Bluetooth LE

Bluetooth Low Energy is the way a phone talks to WiCAN without any WiFi: Car Scanner or another ELM327 app, RealDash, or a CAN app of your own. It is off until you turn it on, and it has one rule to remember: while a phone is connected over Bluetooth, the WiFi access point is off.

Turning it on

Settings, BLE. Off on a new device.

1. Set Mode under AP Config to AP. Bluetooth is not available in AP+Station mode: the page greys the switch out.
2. Under BLE, set BLE Status to Enable and, if you like, change the Passkey: six digits, the first one not zero. The factory passkey is 123456.
3. Press Submit Changes. WiCAN restarts and advertises as WiC_<device id>, the same twelve characters as in the access point name.

Choosing Enable shows the warning: when a phone connects over Bluetooth, the WiFi access point is switched off.

Enabling Bluetooth switches MQTT and the battery alert off: the page hides their cards, and the firmware treats MQTT as disabled while Bluetooth is enabled.

Pairing a phone

• Pick WiC_<device id> in the app (Car Scanner, RealDash) as a Bluetooth LE adapter. The phone asks for the passkey the first time; type the six digits.
• The pairing is remembered (bonded): the phone reconnects without the passkey afterwards.
• One phone at a time.

The access point goes away while the phone is connected

As soon as a phone is connected over Bluetooth, WiCAN switches its WiFi off, access point included, so the web interface is out of reach. When the phone disconnects the access point does not come back by itself: disconnect the phone and power cycle WiCAN (unplug it) to get the web interface back. The other way round, a phone that joins the access point pauses Bluetooth until it leaves.

What an app can do over Bluetooth

The Protocol under Settings › CAN applies to Bluetooth as it does to WiFi:

Protocol	Over Bluetooth
elm327	Car Scanner, Torque and other ELM327 apps, and RealDash's OBD2 adapter mode. The ECU protocol must be picked by hand in the app, see Apps over WiFi and BLE.
realdash66	RealDash as a CAN device (Android and iOS; RealDash on Windows uses WiFi only).
slcan	slcan text frames, for an app of your own.
savvyCAN	GVRET frames, for an app of your own.
AutoPID	Not served over Bluetooth: AutoPID needs WiFi for Home Assistant and MQTT anyway.

For your own app: one service, FEE0, with a characteristic FEE1 that notifies the data WiCAN sends and a characteristic FEE3 to write to. Both require the encrypted, authenticated link the passkey sets up. Notifications carry up to 20 bytes unless the app negotiates a larger MTU, which Car Scanner on Android, for example, does not.

Troubleshooting

Symptom	Likely cause	What to do
The phone does not see WiC_...	Bluetooth is off, Mode is AP+Station, another phone is already connected, or a phone is on the WiCAN access point	check BLE Status and Mode; disconnect the other phone; leave the access point
Pairing fails	a wrong passkey, or the phone remembers an old pairing from before a firmware update or a reflash	type the passkey from the BLE card; remove WiCAN from the phone's Bluetooth list and pair again
The web interface is gone since the phone connected	expected: the access point is off while a phone is connected	disconnect the phone and power cycle WiCAN
The app connects but gets no data	the protocol does not match the app, or the ignition is off	elm327 for OBD apps, realdash66 for RealDash CAN; ignition on
Slow or stuttering data	Bluetooth LE carries less than WiFi, and the default 20-byte packets cost round trips	use WiFi for CAN traffic; keep Bluetooth for OBD apps