Tyre Pressure Monitoring Systems (TPMS) warn you when a tyre is under-inflated - often before you feel it in the steering. Replacing a sensor sounds straightforward until you discover that frequency, protocol, valve stem design, and programming all vary by make, model, and market. This guide explains how TPMS works on UK and European cars, how OE part numbers and cross-references fit together, and how to order the correct sensor first time.
What TPMS does
Each monitored wheel reports air pressure (and on many systems, temperature) to the car’s body control module. If pressure drops below a calibrated threshold - often around 20-25% below the recommended cold pressure - a warning lamp appears on the dashboard. The goal is early warning: under-inflation increases fuel use, wears tyres unevenly, and raises the risk of blowouts at motorway speeds.
On UK cars registered from November 2014, TPMS is part of the MOT test where fitted. A permanently lit TPMS warning can fail the test even if tyre tread is legal.
Direct vs indirect TPMS
Direct TPMS
A battery-powered sensor sits inside the wheel - usually clamped to the valve stem or band-mounted on the rim. It transmits a radio signal with pressure data. This is standard on most European cars from the late 2000s onward. When garages say they need to “programme” or “clone” a sensor, they almost always mean direct TPMS.
Indirect TPMS
The car compares wheel rotational speeds via ABS sensors. A soft tyre has a slightly smaller effective rolling radius and spins faster. No sensor in the wheel, but calibration is required after tyre changes and the system is less precise. Common on some older BMW and Volkswagen setups; less common on brand-new models.
433 MHz vs 315 MHz - UK vs US
Direct sensors transmit on a fixed radio frequency. UK and European vehicles overwhelmingly use 433 MHz. North American vehicles typically use 315 MHz. A sensor with the wrong frequency will never be received - no amount of relearn will fix it.
- UK / EU market car: assume 433 MHz unless you know the car was imported from the US or Japan with US-spec hardware.
- Japanese domestic market (JDM) imports may use 315 MHz on some models - check existing sensor label or supplier data.
- Grey imports and ex-US military vehicles are frequent sources of wrong-frequency orders.
Right-hand drive vs left-hand drive does not determine frequency; market of manufacture and sensor part number do.
Who makes OEM sensors
Car manufacturers rarely build sensors themselves. Common OEM suppliers include:
- Schrader (Sensata) - widely used across European marques; often branded Schrader on the valve stem.
- HUF / Continental - common on BMW, Mercedes-Benz, Audi, and VAG group vehicles.
- TRW / ZF - appears on various Ford, Stellantis, and premium applications.
- Pacific Industrial / others - secondary sources on some Asian marques.
Aftermarket “cloneable” or pre-programmed sensors emulate these protocols. Quality units work well when matched correctly; budget unbranded sensors may fail early or not hold programming after relearn.
OE part numbers and cross-reference
Each marque uses its own numbering. Examples you may see on invoices, ETKA, or the sensor body (always verify against your exact vehicle):
| Marque | Example OE references | Notes |
|---|---|---|
| BMW / MINI | 36106881890, 36106859557, 6855538 | Generation and protocol differ - F-series vs G-series not interchangeable. |
| Mercedes-Benz | A0009053100, A0009051714, A0009056100 | Rubber vs metal valve and snap-in vs clamp-in vary by wheel type. |
| Audi / VW / Skoda / SEAT | 5Q0907275B, 7PP907275F, 1K0907275B | MQB platform sensors are not backward-compatible with all PQ models. |
| Land Rover / Jaguar | LR086929, T2H14245, C2Z15278 | Aftermarket wheels may use universal valves - sensor type still must match ECU. |
Supplier cross-reference charts map OE numbers to aftermarket SKUs (e.g. Schrader XX-xxx). Two different OE numbers can point to the same physical sensor after a supersession; conversely, similar-looking sensors may use incompatible protocols. Registration lookup is a starting point - sensor part number from the old unit or a tyre shop scan tool is better confirmation.
When you need a new sensor
- Internal battery exhausted - typical life five to ten years; warning may appear before the tyre looks flat.
- Physical damage during tyre fitting (over-torqued nut, broken stem).
- Corrosion on metal-stem sensors in coastal or winter-salt areas.
- New wheels requiring a different valve design (clamp-in vs snap-in).
- Persistent warning after puncture repair near the sensor.
Replacing all four at once is not always necessary - replace the failed unit or any damaged during service. Some owners refresh all sensors when fitting new tyres on an older car to avoid repeat garage visits.
Programming and relearn procedures
After installation, the car must learn the sensor IDs. Methods vary:
- Auto-learn via drive cycle - some US and Asian models learn after a prescribed speed/distance.
- OBD diagnostic tool - common for BMW, Mercedes, VAG - writes sensor IDs to the module.
- TPMS trigger tool - wakes each sensor in sequence while the vehicle is in relearn mode.
- Indirect reset - iDrive or cluster menu “Reset TPM” after setting correct pressures - no new sensor involved.
A correct sensor that is not relearned will still trigger a warning. If your garage says the sensor is “wrong” after fitment, ask whether relearn was completed before assuming a parts mismatch.
Ordering from Automotive Outlet
We stock TPMS sensors for popular marques in our eBay range and on this site. For best results provide:
- Registration or VIN
- Photo of the existing sensor label (frequency and part number if visible)
- Whether the car is UK-spec or import
- Metal vs rubber valve and snap-in vs clamp-in if known
If you are booking a tyre or wheel change, order the matched locking wheel bolt key at the same time if you are unsure where it is. Garages cannot remove wheels without it.
Changing wheels at the same time? Order your locking wheel bolt key before the appointment so tyres can be removed without delay.
FAQ
- Can I swap sensors from another car?
- Only after reprogramming to your vehicle’s IDs. Unprogrammed used sensors will not work plug-and-play.
- Tyre pressures are correct but the light is on - faulty sensor?
- Often yes, or relearn was skipped. Confirm pressures cold, then diagnose the sensor before replacing tyres.
- Do foam tyres or sealant damage sensors?
- Run-flat sealant can clog or corrode valves; tell the fitter if sealant was used.
- Is TPMS the same as wheel bolt security?
- No - separate systems. We cover wheel security in our locking bolt guide.
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