A TPMS is not finished when the boxes are fitted
Most fleet TPMS projects fail in the week after installation, not during it. The hardware is on
the wheels, the receiver is wired, and then someone notices that two positions are missing, that one
trailer drops out when it is parked at the far end of the yard, or that nobody wrote down which
sensor ID went on which wheel. Six months later a sensor fails and no one can say which position it
was.
This is a commissioning checklist — the steps that turn "we fitted it" into "we can trust it". It is
written from the receiver side, which is where our work starts, but the order applies to any
commercial-vehicle system.
1. Before anything is fitted
Agree the wheel map first. Draw the axle layout and number every position. On a tractor unit
that is straightforward; on a trailer with a spread axle or a heavy transporter with 10+ axles it is
the only way to keep the record straight. Everything later — pairing, alarms, the handover document
— refers back to this map.
Decide where the data ends. Cab display, vehicle controller, or platform. This decides the
receiver type and whether a gateway is needed, and it is much cheaper to decide now than to change
later. If the answer is "the controller", confirm which bus it exposes and ask for the message map
in writing before the hardware ships — a receiver that publishes CAN without a documented layout is
not integrable, it is a promise.
Check the valve situation on one wheel before buying sensors. External sensors need an
accessible valve; internal band sensors mean the tyre comes off. Mixing the two on one vehicle is
possible but should be a decision, not a discovery.
2. Pairing and the ID record
Pairing itself takes a minute per sensor. The record is the part people skip.
For every wheel position, write down: position number, sensor ID, sensor type, battery type, and the
date. Keep it as a spreadsheet that is versioned, not as a photo of a screen. Two reasons: when a
sensor dies you know which position it was without re-learning the whole vehicle, and when a vehicle
changes hands the next workshop has something to work from.
If your tooling supports it, print the map and tape it inside the cab or in the maintenance folder.
Paper survives a dead laptop.
3. Receiver placement and the coverage test
Receiver placement is a radio decision, not an electrical one. Steel blocks the signal, so the
receiver wants to be near the wheels it is serving, with the shortest path through air — not tucked
behind a chassis member because the cable was shorter there.
Then test coverage the honest way: park the vehicle where it will actually stand, and read every
position. Not in the workshop with the doors open. A layout that works in the bay and drops one
position in the yard is not a working layout.
On long combinations, this is where a repeater is decided. Repeaters are not an upsell; they are
coverage. A system that drops frames is worse than no system, because people stop trusting it.
4. Bus verification
If the receiver talks to a controller, verify at the controller — not at the receiver's LED.
- Read the actual values at the controller and compare them against a calibrated gauge on the same
wheel. A few kPa of difference is normal; a systematic offset is not.
- Confirm the cycle: our receivers publish on a 500 ms cycle, and the sensor itself reports on a
slower configurable interval. If the controller expects a value every 100 ms it will see stale
data and may alarm.
- Confirm the frame format: 11-bit or 29-bit extended, and the bitrate. These are factory settings
and mismatches look like "the receiver is dead".
- If the interface is Modbus RTU, remember the receiver is a slave: it answers, it does not
push. Polling rate belongs to your master.
5. The baseline record (the step that pays later)
Record, on day one: every tyre's pressure and temperature, the ambient temperature, the load state
(empty or loaded), and the gauge used. Then do the same a week later.
That pair of records is what makes every later alarm meaningful. Without a baseline, "pressure
dropped 40 kPa" is a number; with one, it is a leak, a temperature effect, or a sensor drifting.
6. Handover
Give the operator three things: the wheel map with IDs, the alarm thresholds in plain language, and
one sentence about what to do when an alarm appears. Most "the system does not work" complaints
are actually "nobody told the driver what the beep means".
What goes wrong when the checklist is skipped
Three failures account for most of the complaints we hear after a rollout:
A position that never reports. Almost always the sensor was paired but the ID was recorded
against the wrong wheel, or the receiver sits behind steel relative to that one position. Both are
invisible until someone compares readings against a gauge, which is why step four exists.
A trailer that drops out in the yard but works in the bay. A coverage problem, and it is
predictable: park the vehicle where it will actually stand during the test.
An operator who ignores the alarms. The thresholds were never explained, so every beep became
noise, and after two weeks nobody looks at it.
None of these is a hardware fault, and none of them is fixed by better sensors.
If your measuring point is not a tyre
The same commissioning logic applies to pressure sensing on gas circuits away from the wheels. We
cover three of those cases on their own pages: [wireless air spring pressure
sensor](https://gzvia.com/air-spring-pressure-sensor) (5-10 bar, no wiring on the axle),
remote pneumatic shaft pressure monitoring
(7 bar gas, early leak detection), and a [Bluetooth pressure sensor with no
receiver](https://gzvia.com/bluetooth-pressure-sensor) for on-demand checks.
A short version for a single vehicle
If you are commissioning one truck rather than a fleet: draw the map, record the IDs, place the
receiver near the wheels, test where the vehicle parks, verify one value at the controller against a
gauge, and write the baseline down. That is half a day and it saves the arguments.
See the receiver and sensor configurations on the product pages, the interface options
on the TR100 receiver page, and how our sensors and receivers are used on
trailers and multi-axle combinations. If you want the integration
detail, the DBC and message-map page covers what we hand over. If you want this checklist turned into a template for your own wheel map, send us the layout.