These instructions apply to the Subaru Legacy Mk6 (BN) 2014-2019.
For other models, please choose your vehicle here.
When the tyre-pressure warning appears in your Subaru Legacy (2014–2019) — the BN B4 — it is usually the car telling you a tyre has read low against the pressure it expects, not that something has failed. On a saloon that covers plenty of motorway miles, the light most often shows up after a cold spell, when a tyre has quietly lost a few psi over time, or straight after you have adjusted the pressures or changed a wheel and the system is still working from the old figures. Set the pressures correctly, drive far enough for the Legacy to re-read them, and the warning switches itself off. The steps below walk through it.
How the Legacy monitors pressure
The car keeps track of each wheel and lights the warning when a tyre falls roughly below the value on the driver’s door-pillar placard. On this generation the light is cleared from the corrected pressures, not from a stored button-press, so there is no on-screen “reset” routine to find — the whole reset is getting the four pressures right and letting the car read them on a short drive. That is why an accurate gauge and the correct target figure matter more than any menu.
Before You Begin
- Check the tyres cold — stood for at least three hours, or driven under a mile. Warm tyres read high and hide a soft one.
- Use the placard figure in the driver’s door shut, not the maximum stamped on the tyre sidewall.
- Set every corner, including the tyre that raised the warning, with a trustworthy gauge.
- Include the spare if a full-size wheel is currently fitted on the road.
- Do it on level ground so the car is settled before you drive.
When to Reset
- After checking or adjusting the tyre pressures.
- After changing wheels or tyres, or fitting winter wheels.
Resetting the System
- Park level and set all four tyres to the correct cold pressures (placard in the driver’s door shut).
- Drive the vehicle for about 10 minutes at over 40 km/h (25 mph).
- The system relearns the corrected pressures and the warning clears.
If the Warning Won’t Clear
- Recheck all four — a single tyre still a little low will keep the light on even when the others are spot on.
- Extend the drive — a brief trip may not let the system settle; a steady run of several minutes is more reliable.
- Cold weather lowers pressure; on a frosty morning re-inflate to the placard figure with the tyres cold.
- Slow leak — if one tyre keeps dropping, look for a nail or a leaking valve instead of resetting repeatedly.
- Space-saver spare? It runs at a much higher pressure, and the warning can stay on until the standard wheel goes back.
- Faulty sensor — a wheel sensor with a flat battery or a damaged valve can hold the light on despite correct pressures. Any stored code can be checked on autodtcs.com.
After the Reset
Once the pressures are correct and you have driven for a few minutes, the warning should go out and stay off for the journey. If it clears and then returns a day or two later, that behaviour usually means a slow leak rather than a glitch — get the tyre checked. A quick flash of the symbol at start-up that then disappears is just the normal self-test.
Frequently Asked Questions
How do I reset the tyre pressure light on a Subaru Legacy?
There is no button to press on this generation. Inflate all four tyres to the cold pressures on the driver’s door-pillar placard, then drive for around ten minutes above 40 km/h. The Legacy re-reads the corrected pressures during the drive and clears the warning on its own.
The tyres are pumped up but the light stays on — what now?
Typically one corner is still below target, or the learn drive was too short. Recheck every tyre cold with an accurate gauge, correct anything low, and drive a bit further. If all four are genuinely right and it persists, the likely causes are a slow leak or a wheel sensor.
Do I need any special tools?
No — a normal reset needs only correct pressures and a short drive. A diagnostic tool is only required if a wheel sensor has been replaced and must be registered, or if you want to read a stored fault code.
Can a cold morning trigger the warning?
Yes. Tyre pressure drops with temperature, so the first cold days of the season often set the light off even on sound tyres. Top the pressures back up to the placard figure while the tyres are cold and the warning should clear on the next drive.
Why does the light return after I clear it?
A warning that keeps coming back after being reset generally indicates a slow puncture in one tyre — a nail, a porous rim, or a weeping valve. Recheck that tyre and inspect the tread and valve. Resetting again without repairing the leak simply hides it.
Do I need to reset after swapping to winter wheels?
Set the winter wheels to the correct cold pressures first, then drive so the system re-reads them; a full-size winter set works like the normal wheels once inflated properly. The temporary space-saver is different — it runs much higher and the light may stay lit until the road wheel is refitted.
If the tyre-pressure warning appeared with other dashboard lights, decode the stored trouble code on autodtcs.com before assuming it is only a pressure issue.
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