TPMS Warning Light: Complete Guide
What to do when your Tire Pressure Monitoring System warning light comes on, common causes, and how to reset it properly.
⚠️ Safety First
A TPMS warning light indicates at least one tire is significantly under-inflated. Do not ignore it. Low tire pressure can lead to tire failure, poor handling, and increased risk of accidents.
What Does the TPMS Light Look Like?
The TPMS warning light typically appears as one of these symbols on your dashboard:
Exclamation Mark Symbol
Cross-section of tire with exclamation mark inside
TPMS or "Low Tire" Text
Some vehicles display "TPMS" or "Low Tire Pressure" text
What the Light Means
🔴 Solid Light (Steady)
Meaning: One or more tires are 25% or more below recommended pressure
Action: Check tire pressure immediately and inflate to proper level
⚡ Flashing Light (Blinking)
Meaning: TPMS system malfunction or sensor failure
Action: Have system diagnosed by a professional - sensors may need replacement
Common Causes
1. Temperature Change
Most Common Cause (60-70% of cases)
Cold weather causes tire pressure to drop. A 30°F temperature drop can reduce pressure by 3-4 PSI, enough to trigger the warning light. This is especially common on the first cold morning of fall/winter.
2. Slow Leak
Second Most Common (15-20% of cases)
Small punctures from nails, screws, or road debris can cause gradual air loss. You might not notice the flat until the TPMS alerts you.
3. Natural Air Loss
Maintenance Issue (10-15% of cases)
Tires naturally lose 1-2 PSI per month through normal permeation. If you haven't checked pressure in several months, it may drop below the TPMS threshold.
4. Sensor Malfunction
System Failure (5-10% of cases)
TPMS sensors have batteries that typically last 5-10 years. Dead sensor batteries cause the light to flash, not display solid.
What To Do When Light Comes On
Immediate Actions (Within 24 Hours)
- 1.Pull Over Safely
If light comes on while driving, find a safe place to stop and visually inspect all tires for obvious damage or flat appearance.
- 2.Check All Four Tires
Use a tire pressure gauge to check each tire when cold. Compare readings to the recommended pressure on your door jamb sticker.
- 3.Inflate to Proper Pressure
Add air to any tire that's below specification. Check your spare tire too while you're at it.
- 4.Drive and Monitor
The light should turn off after driving 10-20 minutes if pressure is correct. If it stays on, there may be a leak.
How to Reset TPMS Light
Most vehicles reset automatically:
- ✓ Inflate all tires to correct pressure
- ✓ Drive at 50+ mph for 10-20 minutes
- ✓ Light should turn off on its own
Manual Reset Methods
If the light doesn't turn off automatically, try these methods (varies by vehicle):
Method 1: TPMS Reset Button
Some vehicles have a TPMS reset button (usually under steering wheel or in glove box). Press and hold for 3 seconds with ignition on, engine off.
Method 2: Tire Pressure Menu
Navigate to tire pressure settings in your vehicle's information display and select "Reset" or "Initialize."
Method 3: Drive Cycle
Drive at various speeds for 20-30 minutes. Many systems reset after multiple drive cycles.
Method 4: Battery Disconnect
Disconnect car battery for 15 minutes (last resort - may reset other systems).
When to See a Professional
Visit a mechanic if:
- ❌ Light stays on after proper inflation
- ❌ Light is flashing/blinking
- ❌ Tire loses pressure repeatedly
- ❌ Visible tire damage or bulge
- ❌ Light won't reset after multiple attempts
- ❌ One tire pressure drops faster than others
TPMS Sensor Replacement
TPMS sensors typically need replacement every 5-10 years when batteries die:
| Service | Typical Cost | Notes |
|---|---|---|
| Sensor Replacement (1 tire) | $50-$150 | Parts + labor |
| All 4 Sensors | $200-$500 | Recommended to replace all at once |
| Sensor Programming | $25-$75 | Required after replacement |
Prevention Tips
Prevent TPMS warnings:
- ✓ Check tire pressure monthly (don't rely on TPMS alone)
- ✓ Check before temperature changes (fall/winter transition)
- ✓ Maintain proper pressure year-round
- ✓ Inspect tires regularly for damage
- ✓ Replace tires before tread is too worn
- ✓ Have TPMS system checked during tire rotation
Common Myths
❌ Myth: "I can ignore it if tires look fine"
Reality: You can't see a 5-8 PSI loss visually. The TPMS activates at 25% below spec, which is dangerous.
❌ Myth: "TPMS replaces manual pressure checks"
Reality: TPMS only warns when pressure is critically low. Check manually monthly.
❌ Myth: "Over-inflating prevents the warning"
Reality: Over-inflation causes uneven wear and harsh ride. Use recommended pressure only.
Key Takeaways
- ✓TPMS light means at least one tire is 25% or more below recommended pressure
- ✓Check and inflate all tires immediately when light comes on
- ✓Temperature changes are the most common trigger
- ✓Don't rely on TPMS as your only pressure monitoring - check monthly
- ✓Flashing light indicates system malfunction - see a professional