TPMS (Tire Pressure Monitoring System) watches inflation so you do not have to guess. When the light comes on, the system saw a pressure problem, a sensor problem, or both. Clearing it without diagnosing it is how people end up on a spare at midnight.
Direct vs. indirect systems
Direct TPMS uses battery-powered sensors—usually in the wheel—reporting pressure (and often temperature). Indirect TPMS uses ABS wheel-speed data to infer a low tire. Direct systems are more precise; they also mean sensor hardware can fail, get damaged on dismount, or die of old batteries.
Why the light turns on
- Actual low pressure (slow leak, temperature drop, recent service)
- Dead or weak sensor battery
- Damaged sensor after a curb hit or bad dismount elsewhere
- Missing relearn after a tire rotation or seasonal swap
- Aftermarket wheels without compatible sensors
What “relearn” means
After rotating tires or installing new sensors, many vehicles need a relearn so the computer knows which sensor sits at which corner. Procedures vary: dash menus, OBD tools, or hold-to-reset sequences. If someone mounts tires and shrugs at a lingering light, the job is not finished.
Mount + balance without a TPMS check is half a ticket.
What Rimline does on TPMS jobs
- Read pressures cold and compare to the placard.
- Scan sensor IDs and battery health when equipment allows.
- Replace damaged sensors with fitment-correct parts.
- Perform the vehicle-specific relearn.
- Road-check that the light stays off.
Can you drive with the light on?
If the light is on, assume a tire may be low until proven otherwise. Check pressures. If one tire is flat or very soft, fix that first. A light that stays on with correct pressures still needs shop diagnosis—do not ignore it for weeks.