Whether the Data Is Any Good

Telematics reports confidently whether or not it is working. These four checks take an afternoon and are worth repeating quarterly.

Reporting coverage

Proportion of operating time with data arriving, per vehicle.

A vehicle consistently below the fleet average has a device fault, a wiring problem or a disconnected dongle — and checking that before anything else avoids an unfortunate conversation.

A fleet-wide drop usually follows a firmware update or a network change.

Odometer agreement

The telematics odometer against the vehicle's own, read at service.

They diverge, and the size of the divergence tells you whether distance-based decisions are safe.

A large or growing gap means the device is calculating rather than reading, which is common on dongles and matters for maintenance intervals.

Record the comparison at every service, which costs nothing and builds the evidence.

Fuel figures against fills

Consumption reported against litres purchased, over a quarter.

A persistent gap is either a metering issue, a leak or fuel going elsewhere, and the three are distinguishable by whether it is one vehicle or a site.

Where the vehicle estimates rather than measures consumption, the figure is indicative only and should be labelled as such in any report.

Vehicle identity

Does the device record match the vehicle it is fitted to?

Devices get swapped between vehicles during repairs and nobody updates the register.

Compare device assignments against the fleet list quarterly.

Where mismatches are common, per-vehicle analysis is unsupportable — and that is worth knowing before a replacement decision is made on the wrong vehicle's history.

Reporting the four

Alongside any analysis, so a reader knows what weight to apply.

With the data source stated, because a figure read from the CAN bus and one estimated by a dongle are not the same quality.

And with known gaps named.

Acting on them

Coverage low: check the device first, then the wiring, then the vehicle's usage pattern.

Odometer diverging: switch the maintenance trigger to the vehicle's own reading until it is resolved.

Fuel gap: investigate the vehicle, not the driver, first. It is a fault more often than anything else.

Identity mismatched: fix the register before trusting any per-vehicle figure, and say that you are doing so.

Compare odometers at every service

A check that costs nothing and builds evidence.

The telematics figure against the vehicle's own, recorded on the job sheet.

Divergence tells you whether distance-based decisions are safe.

A growing gap means the device is calculating rather than reading, which is common on dongles and matters directly for service intervals.

Turn the boundary into a test

For a concrete product reference, use this boundary reference can help turn this boundary into a test. Verify the current behaviour with representative fields and record what reaches the destination.

Independent reference

For a thematic point of reference, see the International Organization for Standardization. This popular specialist site offers a useful independent reference for the issue.