Both say be very careful in selecting the battery -- must be a real Panasonic VL2020, and not the CR2025, ML2020, etc. The "pro" said go with the 180 degree leads, modify both leads, and solder on a short piece of wire to one lead not the battery itself to prevent heat damage (see his pics). That way I can use the key built into the fob to open the car, then change batteries before starting it. The standard key fob has a rechargeable battery. The key fob for Comfort Access uses a CR2032 battery. This summer, I bought a 2011 BMW Z4 3.0i—just like yours. How to change key battery keyless remote.. This video is for educational purposes only. Use this video at your own risk. For more information please refer to How to Replace BMW Wireless Key fob in less than a minute. BMW 5 Series 2010-2015 . This one is for the 2015 BMW 535i - DIY The battery must be replaced by qualify auto locksmith if there is no longer any voltage supply for the remote key. The rechargeable battery cannot be replaced individually and is charged when the remote key is locked into position in the ignition lock. A 125 kHz interface within the ignition lock executes the recharging. - Diamond key functions & the truth about the BMW diamond key transponder and proper initializing and the truth about the 10-key limit to programming your own keys at home & opening, charging, recoding, & battery replacement of the new-style diamond key & converting the old-style 1996-2000 "square" key to a diamond key & how to replace the When the chain snapped I tried starting the cars several times which drained the battery of the car completely. Car was coming up with the message that the remote control wasn't in the car. The car is fixed now and battery is full. The strange thing is that one of the keys isn't working anymore. For instance, in the 2019 BMW X5 you’d have to quickly press the key fob’s lock button three times, then hold it for your engine to launch. Beforehand, you’d also have to make sure you have the ‘remote engine start’ function enabled in your iDrive settings. To do that you have to: 1) Go to your iDrive menu. 2) Choose ‘Car’. Press the BMW logo on your BMW key fob 3 times while holding down the unlock button. Let go of the unlock button after the third time you’ve pressed the BMW logo. Then, turn on the ignition, and your new key should be paired with your BMW! It is possible that the Energizer batteries can't supply enough current for the key and the voltage drops too low. I looked at the battery datasheets, but the load current has not been specified by either manufacturer. These batteries were designed for a very small load. My F11 keyfob has a much larger CR2450 battery.. bk4zGz.