DB9 not starting…. But ok now

[Stonic]

Drove the car for 40 miles last night. Parked overnight and this morning when I went to start it the starter button did nothings. Various warning (emissions check, Cannot display gear… ). Have not had any previous indication the battery is going so put the lights on – worked fine, pressed horn, worked fine etc. I decided to disconnect battery earth, left it for 5 mins and then reconnect.
All working fine now!

Just a bit worried in case it happens again. In 18 months of ownership I have had nothing like this at all. It’s a 2008 on original battery so wondering if maybe the battery is on the way out or it was just a random electrical gremlin….

[krisdelta]

The battery is possibly on its way out, a dodgy one can cause all the weird symptoms you describe. If it's not giving you any more bother, just get it checked at service time.

[ds2000]

If you have access to a multimeter get it across the battery terminals. Do it with the car off, you should be around the 12v mark, start the car and check again, with the alternator running it should be nearer to the 14v mark, if the latter is true then you have a dying battery.

• Figures are off average cars over the years, not Aston specific.

[MrCrazy]

Stonic said:

Drove the car for 40 miles last night. Parked overnight and this morning when I went to start it the starter button did nothings. Various warning (emissions check, Cannot display gear… ). Have not had any previous indication the battery is going so put the lights on – worked fine, pressed horn, worked fine etc. I decided to disconnect battery earth, left it for 5 mins and then reconnect.
All working fine now!

Just a bit worried in case it happens again. In 18 months of ownership I have had nothing like this at all. It’s a 2008 on original battery so wondering if maybe the battery is on the way out or it was just a random electrical gremlin….

I had this exact same problem on my DB9. The Aston AA guy came out and he said it needed a computer reset. This was because the battery was in a low state of charge due to lack of use. From that day on I always left on charge when not using.

This however didnt cure the problem as it came back again. The cat wouldnt start and then for some reason it would reset and start!

Stratstone eventually found the problem and it was down to a £1.50 gearbox relay believe it or not.

Dont know how far you are away but they may be the best ones to sort, or at least tell a garage that you want a new relay fitted. I was told it was accessed from the boot and is a simple unplug and plug back in.

Never had the fault again but having said that I did swap the car about 6 months later.

Hope this helps?

[Stonic]

Thanks for the replies. Any idea if I could check the voltage as accurately using the positive terminal in the engine bay and earth to alternator mount? Would be quicker than undoing all the bolts to get the the battery positive terminal...

The point about the gearbox relay is interesting. I was 99% certain it wasn't a flat battery as I use the car a lot and have never had a "slow" starter which you might expect of a dying battery. Any idea which relay it is? The Owners Manual seems pretty useless on this front. Would be cheap preventative maintenance.

Thanks again.

[MrCrazy]

Stonic said:

The point about the gearbox relay is interesting. I was 99% certain it wasn't a flat battery as I use the car a lot and have never had a "slow" starter which you might expect of a dying battery. Any idea which relay it is? The Owners Manual seems pretty useless on this front. Would be cheap preventative maintenance.

Thanks again.

Sorry, not too technical so can't help there. I recall warnings also saying something like gear selection not possible as well as reduced engine power?

Stratstones Wilmslow sorted for me.

[MrCrazy]

Stonic said:

The point about the gearbox relay is interesting. I was 99% certain it wasn't a flat battery as I use the car a lot and have never had a "slow" starter which you might expect of a dying battery. Any idea which relay it is? The Owners Manual seems pretty useless on this front. Would be cheap preventative maintenance.

Thanks again.

Sorry, not too technical so can't help there. I recall warnings also saying something like gear selection not possible as well as reduced engine power?

Stratstones Wilmslow sorted for me.

[Sump]

MrCrazy said:

Stonic said:

The point about the gearbox relay is interesting. I was 99% certain it wasn't a flat battery as I use the car a lot and have never had a "slow" starter which you might expect of a dying battery. Any idea which relay it is? The Owners Manual seems pretty useless on this front. Would be cheap preventative maintenance.

Thanks again.

Sorry, not too technical so can't help there. I recall warnings also saying something like gear selection not possible as well as reduced engine power?

Stratstones Wilmslow sorted for me.

I have the same issue as you.

I've looked into it and it looks like they replace the TCM relay which is the mechatronic relay for the DB9.

It's located in the rear fusebox on the left under R4.

Edit - it's actually a 4 pin relay

Edited by Sump on Wednesday 1st April 10:48

[Jockman]

Sweet Jesus, Sump, this thread is over 2 years old !!!

Might as well start a new one

[Sump]

It's cached into google for DB9 not starting so best to keep everything related all in one thread, especially with my having the exact same issue as the OP Thought it'd be wise for future searchers!

[mrpseudonym]

Sump said:

Thought it'd be wise for future searchers!

This kind of information is gold. 10 points for the follow up Sump

[Sump]

No problem.

And it's completely fixed my issue, I'm happy

I was able to trigger the issue by driving in manual mode with the paddleshifts, then turn off the car without pressing P, leaving it overnight and then the next morning when starting up on the instrument cluster it wouldn't say P it'd just have a dash and all those gearbox errors and engine errors. I'd have to switch it on and off around 4-5 times until the instrument cluster would say P and then it'd start.

Today it started without a hitch!

[JoeGS]

Hi all I have not submitted before but I thought this post may be useful. My DB9 failed to start while visiting Newport Pagnell Works - handy! When the key was turned, all usual lights came on but nothing happened when starter button pressed. A technician came out armed with a powerful battery charger assuming it was a flat battery but this did not help. Next, went to the starter and checked the 25 amp fuse in the engine compartment - this had blown. Changed the fuse but blew again so fitted a 30 amp just to get us mobile and back to the hotel. The following day I replaced the fuse with a 25 amp and the car started. It has been fine since. I can only think that the starter was stuck or it was a solenoid problem? Anyway OK since. As it takes a couple of minutes to check, it's worth doing first.

[M4rsb4rs]

Dear Aston Martin DB9-ers,

I am having some issues with starting 2006 db9 recently. Battery charged, running 12.7v, dash lights up and all seems good but pressing the start just gives a 'click'. Try a few times and the click stops as fuse (25 starter fuse) blows. Weird thing is this is intermittent. Put a jump pack on (I only have a 1100amp, 500 crank pack) and it starts no problem. The local garage say starter motor but some days get in and it starts on the button no struggling.

If anyone has any idea what could be causing this issue it would be good to hear some theories to try out. Thanks in advance, Andy

[leman600]

Battery running should be 14plus volts if alternator is working well. Need to look at this. Voltage could be falling through the floor when demand made.
I had this fuse go once and not sure if this was cured when I found the starter solenoid primary wire was less than tight with a broken spring washer. Got to this from below with my V12 Vantage. Access a bit tight but not too bad.

[M4rsb4rs]

Thanks for this reply. I have not had the courage to jack it up on the drive and remove the skid panel and investigate this yet. I have heard that the starter is hidden by the exhaust and cat on the db9 and this sounds like too much for me to do with the weather closing in

As the issue is intermittent even when stood I was hoping to rule out the possibility of it being the starter motor connection. I was tempted to change the relays out as a test first, not sure if it will be worth doing?!