.x firmware out of beta until resolved.

You can use 2.13.0 if you want to remove wheel speed sensors for now, or, just fall back to 2.12.0.

Thanks,