So this post is because one day I got into my car and discovered I couldn’t adjust my drivers seat. Specifically:
- I couldn’t adjust the seat back incline forward or back
- I couldn’t adjust the seat bottom backwards – BUT – I could move it forward.
- I couldn’t adjust the seat bottom back down – BUT – I could raise it.
- I couldn’t adjust the seat bottom front down – BUT – If I tried to raise it I could hear a motor click. It was already all the way up.
What really sucked is that every time I fiddled with it, I would end up edging the seat forward a bit, and seat bottom back up a bit (the only two motions that worked). Envision me slowly tipping up and squishing into the steering wheel.
Here is a video of the problem in action:
The Search for a Solution
So, I started to look for a solution. I peered under the seat and made sure all the wiring connections were plugged in tightly and that there wasn’t some object stuck under the seat (water bottle, etc). No luck.
I was pretty sure I didn’t have a blown fuse since my seat still moved in two directions. If you seat doesn’t move at all or even click, you should check the fuse.
A post of a similar issue over on 6Speed suggested various things which got me looking into the Seat Module Calibration.
What is a Seat Module?
Each power seat in your DB9 has a Seat Module. The seat module is a physical device mounted under each seat. The module’s job is to operate the seat, and part of that responsibility is to know how far each of the power adjustments can move, forward or back, up or down etc. The seat motors are kind of dumb (just move one way or the other) and it’s the modules job to keep track of the position using a position encoder. Think of it as “Once I know I am at one end of the hall, I know it takes 27 steps to get to the other end”.
Why does it need to be Calibrated?
The problem with the Seat Modules is that they can loose their memory of where “the end of the hall” is. ANY interruption in electricity to the seat module will cause it to forget. Unlike the storage in your cell phone, tablet or PC – if the memory in the Seat Module loses power it’s instantly blank again. Even a dip in the voltage (low battery) might cause it to forget. Stupid design that would be rectified in later model years.
Once the calibration is lost, the seat module automatically goes into calibration mode (to prevent walking into the wall at the end of the hall). Until you complete the calibration, the seat will act weird just as mine was doing above.
Your seat might lose power for several reason:
- You disconnect the battery during a service
- You accidentally drain the battery (dead battery) by leaving the lights on, etc.
- Weak/old battery that needs replaced
- You press the Battery Disconnect Switch (BDS) in the trunk (boot) – this cuts off the power to many of the cars systems including the seat modules.
Aston Martin released Service Bulletin SB153 in December 2004 about each of the modules in the car that need reprogramming after losing power for any reason, and this step is one of them. You can read SB153 here.
Is this a bad thing?
Your car isn’t broken, and the module isn’t bad. This is just a design quirk.
[Well, probably not broken – Aston Martin released Service Bulletin SB202 in July 2006 stating that if you have repeated episodes where the seat calibration is lost (and not related to a power loss) the seat module should be replaced. If your car was under warranty and this was happening they should replace it for free. You can read SB202 here.]
In the Official Aston Martin Workshop Manual there is a section on Seat Module Calibration (you can read it in full here) they actually note that:
“There is no physical indication that the seat is in calibration mode, the seat could be left in this mode for some time before a user notices.
There is nothing wrong with the seat being in calibration mode for extended periods of time, it will only be apparent to the user when a rearward / downward seat movement is required.”
Basically them saying that if you never adjust your seat it will just wait in calibration mode indefinitely until you notice.
Seat Calibration Procedure
Calibration is easy. The hardest part for me was the fear of not knowing if it would work. I wrote this article so you can get past this fear and tackle it yourself without shelling out $$$ at a dealership.
The procedure was spelled out clearly on page four of Aston Martin Service Bulletin SB141 and also in the Official Aston Martin Workshop Manual in Seating maintenance. Follow the steps in this specific order (else it won’t work).
- If calibrating the Drivers seat, move your adjustable steering wheel all the way in and down to get it out of the way of the seat.
