Unlocking Hidden Features on My BMW Z4 with the Carly App
Something exciting showed up in the mail today, and I couldn’t wait to try it out. I finally pulled the trigger on the Carly OBD scanner for BMW, something I’ve wanted for a long time but always felt was a bit too expensive. Thanks to a discount code, I decided it was time—and today, I tested it on my BMW Z4 (E89) to see exactly what hidden features I could unlock.
Unboxing and Setup
The unboxing experience is simple. Inside the small box, there’s just the Carly OBD device and a set of instructions. Setup is straightforward:
Download the Carly app
Plug the device into the OBD port
Open the app and connect via Bluetooth
That’s it. Once plugged in, the app quickly connected to the car and started generating vehicle insights.
Running Diagnostics (A Slight Heart Attack)
Before diving into coding, I ran a full diagnostic scan. At first, everything looked fine… until the issue count started climbing. By the time the scan finished, Carly reported 45 issues, including multiple ECU warnings. Not exactly what you want to see.
Thankfully, after digging deeper, it became clear that most of these were very old fault codes, some dating back 20,000–40,000 miles. The car currently has around 55,000 miles, so these weren’t active problems. Many of them appeared to be battery-related or long-resolved issues.
After clearing the codes and running the scan again, the result came back clean:
Zero issues. Huge relief.
Coding the Fun Stuff
With diagnostics out of the way, it was time for the real reason I bought Carly—coding hidden features.
Before making any changes, the app automatically created backups of each module, which is a nice safety feature. From there, I started exploring what could be customized.
Digital Speedometer (My Favorite Upgrade)
One feature I really wanted was a digital speed readout in the instrument cluster. BMW already uses that display area for cruise control, but Carly allows you to repurpose it.
I enabled the digital speedometer, coded it, and later tested it on the road. It shows your speed clearly in MPH right in the cluster, making it much easier to glance down without focusing on the analog gauge. Simple, but incredibly useful.
Comfort Access & Window Controls
Next, I moved into the comfort and convenience settings:
Comfort open/close with the remote
Power windows active after ignition off
Mirror folding via the key fob
That last one was especially satisfying. Previously, once the key was out, the windows were useless—which was incredibly annoying. Now, I can raise or lower the windows even after turning the car off.
Testing Everything in the Real World
I took the car to an empty parking lot to test everything properly.
Holding the lock button now folds the mirrors and raises the windows
Holding unlock drops the windows and unfolds the mirrors
Windows work even with the key removed
One thing I still couldn’t get working was closing the convertible roof via the remote. The windows and mirrors work perfectly now, but the roof doesn’t respond. It’s still an improvement over stock behavior, and there may be additional settings to explore later.
Final Thoughts
Overall, the Carly app delivered exactly what I was hoping for. It unlocked features that were already built into the car but hidden by default, and it gave me far more control over how my Z4 behaves day to day.
The biggest wins for me:
Digital speedometer
Window control after ignition off
Remote-based comfort functions
If you enjoy tweaking your car and unlocking factory-hidden features, Carly is absolutely worth checking out—especially if you can grab it with a discount.
