Tire Pressure Sensors on an Aston Martin DB9

Aston Martin DB9 Tire Pressure Sensor TPS
Yellow banded left rear TPS

The DB9 is equipped with a Tire Pressure Monitoring System (TPMS) that includes Tire Pressure Sensors (TPS) mounted to each wheel.  They are an integral part of the air valve.   You’ll notice that each of your air valves has a colored ring around it, either Red, Green, Blue or Yellow.   In your trunk / boot is a mysterious little box with LEDs.  This is the TPMS indicator panel, and if you ever get a warning indication on the dash, you’ll need to check the LED’s and see which color is lit, and that’s the tire with the issue.

During service the main thing we can do is make sure the correct sensor is on the correct wheel.  The documentation says the TPMS is expecting them in these positions:

  • Yellow – Left Rear
  • Red – Left Front
  • Green – Right Front
  • Blue – Right Rear

It is possible that during a set of new tire installations or service a tire technician could have missed this detail, and installed them on the opposite sides.  It’s easy to check, so have a look.

If you find them out of place, be careful to avoid just swapping the rim and tire to the other side.  Remember these tires are unidirectional, and if you move the right front to the left front, the tire will now be spinning in the opposite direction than it was, and this is not good.   You actually need to have the tires dismounted and remounted (and rebalanced) as you swap rims (the right front tire needs to always be on the right front after you’ve driven on it a few miles).

TPMS Alerts:

Low Tire Pressure Warning IconThe TPMS does more than just report the current tire pressure, it actually alerts us to three conditions:

Low Tire Pressure

If the tire pressure is below 30 psi it will alert us.

I get this alert occasionally as the seasons change from Summer (where I live it gets to 100°F) to Winter (as cool as 32°F).  This ambient temperature change is enough to drop the cold resting temperature of the tire a few psi, so it sets off the alert and I get off my ass and set my tire pressures for the season.   Remember to reset the tire pressures at least once per season.

High Tire Temperature

If a tire is above 170°F it will alert us.  This could happen if you are pushing your tires very hard (on a track) and they are overheating, or if they are dangerously low and they are overheating due to sidewall flex.  Either condition is dangerous and you should stop and deal with it appropriately.

Pressure Change

If a tire goes through a 5 psi pressure change during a driving session it will alert us.  This is to catch a leak that’s just started before we get into trouble.  For example, if your tire was 38 psi when you started a trip and you picked up a nail and a leak, it will go into alarm at 33 psi during the same trip.

Here is a quick video about this.

You might want to check out these other posts relating to your tires:

4 thoughts on “Tire Pressure Sensors on an Aston Martin DB9

  1. Martin Murphy

    Hi Steve, There is one more reason why the dash amber light will come on:- If you have changed a sensor due to it getting broken when changing tyres etc. Then it will need re-coding to the car. That is why I found your piece, I need to re-code and don’t want to go to my Aston Dealer because it’s inconvenient and probably costs a lot. The sensors are Smartire Systems and don’t appear to have colour code bands.

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    1. Thanks for the note. The official Aston Martin Workshop Manual has a section on it (4.04) and it requires a special Smartyre Display unit tool. You would plug this into the sending unit in the trunk (boot) and then follow the procedures for “Transmitter Learn Mode” to delete the damaged transmitter and then add the replacement. It looks like Smartire is no longer selling automotive products (see http://www.smartire.com/automotive). This website seems to know a lot about TPMS tools and learning https://www.tpmswarehouse.co.uk/blog/tpms-relearn/.

      A little Googling turned up the Aston Martin tool as a Smartire ST2 unit. I found the manual online for the ST-2 Full Function Display http://www.smartire.com/2006/pdf/manuals/full_func_display_english.pdf. The Aston manual describes what Smartire calls the full function remote display. I couldn’t find any for sale on eBay or Amazon, but at least you know what you are looking for. You might contact those TPMWarehouse folks and ask them if they have another controller that can program the unit – I bet they do. Let me know what you learn

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  2. jordan

    I am in looking into this an may need to replace the TPMS units — how do I find out which frequency units I need to order as there are 2 part numbers that come up thanks

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  3. Roger Smith

    Hi I have a question regarding flashing amber lights on the smart tire unit under the glove box. All five are flashing but there is no amber tyre symbol on the dashboard, why would that be ? A friend of mine with a similar car has the same system but the first light is solid green and the other 4 are not lit or flashing

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