These instructions apply to the Lexus SC Mk2 (Z40) 2001-2011.
For other models, please choose your vehicle here.
The tyre-pressure warning on the Lexus SC 430 (2001–2011) — the Z40 — lights up when the system sees a pressure it thinks is too low, or when it has lost its stored baseline after you’ve adjusted the pressures or changed a wheel. On its own it is not a fault: it simply means the current pressures no longer match the reference the car has memorised, so you need to set the correct pressures and then teach the system a fresh baseline with the TPMS SET button. Here’s how.
How the System Works on the SC 430
The SC uses a direct monitoring system: each wheel carries its own sensor that reads the actual air pressure and radios it to the car. Because the readings are real pressures rather than a calculated estimate, the car needs a stored reference to compare them against. Pressing SET tells it “these pressures are correct — use them as the new baseline.” That is why a reset only works properly once the tyres are actually at the right figures.
Before You Start
- Set the pressures with the tyres cold — after the car has stood for a few hours or been driven only a mile or two.
- Use the figures on the placard in the driver’s door shut, not the maximum moulded into the tyre sidewall.
- Check all four corners, including any that look fine — one soft tyre blocks the reset.
- Have the car parked and level, and know where the SET button is (low on the dash near the steering column) before you begin.
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).
- Turn the ignition on (engine off).
- Press and hold the TPMS ‘SET’ button (low on the dash near the steering column) until the TPMS warning light blinks, then release.
- The system learns the current pressures as the new baseline; it finishes after a short drive.
If the Warning Stays On
- Recheck every tyre — one below spec keeps the warning on and blocks the reset.
- Hold the SET button until the light blinks — releasing early cancels it.
- Drive for a few minutes after pressing SET so the sensors report.
- A cold morning can drop pressure enough to trip the light — top up to the placard figure and reset.
- After a wheel swap the reference must be re-stored; the light will nag until you press SET again.
- One corner that keeps falling points to a slow puncture or a leaking valve rather than a system glitch — inspect the tyre.
- Still showing with correct pressures? A sensor may have a flat battery — look up the code on autodtcs.com.
What to Expect After
Once you’ve held SET until the light blinked and driven a few minutes, the warning should go out and stay off for the rest of the journey. The system keeps watching in the background, so if a tyre later drops below the stored baseline the light returns — that is it doing its job, not the reset failing.
Frequently Asked Questions
How do I reset the tyre pressure light on a Lexus SC 430?
Set all four tyres to the correct cold pressures from the driver’s door placard, switch the ignition on with the engine off, then press and hold the TPMS SET button until the warning light blinks and release. Drive for a few minutes so the sensors report and the light clears.
Where is the TPMS SET button?
Low on the dashboard near the steering column — your handbook shows the exact spot. It is a small dedicated button, not part of the trip or menu controls, so once you know its location the reset itself takes only a few seconds.
Why won’t the warning clear?
Almost always because a tyre is still below spec, or the SET button was released before the light blinked. Recheck all four pressures cold, hold SET until you see the light flash, then drive a short distance. If every tyre is correct and it still shows, suspect a tired sensor battery.
Do I need a tool?
No for a normal reset; a tool is only needed if a sensor is replaced.
Does the light come back on in winter?
It can. Air contracts as it cools, so a tyre set correctly in mild weather can read low on a frosty morning and trip the warning. Top the pressures back up to the door-placard figure with the tyres cold, then run the SET reset again to store the corrected baseline.
Do I have to reset after just topping up one tyre?
It is good practice. The system compares live pressures against a stored reference, so after any change — even a single top-up — pressing SET with all four tyres correct makes sure the baseline matches reality and stops the light returning unnecessarily.
If the warning came on with other lights, decode the code on autodtcs.com.
Independent guide — not affiliated with Lexus. Always follow your official service manual and safety precautions. Read our full disclaimer.