How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask AudiDoc Your Own Question
AudiDoc, Independent Audi Shop Owner
Category: Audi
Satisfied Customers: 1695
Experience:  I've been working on Audis since I was 18 and own an independent Audi repair and performance shop
Type Your Audi Question Here...
AudiDoc is online now
A new question is answered every 9 seconds

Audi TT Quattro 01 TT Quattro. No power getting to Fuel Pump.

Customer Question

01 TT Quattro. No power getting to Fuel Pump. Fuel pump runs fine on 12V jumper. Replaced relay, fuses metered good. Replaced fuses anyway, fump pump, ECM. ECM relay appears to not getting proper power as well. Fuses check good.
Submitted: 6 years ago.
Category: Audi
Expert:  AudiDoc replied 6 years ago.
Hello there. Is this a 180 or 225?
Customer: replied 6 years ago.
Expert:  AudiDoc replied 6 years ago.

yep, they all have 1.8 turbos, but there are two different versions, the 180hp, with a single tailpipe, and the 225 with dual exhaust

Customer: replied 6 years ago.

it is a 01 quattro, AWD, 225hp. Secondary fuel pump is working, has just shy of 1/2 tank of fuel. I have the factory manual and suspect the problem is within the emergency fuel shutdown or the ECM. There is no power getting to the fuel pump. Also appears that the ECM relay under the hood is also not getting power as the relay is not moving in response to the key, but when I moved the relay to secondary air position in bus, it moved in response to the key. Have not checked the injectors yet or done a fuel pressure check yet as the fuel pump no worky. OK lite on the trouble panel, no MIL's, but have not yet had a code dump on it. Continuity checks on the fuel pump, and the pump ran with a 12V, 15AMP jumper. When I disconnect the harness from the primary pump, I get the fuel warning lite on the trouble panel.

Expert:  AudiDoc replied 6 years ago.
Ok, let's try something first. Please put any removed components (relay, etc.) back into proper position. It might be best to have two people available here. Get to a position where you can test for power at the pump. Have all doors shut for at least 2 minutes. While you're monitoring power to the pump, have another person open the driver's door. Please let me know if the pump gets power. Also, you mention a primary and secondary pump? This car should only have one pump

Edited by AudiDoc on 1/31/2011 at 5:45 PM EST
Customer: replied 6 years ago.
All power checks have been done in the method in which you have directed in accordance witht the factory manual. Car is AWD so the fuel system is designed with a secondary pump on the right side of the tank which acts as a transfer pump to move fuel over the driveshaft galley to the left side of the tank to the primary fuel pump...I am not an Audi expert and figured that out. The front wheel drive cars have no driveshaft galley, so they have only one fuel pump. If the car will not start while reading approx 1/4 tank of fuel, then the secondary pump is not lifting fuel over to the primary...There is no power getting to the primary fuel pump, the fuel pump relay or to the ECM relay under the hood. All methods of testing the fuel pump have been completed. The pump does not power up with the driver's door, or with the ignition switch. All fuses, fusible links and relays have been tested and I replaced the fuel pump relay (with factory part) just to be sure. All relays, fuses, et al are in the proper positions, just moved them to test for movement. Battery is fully charged.
Expert:  AudiDoc replied 6 years ago.

Very thorough, thank you. Do you also have power on the 30 terminal, panel side of the relay? Also, plesae check that fuse 13 has power to it, key off. I know these seem like simplistic questions, but I just need to cover every base before getting into more complex questions. I'm sure we've all been through tech support calls related to internet outtages, where the support person asks if your modem is plugged in.


However, don't worry, we'll get to the bottom of this.

Customer: replied 6 years ago.

13 has no power

30 has 12.4, same as battery.


Expert:  AudiDoc replied 6 years ago.

Very odd that you're getting power one spot and not the other, and here's why:


Attachments are only available to registered users.

Register Here



That 30 terminal is a common supply. Either you've got a problem behind your relay panel, or.....and this wouldn't make any sense, but please check all of the fuse strips on top of the battery. 2 of them supply power to the 30 terminal


Attachments are only available to registered users.

