Hello,

Newb post here. I've been searching these forums for the past two days and still can't find a solution. I've got a 2003 Audi A4 Avant 3.0L. After driving the car around all day, my wife made a stop and was unable to start the car again. The car will crank so the battery and starter appear good, but it does not turn over. I initially thought it was the fuel pump so I got a new one of those and replaced. Same issue, won't start. I measured the voltage at the fuel pump and it's only getting .8 V when the key is turned. This does increase from about .02 when the key is off so I'm not sure if it's a relay issue or not. Also, not sure if this is related or not but if I try and read any codes from the car, the reader says "no link". Reader is good as it works on my other car.

At this point I'm out of ideas. Someone mentioned maybe the ignition switch in another tread but this doesn't seem likely. Could there be an issue with the ECU and is there anyway to test? Also, I can't find the fuel pump relay on the car so does anyone know where it is and how to access it? Any other ideas out there? Thanks for your help.

 

Ok, if your ignition key is turned but you don't hear a click from the starter at all, there's a relay that controls that, is relay 215 or something like that, is really difficult to get to and you access it from the kickpanel under the steering wheel. I think Audizine has a few pictures of it but I don't remember where, just stroll over there and do a search for relays, I'm sure you'll find it.

When you changed your battery I can almost bet that you had water in there, that's the most common cause for that relay to fail.

 

Could be the relay, but i would change the fuel filter first.

 

Starter is working fine. The Car cranks but won't actually start. Are you talking about the fuel pump relay being under the steering wheel?

I should also mention that I briefly jumped a wire with 12V across the fuse for the fuel pump . I could hear the fuel pump running and had pressure where I disconnected at the rail but the car still didn't start so I don't think it's the filter.

Does anyone know what the voltage to the fuel pump should be? If it is too low, what would cause this?

 

I'll starting to lean toward the ECU being bad. When I turn the key the Check Engine light does not come on at all. Is this normal? Also as a mentioned earlier, when I connect my code reader, it says no link. Do these go out often? Is there any other indicators that would point to a bad ECM.

 

to make sure you're getting fuel you need to disconnect the fuel rail, where the hose comes into it, and put the hose into an empty bottle, then open the key and see if fuel comes out of the hose, if it does the pump is ok, if it doesn't the you need a new pump.

 

I tested the fuel pump again by hot wiring across fuses and fuel is getting to the rail. Also replaced the fuel pump relay and the car is still not starting. My neighbor brought over his reader from his shop and when we plugged it in, it is not able to communicate with the PCM/ECM. We ended up removing the ECM and he is going to bring into his shop to check all the solder joints. Is there any other things that could cause the car not to start? If it's not the ecm, I'm not sure what we'll look at next.

 

I tested the fuel pump again by hot wiring across fuses and fuel is getting to the rail. Also replaced the fuel pump relay and the car is still not starting. My neighbor brought over his reader from his shop and when we plugged it in, it is not able to communicate with the PCM/ECM. We ended up removing the ECM and he is going to bring into his shop to check all the solder joints. Is there any other things that could cause the car not to start? If it's not the ecm, I'm not sure what we'll look at next.

 

The only other thing I can think of is that the car can be drowned, but is unlikely. Check your coilpack harness to make sure is grounded properly.

 

Got my Vag-Com on Friday. Here are some of the readouts which were similar for most of the different control units:

01810 - Actuating Motor for Temperature Flap; Right (V159)
41-10 - Blocked or No Voltage - Intermittent
00604 - Potentiometer Positioning Motor for Air Flow Flap (G113)
30-10 - Open or Short to Plus - Intermittent
00532 - Supply Voltage B+
53-10 - Supply Voltage Too Low - Intermittent
01317 - Control Module in Instrument Cluster (J285)
49-10 - No Communications - Intermittent
00474 - Control Module for Immobilizer
49-10 - No Communications - Intermittent
00474 - Control Module for Immobilizer
27-10 - Implausible Signal - Intermittent

So it looks like it's probably an issue with the ECM. Is there anything I should look into as to what originally caused this before I try and go find a new ECM? Don't want to get a new one and have the same problems.