AutoPID

AutoPID is the mode in which WiCAN reads the vehicle by itself: it asks the car for values on a schedule, decodes the answers into named parameters such as engine speed or battery state of charge, and hands them to Home Assistant, to MQTT and to anyone who asks over HTTP. The web interface calls the whole area Automate.

Switching it on

1. Under Settings › CAN, set Protocol to AutoPID and press Submit Changes. In this mode WiCAN talks to the car through its built-in ELM327 interpreter, so no app can use the bus at the same time.
2. Open Automate and choose what to read: the standard OBD-II values, a vehicle profile for the make and model, or requests of your own. Press Store.
3. Restart WiCAN (System › Reboot, or Submit Changes on the Settings tab). The tables take effect at the next start.

AutoPID needs the ignition on, or the engine running, to get answers. Polling, Home Assistant and MQTT need WiCAN on your network (AP+Station), the HTTP endpoint works on the access point as well.

The Automate tab on a device set up for a car: standard PIDs, a vehicle profile and a custom PID.

The three tables

Section	Rows	Where they come from
Standard PIDs	the OBD-II values every car must answer, as far as yours supports them: engine speed, vehicle speed, coolant temperature, fuel level, intake temperature and some 180 more	Scan PIDs asks the car which ones it supports; you add the ones you want
Vehicle Specific	the values only your make and model carry, such as battery state of charge, cell voltages or tyre pressures on an EV	a vehicle profile from the published list, see Vehicle profiles
Custom PIDs	requests you write yourself, with your own decoding	you, see Custom PIDs and expressions

Every row has a period in milliseconds: how often that value is asked for. WiCAN works through the rows one after the other, so many rows with short periods slow each other down; a second per value is comfortable, five seconds is plenty for a home dashboard.

Standard PIDs

Three standard PIDs chosen after a scan.

1. Set Standard PIDs to Enable.
2. Pick the ECU Protocol of your car: 6 (CAN 11-bit ids, 500 kbit/s) fits almost every car; 7 is the 29-bit variant, 8 and 9 the 250 kbit/s variants. There is no automatic detection: if a scan finds nothing, try the next one.
3. With the ignition on, press Scan PIDs. WiCAN asks the car which values it supports and fills Available PIDs with them (the scan takes some seconds; on a car that answers everything, the list is long).
4. Pick a value from the list and press Add PID. Each row opens on a click: Receive Header (leave empty unless the answer comes from a module other than the engine), Period(ms) (1000 or more), Destination Type and Destination, explained under Where the values go.
5. Store, then restart.

A standard PID row. The name is fixed; the period and the destination are yours.

The names are the PID number and a short description, 0C-EngineRPM or 05-EngineCoolantTemp, and that is how the values are called everywhere else: in Home Assistant, on MQTT and in the HTTP answer.

The settings at the top

User Destinations: the grouped snapshot goes to one MQTT topic every 5 seconds.

Setting	What it does
WebHook and the Home Assistant card	The push to Home Assistant, set up from the Home Assistant side, see Home Assistant.
Grouping	Enable publishes all values together as one JSON object, every Cycle Time(ms). Disable leaves only the per-row destinations and the HTTP endpoint.
Destination Type	With grouping: MQTT Topic publishes the snapshot to the Destination topic; Default publishes nothing on a cycle, the snapshot is only served over HTTP and to Home Assistant.
Destination	The MQTT topic for the grouped snapshot. Empty means the MQTT RX topic of the device.
Cycle Time(ms)	How often the snapshot is published, 1000 or more.
Polling	Enable reads the car continuously. Disable reads it only when someone asks: an HTTP request to /autopid_data, or the MQTT command get_autopid_data, triggers one round of requests.

Where the values go

Destination	What arrives	When
http://<wican>/autopid_data	all values as one flat JSON object: {"0C-EngineRPM":716,"0D-VehicleSpeed":173,"05-EngineCoolantTemp":21}	whenever asked; with Polling disabled the request itself triggers a round
The MQTT Destination topic	the same object, with Grouping enabled and Destination Type MQTT Topic	every Cycle Time
A row's own topic	a row with Destination Type MQTT_Topic publishes {"name": value} to its Destination every time it is read; MQTT_WallBox publishes the bare number with two decimals, the format wallbox chargers expect; Default publishes nothing by itself	every period of that row
Home Assistant	the values, their units and classes, and the device status	every webhook interval
http://<wican>/load_car_config	the names with their class and unit, for a program that wants to label the values	whenever asked

The values are rounded to two decimals. A value outside the row's Min Value and Max Value is dropped.

Good to know

• The ECU status. WiCAN counts the car as online while at least one row gets answers, and as offline once every row fails; the status is published to Home Assistant and shown in the ecu_status field of the status endpoint.
• Ignition off. Rows time out and the values stop changing. WiCAN keeps asking; on some cars, polling a parked car can keep a module awake or set off the alarm. Sleep mode stops polling with everything else, see Sleep and battery alert.
• One protocol at a time. With AutoPID chosen, port 3333 is not served: Car Scanner and the other apps need the protocol switched back.
• Where it is stored. The Automate tab is kept in its own file on the device and is part of the configuration download, see Backup and restore.

Troubleshooting

Symptom	Likely cause	What to do
Set protocol to AutoPid and reboot to be able to scan	the protocol is not AutoPID yet	Settings › CAN › Protocol AutoPID, Submit Changes
The scan finds nothing	ignition off, or the wrong ECU protocol	ignition on; try protocol 7, then 8 and 9
/autopid_data says No data available	no rows yet, or no answers yet	add rows, Store, restart; ignition on
Values never change	the car stopped answering (ignition off), or the period is long	check the ignition; the period of the row
Nothing on MQTT	MQTT is not enabled or not connected, or grouping is off and the rows have the Default type	MQTT; enable Grouping with MQTT Topic, or set a row's type
Nothing in Home Assistant	the webhook is off, WiCAN is not on the network, or the protocol is not AutoPID	Home Assistant