Troubleshooting • TPMS Sensors
TPMS Sensor Not Reading? Here’s Why
If your TPMS sensor is not reading, showing “no signal”, blank data, or a missing tyre, it usually means the sensor has lost communication, the battery is low, or the sensor needs to be re-paired.
This guide explains the most common reasons a tyre pressure monitoring system (TPMS) sensor stops reporting, how to fix it, and when replacement may be required.
Part of the SAVR knowledge hub: TPMS Knowledge Hub. SAVR or Safety Sam owner? The Support Hub has step-by-step fixes for the TPMS Connect app.
Quick Answer
A TPMS sensor usually stops reading because of:
- Sensor not yet fitted or still asleep (it only wakes on a pressurised valve)
- Low or flat sensor battery
- Sensor not paired or assigned to the right wheel
- Signal range issues (common when towing)
- Sensor damage or water ingress
- Valve stem or fitting issue
- App, Bluetooth or profile issue on the phone
1. Low Sensor Battery (Most Common Cause)
Most external TPMS sensors use small replaceable coin-cell batteries — SAVR sensors use a standard CR1632 that lasts 12–24 months. When battery voltage drops, the sensor may transmit inconsistently or stop reporting entirely.
Symptoms include:
- Intermittent readings
- “No signal” warnings
- Fault warnings after driving for a short time
Replace the battery and re-check readings before assuming the sensor is faulty. How to replace a SAVR sensor battery (2 min).
2. Sensor Not Paired or Assigned Correctly
If you’ve rotated tyres, replaced a sensor, or set up a new phone, the app may not have the right sensor on the right wheel.
Re-pair the sensor to the correct tyre position. In TPMS Connect, open the wheel position, choose Scan Pair and scan the barcode on the sensor. A complete 2- or 4-sensor pack can be re-added in one go with One-Click Pairing using the QR card from the box.
Installation help: TPMS installation and setup videos
3. Signal Range Problems (Especially When Towing)
If the sensor that stops reading is on your caravan or trailer, signal range may be the issue. Bluetooth sensors typically reach around 15 metres to the phone.
Causes include:
- Distance between the phone and the rear of the van too great
- Metal structures blocking signal, or the phone sitting low in the cabin
- Weak sensor battery struggling at distance
Mounting the phone higher on the dash or windscreen usually fixes it. For towing setups: Best TPMS for Caravans & Towing
4. Sensor Damage or Water Ingress
Sensors are exposed to road debris, weather, and vibration. Damage can occur from:
- Kerb strikes
- Corrosion
- Water entering the housing
- Overtightening onto valve stems
Inspect the sensor closely. If damaged, replacement may be required.
5. Valve Stem or Air Leak Issue
If the sensor is not sealed properly on the valve stem, you may lose both signal and pressure.
Ensure the sensor is screwed on hand-tight (never with a tool) and that the valve core is intact. Remember that a sensor only wakes up and starts transmitting once it is fitted to a pressurised valve.
6. App or Bluetooth Connection Problem
Sometimes the issue is not the sensor but the phone side.
- Check Bluetooth is turned on and the app has Bluetooth permission
- Make sure the vehicle profile containing that sensor is set to Active
- Restart the app, and check the app is up to date
- Don’t look for the sensor in your phone’s Bluetooth device list — SAVR sensors broadcast to the app and never appear there
What to Do When a TPMS Sensor Stops Reading
- Confirm tyre pressure manually with a gauge.
- Identify which sensor is not reporting.
- Check Bluetooth is on and the vehicle profile is Active in the app.
- Drive a short distance or release a little air to wake the sensor.
- Replace the sensor battery (CR1632).
- Inspect for visible damage.
- Re-pair the sensor with Scan Pair.
- Test by driving for several minutes.
If the problem only happens at highway speeds: Why Does My TPMS Go Off on the Highway?
When Should You Replace a TPMS Sensor?
Replace the sensor if:
- Battery replacement does not restore signal
- The housing is cracked or corroded
- It repeatedly drops signal despite correct setup
SAVR sensors carry a 2-year warranty (12 months for Safety Sam purchases) — a sensor that won’t read after these steps is usually replaced without you sending it back. Warranty details.
Need a replacement or an extra sensor? SAVR Tyre Pressure Monitoring System
FAQs
Why is only one TPMS sensor not reading?
Most often due to low battery, sensor damage, or pairing issues specific to that wheel. If the other sensors are working, the phone and app are fine — focus on that sensor.
Can a dead battery cause a TPMS sensor to stop reading?
Yes. A flat battery is one of the most common reasons for “no signal” warnings.
Why doesn’t my TPMS sensor show up in my phone’s Bluetooth list?
Because it isn’t meant to. Broadcast-style Bluetooth sensors like SAVR’s are paired inside the TPMS app, not in the phone’s Bluetooth settings.
Do I need to replace the whole TPMS if one sensor fails?
No. Individual sensors can usually be replaced without replacing the entire system.