- Power the seat all the way forward until the seat stops, then hold for 1-2 seconds
- Power the front of the seat up to its maximum height, then hold for 1-2 seconds
- Power the rear of the seat up to its maximum height, then hold for 1-2 seconds
- Power the seat back incline all the way forward as far as possible (it will likely touch the steering wheel), then hold for 1-2 seconds. This step wasn’t in the manuals, but I did it for good measure.
That’s it, the seat module should now be calibrated and you should be able to move your seat adjustments in all directions again now. Readjust your seat to a comfortable position, and don’t forget to readjust your steering column too.
Check if the other seat also needs calibrated (it probably will). Just repeat the same procedure. There is no preference in order, you can do either seat first.
Check out my video and see the actual process in action.
Aston 1936 
Hi
I wonder if you can possibly help me. I’ve just bought an 04 db9 here in England and I’ve noticed the drivers heated seat function does not work. I’ve checked the fuses and they are fine. Do you have any suggestions? Thanks from across the pond!
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Hi Luke,
Sorry I don’t have much for you help wise. I’ve not had to fettle my drivers seat heat. I suppose the obvious is to move your seat all the way ‘up’ and then stick your head under and review all the wiring connections to make sure they are all tight. Check the fuses of course. Then the dreaded dealer….
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Hi Steve
I had the same problem last night – the chair tilt wouldn’t work and the seat was pitched uncomfortably forward, making it hard to drive. I was really worried because I am away for the long July 4th weekend and every car place is closed. I googled and found your post and followed your instructions and it worked!!!! I can’t thank you enough! You saved my weekend!
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That’s terrific Jill, glad this helped out. Hope you had a great 4th weekend out in it.
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A great video and very helpful.I was tearing my hair out,the seat would only tilt forward nothing else so I kept trying every switch and inevitably ended up inclining the seat further forward every time.I asked various people for a solution,checked all the fuses and wiring all to no avail.This fix has probably saved me a fortune.If you come to the UK on holiday I will buy you a large drink!
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Hi Cornelis! Very glad this helped you out. Next time I cross the pond I’ll be happy to tip one back with you :>)
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Steve, My seats (DB9 – 2011) will move any direction EXCEPT forward and back – tried your calibration method. Because my car seats do NOT move forward or backward do I skip that step and simply do the up and down? Any other suggestions would be appreciated.
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Hi Frank. Sorry to hear about your issue. Is it possible its _already_ all the way forward? If so, just complete the rest of the process. If its not all the way forward and won’t move, its possible then the motor, switch, or seat control module are buggered up (and likely time for a dealer visit). I suppose I would suggest you check the electrical connections under the seat (visible from the front (just barely) to be sure nothing got inadvertently knocked loose. Good luck!
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Hello Steve,
Can’t thank you enough for your VERY through and professional explanation… You should be working for the AM Company!
Cheers.
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Thanks Sergio, I appreciate the feedback, keeps me going!
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Great solution. Thank you, thank you thank you. You saved me both time and money. Great and helpful blog.
Cheers,
Steve
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Great to hear!
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Hello Steve!
Great instructions!
I purchased a DB9 Volants last year and my passenger seat moves forward when I push backwards and vise versa – any idea?
thanks
Detlev
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Hi Detlev. That’s a strange one, but my instinct says that its just got the wires on backward at the switch itself or seat motor end. I don’t think there is any possible way for the control modules themselves to generate this behavior since it works otherwise. Was the seat ever removed from the car by the previous owner?
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Hi Steve,
I have 2009 DB9, my driver side seat is stuck and calibration did not work. I was told by dealer that module needs to be replaced and both has to be replaced as updated version are not compatible, for $ 1600.
I can find modules for 250 each and install them but is it true the they will need to be programmed by dealer to work with my car?
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Hello Steve .
