[Joe240]

Yes, I know this has been beated with a stick throughout these forums on the 2 series. But I'm hoping someone can provide some insight and allow me to get a good dyno run for once.

Car: 2020 Z4 M40i (rwd with mLSD and ZF8)

Issue: Car throws errors on RWD dyno such as chassis stability, parking brake malfunction, and some others. Scanner reads these codes: P152B, P152A, U0418, C0501, and C0507. P152A is showing as a permanent code, but scanner clears everything and turns off the CEL. P152A reads "Vehicle speed, plausibility: Minimum speed under load not reached." To me, this sounds like the speed sensor is in the front wheels and tripping all stability control, causing loss of power and automatic up-shifts at 3k rpm.

Resolutions attempted: Turn car on (not in chassis dyno mode), sport+, manual shift, DSC off (held traction button). Throws all of these errors and has the same outcome. Manual mode auto upshifts at 3k rpm with loss of power.

Also tried to put in chassis dyno mode. Since this is a digital cluster and no button in the bottom left like the older analog clusters, had to use new method to get into chassis dyno mode. Car in Accessory mode (one press of IGN), then pressed 3 times quickly to put in diagnostic mode (otherwise the care doesn't allow changing of functions on the cluster). Hold "BC" button on left stock for 15 seconds. Menu pops up in the cluster. Press BC button to select Chassis Dyno (no numbers next to it, but it is the 3rd option). Hold BC button on Chassis Dyno. Screen changes to say "Chassis Dyno/DSC off?" Hold traction button to disable DSC. Press BC button to confirm Chassis Dyno/DSC off. Cluster menu closes and cluster says "Test Mode! Turn off ignition to exit." Try doing the pulls and same issue arises.

Once the errors come up on the dash, the vehicle appears to not be allowed into Chassis Dyno mode anymore. It does not provide the "Test Mode!" confirmation shown above. Scanner has to be connected and codes all cleared to get the display to show Chassis Dyno mode confirmation again.



Really hoping someone else on the forums has ran into this same/similar issue and is able to provide some assistance. I've had the car on 2 different dynos from different businesses, both having the same issues. One was a dynamometer and the other was a mustang dyno. The mustang dyno allowed us to do the run in, but stopped the run in at 125mph and told to coast down. Might have been due to the 2020 z4 models wasn't an option so we had to select a 2019 z4 sdrive30i (same gearing and tire options so theoretically should have worked).