When your 2020 Acura TLX won't start because the key fob battery has died, Acura's keyless access system can't detect your fob. However, backup methods allow starting even with a completely dead fob battery.
Why Dead Key Fob Prevents Starting
The TLX's Keyless Access System uses wireless communication between your fob and sensors in the vehicle. When the fob battery dies, it can no longer transmit the signal that authorizes engine starting. The system sees no key present and refuses to start.
Backup Starting Method
Acura provides a backup for dead fob batteries: hold the fob directly against the start button. A low-power reader embedded in the button can detect the fob's passive transponder chip that doesn't require battery power. With the fob touching the button, press and hold the button while pressing the brake pedal.
Door Unlocking with Dead Fob
If you can't unlock the doors, the fob contains a hidden physical key blade. Press the release button on the fob and extract the key blade. The TLX's driver door handle has a keyhole that may be hidden behind a cover - use the blade to unlock the door manually.
Key Fob Battery Replacement
The 2020 TLX key fob uses a CR2032 battery. To replace: release and remove the key blade, use a small flat tool in the notch to separate the fob halves, carefully remove the old battery noting orientation, and insert the new battery with the positive (+) side visible. Snap the fob back together.
Driving for Battery Replacement
The backup starting method works but is inconvenient for regular use. Once you've started the car using the backup method, drive to purchase a replacement CR2032 battery. Most pharmacies, electronics stores, and grocery stores carry this common battery type.
Low Battery Warning
The TLX displays a low key fob battery warning well before complete failure. When this warning appears, replace the battery promptly to avoid being stranded. The warning typically provides several weeks of notice.