Similar issue:- 2005 DB9 Volante, tracker fob slipped down the central side of the passenger seat. Moved the seat full up and forward and the backrest full forward. With a torch and some groping around under the rear of the seat I managed to retrieve the fob. Unfortunately now, the backrest switch would not activate any movement at all, rendering the seat completely unusable, stuck with the backrest fully folded forward. However the seat itself was fully functional. My under seat foraging must have caused the issue. After reading your page I guessed it might need to be re-calibrated, After a few attempts using the four step procedure prescribed (above) and at 6speedonline it solved the problem. The two procedures described are virtually identical but It was the four seconds, and the fourth step that did it for me. Thanks to all the previous posts for their contributions.
https://www.6speedonline.com/forums/aston-martin/274845-seats-adjustment-stopped-working-4.html#post4810410
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Hi Walsh. Glad it helped sort it out. There is sooo little space if you drop something. Slim fingers needed!
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Hello Steve
Similar issue:- 2005 DB9 Volante, tracker fob slipped down the central side of the passenger seat. Moved the seat full up and forward and the backrest full forward. With a torch and some groping around under the rear of the seat I managed to retrieve the fob. Unfortunately now the backrest switch would not activate any movement at all, rendering the seat completely unusable, stuck with the backrest fully folded forward. However the seat itself was fully functional. My under seat foraging must have caused the issue. After reading your page I guessed it might need to be re-calibrated.
You have great information and a link to 6speedonline. After a few attempts using the four step procedure prescribed above and at 6speedonline it solved the problem. The two procedures described are virtually identical but It was the four seconds, and the fourth step that did it for me. Thanks to all the previous posts for their contributions.
https://www.6speedonline.com/forums/aston-martin/274845-seats-adjustment-stopped-working-4.html#post4810410
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Thank you Steve! Without this advice, I’d be scrunched to my steering wheel for months before caving in a driving to a dealer about this. Without your posts, my DB9 would be a bit less fun to own. :0)
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Hi Ed. Glad the article helped you out. Now you can stretch out again!
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Hello Steve,
What would we do without you and your sage and timely advice….
I had sent a message to you yesterday regarding the reluctance of the passenger seat in my DB9 to cooperate with my advice to relax and return to an active operating status!! 8^)
In the promptness of time you responded to my queries and laid my concerns to rest – the concerns that this inconvenience for my wife’s comfort, (knees in the glove box) would delete my bank account severely.
Sure enough, you guided me and I’m sure others as to the simplest of the four step solution.
I was in and out of the garage within five minutes with the only the barest exertion of my right digitus secundus….
My wife exclaimed – “are you back already – I was going to have a nap!”
Thank you Steve.
BTW – one other question – any advice on how to clean the engine – mine is getting a bit ‘grotty’.
Best regards from your Canadian neighbour….
Caryl
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Steve. This sorted my seat. Many thanks!
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Hi – I enjoy following you on YouTube and through your trials and tribulations of owning a DB9. While out in my 09 DB9 Coupe, my wife pointed out the other day that the up / down button on her seat was not working; while it was operable for adjusting the seat forward and backwards. All other functions on the seat adjustment are working perfectly (forward / back / seat back forward and back). Although I tried the seat calibration procedure, it would not work because the button to adjust the up / down (Steps 2/3) would not move either up or down. Drivers seat is fully functional. Any suggestions?
Keep up the great work.
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Interesting, but that sounds like either an actual switch/motor issue for the up/down – or its possible the seat module needs reset. The actual switch does nothing but signal the seat module controller, and it then tells the motor to run up or down. If the controller is confused a bit it could create the condition. How to reset the seat module. Well, the brute force way is to disconnect the battery, but that resets everything and includes some stuff you’d rather not reset (misfires, etc). I think there is a fuse you can pull to do a more surgical strike on this.
If you check out this article of mine on the fuse box, looks like it will be Fuse 84 or 85 depending on the side.
Let me know how it turns out.
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Good advice. Do you know if you can replace the position switches without memory for ones with memory buttons and they will just work using the same seat modules? Thanks.
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Thank you, thank you, thank you STEVE !
I had the same problem with my 2007 Vantage (5,574 miles)
after changing out the battery.
I worked like a charm !!!
Your instructions are perfect !
Thanks again.
Ken Williams
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