Symptom guide
TPMS Light On
What TPMS does
The Tire Pressure Monitoring System measures pressure in each tire via a sensor mounted inside the wheel (direct TPMS) or estimates from wheel-speed differences (indirect TPMS).
Direct TPMS (most modern vehicles): sensor on each wheel transmits actual pressure to the receiver. The light triggers when one or more tires drop below threshold.
Indirect TPMS (some platforms): system compares wheel rotation speeds. A low tire spins faster than its mates; the system flags the difference.
Steady light vs blinking light
- Steady on: one or more tires below threshold. Action: check and add air.
- Blinking (60–90 seconds), then steady: TPMS system fault. Action: diagnose the system (failed sensor or receiver).
What to do right now
Step 1: Check all four tire pressures
Use an accurate digital gauge. Compare against the door jamb sticker (not the tire sidewall). Note any tires below spec.
Step 2: Add air to specified PSI
Top up to the door jamb spec. Don't over-inflate.
Step 3: Drive 5–10 miles
The TPMS receiver re-reads pressures periodically. After topping up, drive a few miles and check if the light turns off.
Step 4: If light stays on
Possible causes:
- One tire wasn't filled enough.
- A sensor has failed.
- The system needs a reset procedure.
Common causes ranked
1. Actually-low tire (~70%). Tire pressure dropped below threshold. Action: add air.
2. Cold-weather pressure drop (~10%). 1 PSI per 10 °F drop. Common in fall. Action: top up.
3. TPMS sensor battery dying (~15%). Sensor batteries last 5–10 years. Action: replace sensor.
4. Slow leak (~3%). Tire that keeps losing pressure even after top-ups. Action: dismount tire, find puncture or valve leak.
5. TPMS receiver fault (~2%). Rare. Action: shop diagnostic.
Reset procedures by manufacturer
After adding air, some vehicles require a manual reset:
- Honda Civic 2015: Settings menu > TPMS calibration > Initialize.
- Toyota Camry 2018: Settings menu > Vehicle > TPMS > Calibration.
- Ford F-150 2017: Steering wheel buttons > Settings > Vehicle > Reset TPMS.
- Most platforms: drive 5–20 mph for 10 minutes after top-up; the system relearns automatically.
Specific procedure varies — check your owner's manual.
When to replace TPMS sensors
- Battery dying: sensors are sealed; battery isn't replaceable separately. Replace the whole sensor.
- Cost: $30–$150 per sensor + $20–$40 mount/balance.
- All four at once: if one is dying, the others typically follow within 6–18 months. Many tire shops recommend replacing all four with new tires (at 70k–100k miles).
Fixes
| Fix | Cost (USD) |
|---|---|
| Add air | $0–$2 (gas station) |
| TPMS system reset | $0 (DIY procedure) |
| Replace one sensor | $30–$150 + $20–$40 mount |
| Replace all four sensors | $120–$600 + $80–$160 mount |
| Repair tire puncture | $20–$40 |