Fuel pump relay and speed sensor and fuel filter
Asked by GuruCMY5Y Apr 03, 2019 at 11:52 AM about the 2011 Audi A4 2.0T quattro AWD
Question type: Maintenance & Repair
Engine stop on highway and will not start.
Can anyone tell me where the fuel pump relay located. Also the location of the
speed sensor and is the fuel filter part of the fuel pump assembly inside the
fuel tank or is it located outside the tank.
12 Answers
Hornet_2497 answered 5 years ago
Fuel pump relay and fuel pump fuse should be in the fuse box or power distribution box under the hood. The fuel pump in the gasoline tank has a brass screen, sort of a pre filter, but it normally does not clog. Your actual fuel filter will be on the fuel line near the tank, or maybe a little farther forward going to the engine compartment along that fuel line. A failed speed sensor should show a code/check engine light. It would likely be on the front transaxle shaft. If the car stopped suddenly, it is most likely a fuse or pump itself. Sometimes they restart after they cool. Or bang on the tank with your hand. It may run long enough to get to a shop without a tow truck.
Thanks Hornet Going to check for the pump fuse and relay now and let you know
Hornet_2497 answered 5 years ago
If your car has a lot of miles over 100K, you may have a broken (valve) timing belt. The engine will crank real fast, having no compression, it won't start up. That belt is not easy to access/inspect on the road. Have to take it in.
Timing belt and new teniometers installed about 5000 miles ago, when I open the door l can hear the pump humming under back seat for a few seconds but when trying to start cranking I don,t smell fuel
Hornet_2497 answered 5 years ago
Fuel pump must be okay, including fuses and relays. You normally won't smell fuel but check fuel pressure somewhere in the injector system. It can be checked while replacing fuel filter. If fuel system is okay, check for spark. Scan for codes too.
Checked for spark this morning and have spark . Going after the fuel filter next, although I have fuel at the plug I don’t think it is enough for the amount of times I cranked the engine. The only code I get is the camshaft sensor which has been changed twice that has always come on for months even when car runs great. I will follow up with you after filter change Thanks for the info.
Hornet_2497 answered 5 years ago
The camshaft sensor provides signal to the PCM to provide properly timed injector pulse. I would be wondering why that code keeps coming back. But anyway, check your fuel pressure near the injector rail. Low pressure would not be providing enough fuel to start/run even though some fuel is present. And Yes, a filter change would be the next thing to do. Good Luck.
Ok I went looking for the fuel filter and followed the lines from the tank to the engine compartment and there is no filter
Hornet_2497 answered 5 years ago
I looked up fuel filters for your car. There are two. One has three connectors which means it most likely would be near the tank. One line into the filter, two coming out. One line goes to the engine and the second would be a return line to the tank. This filter also contains the pressure regulator. There is another filter inside the tank, more than just that brass screen I mentioned earlier. I would keep looking for that external filter and replace it first because it is easier to reach. It might even be under the hood. But remember, if your fuel pressure is okay, don't worry about the filters for now.
We look let you know
The only unit that I found under the hood was what thought was the high pressure fuel pump 3 lines and pressure regulator on top, doesn’ Look like a filter for 2.0 TSFI ?
Was checking the fuel pump control module this morning and found that the voltage at the control module harness connector was 12 volts reconnected the harness to the control module and disconnect the fuel pump harness and found that there was only 6 volts coming from the fuel control module during crank the spec I am using states voltage should be within 2 volts of battery voltage if not replace fuel control module. I guess 6 volts will not drive the pump enough for proper pressure?