Incorrect GO device ignition status

Learn how the GO device detects ignition and why the reported state may be wrong.

Ignition status supports tracking and monitoring in MyGeotab. A GO device may sometimes report the wrong state when the vehicle's ignition is turned on or off.

Engine-based detection

Engine-based detection is the primary and most accurate method. The GO device initially powers on through a voltage spike or movement detected by its accelerometer. Once active, it analyzes data from the vehicle's electronic control unit (ECU), such as RPM (revolutions per minute) or engine road speed, to determine whether the engine is running.

This method depends on communication with the ECU through protocols such as OBD, J1939, or J1708. A lack of this communication is the most frequent reason for ignition-detection failures.

Three-wire harness connection

A three-wire harness uses a dedicated third wire in the harness to send the vehicle's ignition state directly to the GO device. This provides a reliable, direct signal.

Trip tracking and two-wire logic

When the device cannot obtain engine data, or has only two wires for power and ground, it uses less precise methods:

  • Trip tracking infers ignition from vehicle movement and activity. If the vehicle remains stationary for more than 200 seconds, the device typically registers ignition as off.

  • Two-wire logic is a custom parameter that uses voltage fluctuations in a two-wire installation to infer ignition status.

Causes of incorrect ignition readings

  • Incorrect wiring or loose connections can disrupt signals to the device.

  • Physical damage to the device or harness can impede communication.

  • Vehicle kill switches can interfere with ignition readings.

  • A two-wire installation does not receive direct ignition status from the ECU and uses less accurate inference methods.

  • An incompatible ECU communication protocol can prevent data exchange.

  • An intermittent connection to the engine diagnostic port can cause sporadic or incorrect readings.

  • The Keep Ignition On parameter prevents the device from entering Sleep mode and makes it continue to report ignition as on when the vehicle is off. It does not keep the vehicle's actual ignition on and can drain the battery if used inappropriately.

Effects of inferred ignition status

If a vehicle is known to have engine-based or three-wire ignition capability but does not report it, Trip Tracking may register ignition as on based on accelerometer-detected movement or when GPS is powered on for a certain period.

In a two-wire installation, the device averages voltage and sets ignition to on when voltage reaches a specific threshold. Movement or voltage changes, such as when a vehicle is on a boat or being towed, can be misinterpreted as ignition being on.

To investigate incorrect readings, follow Checking GO device ignition detection.

Checking GO device ignition detection

Check wiring, engine data, and device settings when the GO device reports the wrong ignition state.

Before you begin: The checks in MyGeotab require the necessary permissions. If access is limited, contact the Administrator or the authorized Partner that provided the device.

Use these checks when ignition status is not reported accurately. Refer to Incorrect GO device ignition status for the detection methods and their limitations.

  1. Inspect all wiring and connections to confirm they are secure and correct.

    Confirm the device is firmly installed and has no signs of physical damage. Check for aftermarket kill switches that could interfere with device operation.

  2. In MyGeotab, check whether the device receives other engine data, such as RPM and speed.

    Follow Viewing measurements. If no engine data is present, this indicates a communication issue with the ECU. Look for Listen-only mode under Engine Faults; this suggests an intermittent connection. Follow Viewing fault details.

  3. If possible, test another compatible device in the same vehicle.

    If another compatible GO device is available, try installing it in the same vehicle to determine whether the issue is with the original device or the vehicle configuration.

  4. Determine whether the device uses a two-wire or three-wire harness.

    This affects how ignition status is determined.

  5. Review the device parameters in MyGeotab for the Keep Ignition On setting.

    If the setting is enabled and is not required for the intended use, consider disabling it.

  6. After confirming the device is securely and correctly installed, power cycle it to check whether this resolves intermittent connection issues.

    For the physical restart procedure, follow Restarting the GO device.

Next steps: To disable two-wire logic and trip tracking for a specific vehicle, add this custom parameter in MyGeotab:

If the checks do not resolve the issue, follow the guidance for Contacting Support.