Aston Martin 3 way switchable Exhaust Valve, most modern Aston Martins have a valve in the exhaust, this automatically switches between valves open (loud) mode and valves closed (quiet) mode depending upon RPM. Most people know of the infamous fuse 22 (15 on later cars) which changes the exhaust to loud permanently, (removing fuse 22 from the Fusebox in the boot (trunk) removes power from the solenoid controlling the valve, causing the valve to stay open and thus loud all the time.)
AS can be seen above, the valve is vacuum operated. The system consists of a vacuum pump and a reservoir, the vacuum pump runs when the ignition is on, switching off when enough vacuum is formed in the reservoir. The solenoid controlled by the ECU and Fuse 22 allows vacuum through to force the valve, above, to open.
When I bought my DB9 it had a 2 way switch to switch between normal automatic mode (loud at idle and above 4000 rpm) and loud all the time. This switch had 2 cables that ran to the rear fuse box and replaced Fuse 22.
As can be seen in the wiring diagram above, the solenoid has power supplied by Fuse 22, thus removing the fuse or cutting the power will cause the valve to open permanently, however on the earth side we have more possibilities; as stock its controlled by the ECU and the ECU will connect to earth at the correct rpms, cutting the wire is the same as removing the fuse, permanently loud, and connecting directly to earth will be permanently quiet mode.
A SPDT (single pole, double throw) wil allow us to choose from any of the above functions at will, and a DPDT switch will also allow us to have an Indicator that shows what mode we are in ( to be added)
We connect the centre connector to the wire that was connected to to Connect C2243, one side to the connector and the other side to earth.
The black connector to the left of the green connector is C2243 in the footwell on the right side of the car.
The wire that we need to intercept is the White wire in pin 19, 4 from right on the bottom row, cut the white wire, the connector side to one side of the switch, the other part of the wire to the centre terminal of the switch and the remaining terminal on the switch to earth
Decat
Amongst other modifications my exhaust has already had the secondary cats deleted, the DB9 has 6 Cats, 4 primary cats in the manifold and 2 secondary Cats under the car, the primary cats alone are enough to pass emissions test is most parts of the world. Removing the secondary Cats improves the sound and adds a bit of power to the DB9, see here for more info
X – Pipe
I also installed an X- pipe to change the sounder, smoother and more exotic sounding.
Which wire is it that needs to be spliced for cars where the exhaust valve is linked to Fuse 15, instead of Fuse 22?
How do you know which connector is C2243?
Is there a list of these somewhere?
If I remember correctly all the connectors in that area have a different number of pins, C2243 has 22 pins.
I’m replying to an old post but maybe someone will read this. I just went to the DTC here in Switzerland, the noise police.
I was looking for a certification of good behavior! In order to register an American spec car in Switzerland, you must pass this test. At $1 000.- the visit, it is specifically bitter to fail it… which I did…
On idle it should make no more than 74 decibels. My car was at 81… at 4500 rpm the max should be 84 decibels, my car was at 94…
The technician did say my exhaust valves were open the whole time.
First, how do I fix this issue, and it’s not fuse 22 related. Maybe the relay?
Second does anyone have the manufacturer’s decibel chart to see if this American spec car would pass this test if the valves were closed.
Now van it be programmed somehow to meet those noise guidelines?
Thanks for your input,
Francis
Hi,
You don’t mention what year or model your car is.
However DB9s and Vantages have their valves set the same, the Valves are open at idle and up to 1500 rpm then close and open again at 3500 rpm so if your test is at idle and 4500 rpm it would fail whether the valves are working properly or not.
If fuse 22 has been removed for sometime, ensuring the valves stay open they can seize, so may need freeing off with penetrating oil and some persuasion.
You would then need to follow the instructions in this post to enable the valves to be kept shut during the test.
Hope that helps
Paul
Oups! My car is an Aston Martin DB9 Volante from 2009 with 16 000 miles on it. Sorry that I missed that info!
Francis
The issue with the DTC testing center is that the valves must be working on their own free of any driver’s ” switch” intervention.
I did ask about that and to the Swiss this would not only fail the car but “tampering” with the OEM settings would result in an hefty fine. They don’t joke with that over here!
So is there a way to reprogram something to get it to only open at 4600 rpm, for exemple?
A German technician at Aston Martin Safenwil, the importer for Switzerland told me, if I understood him correctly ( my German is so, so) that there is a $ 4 000.- tweak they can do on the CPU of the car to make is Swiss legal.
Is that so or just a ” park your car here and come back at the end of the day” deal? Or fo they really do something to the car?
Mind you, for that 4 000 Swiss Frank deal, they generate the import document for my specific car and no further DTC visit is required. 4 000 chf there and no need for the 1 000 chf at DTC…
Francis
My understanding is (and I have done exactly the same thing myself on motorbikes) is that a remap can achieve this, which would be cheaper than what you have been quoted, not sure if they can fix the idle speed valve opening as well.
The important reading is the 4500 rpm decibel level. With a reading of under 80 at idle speed ie with the closed valve and a reading of 88 decibels at 4500, which is the limit, the car will pass.
How can I do a remap ?
Or who could do it for me if I send the module out?
Francis
A few places in the UK, BF, DAE
Probably worth checking if you have a secondary cat delete first as that makes the car much louder.
Paul,
Just checked and my secondary cats are present. I think I will print the diagram 68 from the workshop manual and take it to a buddy of mine who knows how to follow those diagram and use your advice to get my valves to stay closed at first. If we achieve this, my next investigation will be to get those closed valves to open at 4 600 rpm.
Thanks for your guidance and input. I will keep you posted on my trials!
Francis
Hello Paul,
I would like to thank you for your website. Your comments have been super usefull to solve my noise issue.
I created a replacement connector to test the valve opening and closing. By routing the white cable on the test connector of the pump to open/ close the exhaust valve, I connected it to a bolt on the swaybar clamp, (it was very close!) and used the other yellow cable to connect to the yellow side of the original plug. It worked! Upon contact, the valve closes and stays closed. The original connection would close the valve upon engine start and reopen within a few seconds.
Thank you again!
One last thing. I want to keep the exhaust valve connector unmolested in order to pass the noise test without raising any questions from the examiner. So I guess I could intervene somewhere farther on the white cable. In your exposé about installing a switch (I won’t do that has it is forbidden to manually control that valve, in Switzerland) could I cut it in the passenger’s foot well on a lefthand car, and connect it to ground there?
Thanks for this last input request!
Francis
Paul,
Job done! I connected the white cable from the passenger’s foot well to a ground and it works perfectly. My, non professional decibels readings done with a £20 Chinese db reader before at idle, 19 1/2 ” away from the tip of the exhaust and at a 45° angle was 80 decibels before bypass and 74 decibels after. Right at the limit. The 4500 rpm test was a bit off as you need to take the reading at exactly 7 meters away as the car rolls by at 4500 rpm. Max here was no more than 88 decibels. My readings 6″ away from the exhaust tip was 82 before bypass and 89 after bypass. This second test was off and non conclusive. I will take it again under better circumstances. But my thinking, unless the reading unit is just crap, if you take 89 decibels at 6″ move that back to 7 meters and add the rollings noises, it should be good to pass the DTC test.
So once again, thanks for everything you gave me with your website and comments!
Francis de Leeuw
Hi Francis,
Sorry for the late reply, happy you have resolved your problem.
Only one thing to be aware of is that power will be restricted at the top end by the more restrictive exhaust and some people say its not good for the engine to have the valves closed all the time but I’m not sure how true that is.
Regards
Paul