A3 2.0 TDI 140 DTC P3103 V157 - Motor Intake Manifold Flap now wont start at all

gunnag

Registered User
I have a 2007 Audi A3 Sportsback with the 2.0 140ps 16v tdi engine & DSG box. I have owned the car for four years and it has run flawlessly. The car has 115k miles and has been regularly serviced, initially by Audi and latterly by myself, the cambelt was changed at 70k by Audi and other servicing has included oil and filter changes (using vw507 oil) every 7k or so, DSG oil change at 80k, air filter change every 20k, a new ABS/ESP modulator pump at 110k and a new battery 2 months ago.

Earlier this week, the EML light appeared and after scanning with VCDS I found a couple of DTC;s related to the throttle body P3103 & P0691, additionally one of the fuses next to the battery was blown apparently confirming a faulty throttle body. Despite these faults the car drove fine although the aircon would sometimes switch into econ mode.

Today I started the car and it ran OK before cutting out completely after 1/2 a mile. In addition to the previous DTC's, IM now getting P3338 - Activation Glow Plug Control Module, P1501 - fuel pump relay short to ground, P3004 - Relay for Low-Output Preheating of Coolant & P3006 Relay for High-Output Preheating of Coolant.

I tried several restarts with no success and called a rescue company. They checked the diesel supply and confirmed nothing was being pumped to the engine, however the fuel pump fuse was OK. I ended up being towed home.

So my question is whats going on? Is the throttle body fault related to the new DTC's or is it a fluke? One issue is that it was absolutely chucking it down when the engine stopped, maybe water leaking into the ecu? I'm tempted to initially try swapping the fuel pump relay and see if this helps. If not the next step will be the fuel pump itself and I'm led to believe the solenoid pump can be swapped relatively cheaply without changing the complete pump and sender unit.

I guess I will need to change the throttle body as well so any suggestions as to a good recon or new source would be good.

All info welcome.
 
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hollows wife

Registered User
remove the pipe to the throttle body ,turn ignition on feel to see if flap is stuck shut ,if so this is why it wont start no air is getting to the engine . gsf do them so do euro parts around the £150 mark
 

gunnag

Registered User
Agreed, there may be no air getting to the engine because the throttle body is shut, but would that explain why there is no diesel fuel being pumped and the other DTC codes?
 

hollows wife

Registered User
when the throttle flap jams it blows a maxi fuse under the bonnet and it definately causes an error with the aircon as it uses the same supply feed .
fuel pump relay can be bridged over just to see if it primes the car with fuel, if not it could be crank sensor related as well .
definately all related i doubt the ecu is drowned with water as its well hidden under the scuttle panel but every problem is different on every car .

i would check the throttle flap and check the maxi fuses under the bonnet first .
 

Boon

Registered User
Diesels don't have throttle bodies, we had this discussion other week! Lol!

The Manifold Flap is open all the time the engine is running, closed only at shutdown to 'help' with shuddering also as an emergency stop in the event of a 'run a way'

As said above its likely this is closed and not letting in air, it will need to be replaced first then move on to other faults if they are still present
 

hollows wife

Registered User
Diesels don't have throttle bodies, we had this discussion other week! Lol!

The Manifold Flap is open all the time the engine is running, closed only at shutdown to 'help' with shuddering also as an emergency stop in the event of a 'run a way'

As said above its likely this is closed and not letting in air, it will need to be replaced first then move on to other faults if they are still present

ok ok anti shudder valve /shut off lol its just easier for people to understand the concept of throttle body

but i would myself whilst waiting check the anti shudder/manifold flap , if its stuck shut i would then unplug it before i check the maxi fuses ,replace the blown one read and clear the dtc's then replace the fuse and see if it blows again instantly ,if it does then the main fault would probably lie in the manifold flap been fubared
 

gunnag

Registered User
Thanks for the replies, I have just checked and the Anti Shudder valve is definitely open. I disconnected the plug to it and swapped the 10a fuse next to the battery for a new one. Tried restarting with no success, however the fuse was not blown this time so I guess the fault must be elsewhere. Will scan the car tomorrow and see if any new codes appear.

Does anyone know where the fuel pump relay is located, is it the relay marked 100 in the battery fuse box? I checked this relay by powering the two small terminals and this resulted in continuity between the two larger terminals, so this relay seems to work OK.
 

hollows wife

Registered User
sure its relay 109 . or 449 if memory serves me correctly its not the 10 amp fuse its more like a 40+ amp maxi fuse the blows (the very large ones)
 
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gunnag

Registered User
Thanks, but where is it located? I can only see one relay in the battery fuse box (the one marked 100).
 

gunnag

Registered User
I have taken a photo of the relays located under the dashboard see below, I can see relays numbered 373, 370, 53, 460, 395, 449 but have no idea which is which, anyone know which one is the fuel pump relay?

a3-relay.jpg

I also tested the voltage on the fuel pump fuse and found 12.5v with the ignition off and on. I suppose this confirms the power to the relay is OK?

All info welcome.
 

Nessy

VW + Audi mad
Holy thread resurrection I know, but I had the dreaded engine management light appear on Sunday night and the fault codes when read were P3103 and P0691 too.
A Pierburg throttle body/ASV (or whatever you want to call it!) was duly fitted fitted today and the fault codes cleared but the engine management light wouldn’t go out
After a lot of head scratching and internet reading I discovered that F8 might well be the fuse that controls the radiator fan circuit 1 on earlier models but on my 2007 it is F24, which sure enough when checked was found to have blown.
One replacement 10A fuse in that location and the EML light has now gone out.
 
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