Hi,


I need help locating the fuel pump in my car. It is an 04 Audi A6 3.0 FWD and I thought it is under the rear seat but when I removed the seats it is not there. Could it be in the tank for this model and year?

Also, need help locating the fuel system test port. I found the fuel pressure regulator but no luck finding the test port.

Any pictures with illustrations will be greatly appreciated.

 

I believe I found the fuel pump located in the trunk and it looks like it is a combined unit with fuel level sensor. Anyways, I checked voltage at the connection (has four wires, 2 thick wires and 2 thin wires) voltage at the two thick wires are only showing 3.50 Volts. I took the black relay off (relay number 219) from the ECU box and still giving me 3.50 Volts but the fuel level is not working on the gauge since I took the relay off. I also disconnected the fuel filter and no fuel coming out with the key in ON position. I hope it is just the relay.

How much voltage should be coming to the fuel pump?

 

never mind I believe I am looking at the wrong relay in the ECU box, there are more relays under the driver foot well and not sure which one is for the fuel pump. I'm only getting 3.50V at the two big wire connecting to the pump, so not sure what is the problem. Also, I jumped the pump with 12V and there was nothing happening. Now, I am clueless what to do, change the pump or the fuel pump relay which I cannot locate.

hope someone can tell me which one is the fuel pump relay....thanks.

 

The pump itself is in the tank. If you need to change it it is best to do it when the tank is near empty.

Some Audi's pressurize the fuel rail when you turn on the key then once pressurized the pump turns off until the engine is rotating. Some do not pressurize it until one of the sensors tells the ECU that the engine is rotating.

 

okay, I believe I found the relay under the driver's side wheel well, no 372, part #4D0 951 253 and the label next to it says "diesel F". I checked the voltage at the relay connection and shows about 11.5V so tested the relay with 12V and I do not hear any clicks.

Also, tested the fuse with the battery ON and only getting 3.50V similar what is by the pump harness. So, I'm assuming bad relay but not sure why the pump wouldn't run when I connected 12V from the battery straight to pump. Could it be both the relay and pump has gone bad?

 

I had filled the tank half way couple days ago and the car stalled yesterday so now it doesn't start at all so I have to siphon the fuel out if the pump needs to be replaced.

Okay, I did a final test with the same relay plugged in and cranked the car and I'm getting 12V at the pump connection so I have come to conclusion that it is bad fuel pump.

 

I have replaced the fuel pump in older petrol Audi's both with near full and empty tanks. Since you have to reach in to remove the pump it is easier and cleaner when near empty.

 

I will siphon most of fuel out before starting on it. I have ordered the fuel pump (Bosch 69733) online and should be here by next week.

 

My tank was at half and did not leak out. Be careful with the convectors as they are brittle. Mine died at about 142,000 and 11 years. It is not a bad job, be careful and go slow

 

Thanks. I got the Bosch 69733 from autopartswarehouse.com for $145 and it came in yesterday. The fuel tank was half empty and got the old one out and swapped it with new one. I just used my hands with work gloves to undo the old pump from the tank and it came out easily. The new bosch pump installed easily as well but it was not tight / seated properly like the original audi pump. Also, noticed that the outer casing on the new pump is flimsy and not as strong the old one so I swapped it out with the old pump's outer plastic housing (top & bottom) which secures to the tank area and installed on to the new pump. It did lock in properly and tight to the tank and installed new fuel filter as well and the car is starting fine with no problems.