Are you curious about the various diagnostic data you’re seeing reported from your vehicle? This article is meant to help give more insight and understanding regarding the multiple diagnostic values your device may be reporting.
Device Diagnostics
Please see the below table for the diagnostic type and a corresponding description. This data doesn’t necessarily relate to your vehicle’s engine diagnostics, but rather to the device’s interpreted/accumulated data that can be influenced by reading the diagnostic port.
| Type | Description |
|---|---|
| Max Speed | The maximum GPS speed reported from the device within its predefined update interval |
| Instantaneous Speed | The instantaneous speed reported from the device at the instance the device recorded the event |
| Trip Odometer | An interpreted value based on Vehicle Speed over Time; units = meters |
| External Battery Voltage | Actively monitored and reported through the A/D wiring/connection of the installation; units = ADC |
| Temperature | The instantaneous temperature reported from a device equipped with a temperature sensor; units = Celsius |
| Instantaneous Fuel Economy | An interpreted value based on ECU Vehicle Speed and ECU Fuel Rate; units = (Tenths of Km)/Liter |
Vehicle Diagnostics
Please see the below table for the vehicle diagnostic type and a corresponding description. This data is directly related to the information voluntarily reported from the vehicle’s ECU or otherwise polled from the vehicle on a predefined schedule.
Vehicle diagnostics reported from the ECU varies from vehicle to vehicle, based on vehicle make/model/year.
| Type | Description |
|---|---|
| Engine Speed | The instantaneous RPM value reported from the vehicle’s ECU at the instance the device recorded the event; units = 0.1 RPM |
| Fuel Level Percentage | Percentage of fuel level remaining; units = 0.01% |
| Fuel Level Remaining | ECU calculation on exact fuel level remaining; units = milliliters |
| Engine Coolant Temp | ECU calculation on exact coolant temperature; units = 1/16 degree Celcius |
| Fuel Rate | ECU calculation on the rate of fuel consumed; units = milliliters/hour |
| Odometer | ECU calculation on the total distance traveled; units = meters |
| Vehicle Speed | ECU calculation on the instantaneous speed reported from the vehicle’s ECU at the instance the device recorded the event; units = centimeters/sec |
| Max Acceleration | The maximum ECU calculated Vehicle Speed increase over a limited and shortened duration |
| Max Deceleration | The maximum ECU calculated Vehicle Speed decrease over a limited and shortened duration |
| Diagnostic Max Speed | The maximum ECU value of Vehicle Speed recorded within a predefined interval |
| Max Vehicle RPMs | The maximum ECU value of RPM recorded within a predefined interval |
| Engine Hours | ECU calculation on the total engine run time; units = 0.05 hours |
| Engine State | The instantaneous engine state value reported from the vehicle’s ECU at the instance the device recorded the event; units = Engine Off, Engine On |
| DTC Count | The instantaneous count of diagnostic trouble codes reported from the ECU at the instance the device recorded the event; units = number of current DTC codes |
| Engine Oil Temperature | ECU calculation on exact engine oil temperature; units = 1/16 degree Celcius |
| Fuel Type | The instantaneous engine state value reported from the vehicle’s ECU at the instance the device recorded the event; units = Not Available, Gasoline, Methanol, Ethanol, Diesel, LPG, CNG, Propane, Electric |
| Hybrid/EV: State of Charge | The percent remaining level of charge; units = 0.10% |
| Hybrid/EV: Current Voltage | The current voltage read from the ECU on an electric or hybrid vehicle; units = Volts/Amps |
| Seatbelt Fastened | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = Yes, No |
| MIL Status | Malfunction Indicator Light (e.g. engine light), the instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = On/Off |
| TPMS Light Status | Tire Pressure Monitor System, the instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = On/Off |
| Hybrid/EV: Charging State | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = Sustaining (charging), Depletion (not charging) |
| Tire Pressure – Left Front | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = kPa |
| Tire Pressure – Left Rear | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = kPa |
| Tire Pressure – Right Front | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = kPa |
| Tire Pressure – Right Rear | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = kPa |
| Turn Signal Status | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = Off, Left, Right, Left & Right |
| Transmission Gear | The instantaneous value reported from the vehicle’s ECU at the instance the device recorded the event; units = Park, Reverse, Neutral, Drive |
*GPS = satellite interpreted data
**Some unit values reported may be converted to larger values or Imperial measurements for easier interpretation