DB9 limp mode-dealer can't figure out
 

Hi All,

I have 2009 DB9 Volante with 52K mile
I ma having issues:
1) car goes in "limp mode" randomly, I had sent it to dealer, who drove for like 20-30 miles and could not replicate the problem, car comes back in I drive 5.7 miles and limp mode is back
2) if I turn off the car and restart it limp mode goes away
3) error code stores are P1712: dealer verified that software in ECM and TCM was correct.
4) Now it also shows P0087 Fuel rail/system low pressure: dealer tested pressure at fuel line and it was fine. But i suspect that issue happens intermittently so may be fuel pressure is dropping intermittently ? weak fuel pump, bad fuel module?
5) Last time about 2 years and 20K miles ago, I had replaced ignition coils (during which i had removed fuel lines, fuel injectors, fuel rails), I think after that i had noticed that if I want to start the car I had to almost prime the car i.e. I insert the key but dont start th car, then remove the key and then reinsert the car, if I follow this ritual it will start in a short normal crank. If i dont do that there will be a long crank and it may on may not start. I wonder I goofed up something at that time and it has gotte worse with time?
6) when i drive the car and press gas paddle, I hear a whistle like sound, but some time it happens when i apply brakes too and its not brake pad squeal. hopefully my video will upload so you canker that sound. I wonder it its connected to above issue or its separate issue.

Dealer kept my car for about 1.5 weeks, BTW AM orlando now does not even provide loaner cars, they said their policy is to discourage loaner cars and if they give it, they will only give it to only people who have bought the cars form them, which sounds ridiculous, as BMW, Kia, Honda, Toyota alll provide loaner cars. And after all they were never giving AM as loaners, they had cheap american brands before.

I suggest to check your battery. You can swap it with other car to see if the problem is cured. I had similar case, where a 2 year battery tested ok did similar symptoms.

Thank you, I was going to mention that but forgot.
yes I replaced the battery already with a brand new one. Did not help.

here is the link to video of noise, which i cnat load it here so just loaded on youtube.

May sound odd but I was having limping problems coming out of a stop light at times and realized that my brake switch was sticking... tricking the car as I pressed the gas and the brake lights were still “on”... brought a new switch from scuderia and the limp went away....

a big difference with a new switch... the plunger spring wears faster than the driver can recognize. if that switch is slow to retract in when you release your foot off the brake... it will affect how 1st gear responds... One of the pins inside the brake switch feeds the ECU and if the plunger is “sticking” even for milliseconds it delays the signal to the ECU thus limping until “brake light” is off and then the car lunges forward...

did you ever solve this issue? I have the p0087 code now and my car is randomly going to limp mode. I have checked a few things but if you ever found a cure that would help tremendously.

I sent to another dealer and he told me I need new fuel pumps, I plan to replace them my self but with covid 19 it has gone on back burner

I understand! Did he say which side fuel pump it is or just to replace both? Also what year and mileage, just curious.

Both plus both fuel filters
2009 DB9 Volante with 62k miles

where are you buying your parts? I'm Planning on doing my own work also mine is a 2009 DB9 coupe 57k miles. I have already pulled some of the interior and found the access and the driver modules, looks like a pain! But hopefully something I can handle!

Probably Scuderia
mine is Volante so access is easy
I heard for coupe you have to drop the gas tank

oli plan to take the fuel pump out and see if real brain of the fuel pump is actually ford part ?
AM sells fuel pump with housing but real brain or working part might be a ford part

My jags used ford pumps. The gyrator pumps themselves are available as separate items online as are the filters. Having had the top of my tank off I don't think this will be "easy in a volante because each pump is offset from the access hole. The plastic pump assembly clicks in place with a mount assembly at the bottom of the tank. Getting it clicks in place requires good hands. To do this on my m5 required me to go to a salvage yard and look at a tank in a more leisurely fashion.

YMMV
Larry

https://cimg2.ibsrv.net/gimg/www.6sp...9775067018.jpg
Finally I removed both fuel filters and fuel pumps today.

I tested both of the fuel pumps by connecting them to 12 V battery directly and they seem to work well.
Filter was regurgitating brownish looking fuel when tilted.

Fuel pumps are basically VDO (I think its a german manufacturer) I found it at various us sellers.
https://www.fcpeuro.com/products/lan...pump-wgs500012

Land Rover Electric Fuel Pump - VDO WGS500012

Fuel filter are also VDO

Land Rover Fuel Filter - VDO WFL500010

https://www.fcpeuro.com/products/lan...lter-wfl500010


advantage of FCP euro is that the parts comes with life time warranty

for the fuel pump assembly on one website I was even able to see "257" written on the pump like original one.

In my case when i was taking driver side pump out electrical connectors came off very easily without even trying so i suspect the connector was loose thats why i was having intermittent limp mode. Once my filters comes i will reinstall and report back. For now i ma not replacing fuel pump assembly, will just replace the filters.

Removing the pump was actually easy, I took off tonneau cover (the metal part which cover the fuel tank area , and moves up and down when raising or lowering the convertible top).

https://cimg1.ibsrv.net/gimg/www.6sp...97583d3c95.jpg

https://cimg3.ibsrv.net/gimg/www.6sp...16b69efb71.jpg

https://cimg0.ibsrv.net/gimg/www.6sp...b884b46083.jpg
Last picture shows what came out of the car (2009 DB9 Volante) and whats available from VDO. If we can figure out what pump are they using )the metal part) then we can just replace that and that is about $ 100 each, I don’t see a reason why whole assembly should be replaced.