Register Here



Now, I need you to check this thoroughly, since I've seen a lot of these fuse blocks melt internally. So, while the fuse strip still looks good, power isn't being transferred out through the large red wires. Or if it is, there's enough resistance inside the partially melted fuse block to keep "enough" amperage from going through the circuit. Since you're not seeing a voltage drop from true battery voltage to the 30 terminal. I'm curious if voltage is dropping off while the relay is trying to energize.

Customer: replied 6 years ago.
All 5 of the fusible links read identical voltage (12.4) on both sides. Meter grounded to neg on battery. All 5 tone on continuity check. However, on the Micro panel, all terminals test at battery voltage except 87F (0 volts) which appears to be the position of the fuel control relay. So, maybe I answered your earlier question improperly because I tested the terminal labelled "30" on the bottom of the micro panel instead of the lug under the fuel pump relay. Fuse position 13, brake light, tests at "0" volts, key off.
Expert:  AudiDoc replied 6 years ago.

Does your meter go to 100ths of a volt? I'm still suspecting a break or voltage drop somewhere between S132/S134 and the fuse panel. I'm using fuse 13 as a test to determine when that 30 circuit is powered at the fuse panel and relay panel. If you can set your meter to 100ths of a volt (12.xx), please attach your negative lead to the negative post of the battery, and check one of the fuse strips with positive. Take note of that number. Then move the positive meter lead to the 30 threaded stud under the dash. Let me know what both numbers are.


As I mentioned before, the fuse strips can show power on both sides of the strip, but still not have continuity through the plastic fuse panel there, and going out through the large red wires, and to the panels inside the car.

Customer: replied 6 years ago.

12.27 between battery and fusible link


12.27 between 30 threaded stud and ground


Strange to me as well. Would think there would be some voltage drop. Used both of my meters and both gave the same numbers.

Expert:  AudiDoc replied 6 years ago.
Wow. Agreed. That does seem quite odd. Ok, time to get behind that relay panel and fuse panel to find out why you don't have power to that 30 terminal. So far, everything I can think of in my own experience, and tracing through this wiring diagram, is indicating that we have a break there somewhere. For what it's worth, fuse 10 is also powered off the 30 terminal.
Customer: replied 6 years ago.

Voltage on #10 fuse, 10.66. Battery at 12.27. Steep drop.


This is my son's car. He is running around mountains of Afghan and shipped the car to me inop to try to get it running. I just got more info out of him. He and his buddies chipped the car, and they put an aftermarket adjustable Mass Airflow Sensor on it. They did not chop into any wiring, but...My kid ran the car over the factory settings of 130 MPH which may have engaged the fuel kill which is how the car protects itself from a dumba## XXXXX my kid trying to blow it up. According to manual, the car has a 130 MPH kill system in it which shuts down fuel. Wonder if the aftermarket chip bypassed some of this system, but another part of it is engaged? Car died on him in traffic a couple weeks after his high speed run. Can find no mention anywhere on the nuts/bolts of this system, but with the voltage all over the place, no obvious damage or broken wires, gotta be a computer or sensor somewhere that is unhappy. Any way to get some info on this? Audi dealer here in Phoenix are horse's patooeys.

Expert:  AudiDoc replied 6 years ago.

Well, I do a lot of go-fast aftermarket stuff on Audis, but if the software/chip is one of the reputable ones (GIAC/APR/O.CT), then that's not going to have any effect at all on regular, everyday drivability. Yes, the stock car/ECU does have a fuel cut, but that is very temporary, meaning it kicks in at that preprogrammed speed, and once you drop under it, injectors are firing again. Most chip tuners do tune out this limiter.


The aftermarket adjustable MAF is a new one to me. I do a lot of Audi performance work and have never even heard of that.


So, the eye opener is that massive voltage drop to #10. Have you pulled the rear covers off of either the relay or fuse panel?