{
  "$comment": "Single source for signal identity. Topic name and envelope unit are both derived from these entries and are never authored separately. source=obd2 is standardised; source=z27ag is reverse-engineered and lives in the DBC.",
  "signals": {
    "engine_rpm": {
      "unit": "rpm",
      "type": "number",
      "source": "obd2",
      "description": "Engine speed",
      "range": [
        0,
        8000
      ]
    },
    "vehicle_speed_kph": {
      "unit": "kph",
      "type": "number",
      "source": "obd2",
      "description": "Road speed",
      "range": [
        0,
        255
      ]
    },
    "coolant_temp_c": {
      "unit": "celsius",
      "type": "number",
      "source": "obd2",
      "description": "Engine coolant temperature",
      "range": [
        -40,
        215
      ]
    },
    "intake_air_temp_c": {
      "unit": "celsius",
      "type": "number",
      "source": "obd2",
      "description": "Intake air temperature",
      "range": [
        -40,
        215
      ]
    },
    "throttle_pct": {
      "unit": "percent",
      "type": "number",
      "source": "obd2",
      "description": "Throttle position",
      "range": [
        0,
        100
      ]
    },
    "engine_load_pct": {
      "unit": "percent",
      "type": "number",
      "source": "obd2",
      "description": "Calculated engine load",
      "range": [
        0,
        100
      ]
    },
    "fuel_level_pct": {
      "unit": "percent",
      "type": "number",
      "source": "obd2",
      "description": "Fuel tank level",
      "range": [
        0,
        100
      ]
    },
    "intake_pressure_kpa": {
      "unit": "kpa",
      "type": "number",
      "source": "obd2",
      "description": "Intake manifold absolute pressure",
      "range": [
        0,
        255
      ]
    },
    "maf_gps": {
      "unit": "g/s",
      "type": "number",
      "source": "obd2",
      "description": "Mass air flow rate",
      "range": [
        0,
        656
      ]
    }
  }
}