I have a 2012 Audi A6 3.0 TDI V6 with 117,000 miles on the clock. 

After getting home from work, I experienced a misfire that felt like sputtering. Upon arriving home, the car stalled. I tried to start it again, and while it did start, it idled roughly and there was no response from the accelerator pedal. I was only able to limp about 10 meters into my driveway.

This morning, I attempted to start the car using the button, as it does not have a key ignition. It started for a short time but then shook and became unresponsive to the accelerator pedal again. Then it died.

Interestingly, there are no error codes or warning lights on the dashboard.

I was informed by my dealer that I need a new fuel injector, but I'm not convinced that’s the issue. The battery voltage is at 12.6, so it seems to be functioning properly.

Could the EGR be blocked? Usually, that would trigger a code, but it hasn’t.

Is it possible that a blown fuse is affecting the starting?

Could the fuel injection pump have failed?

I don't feel confident in relying on my garage until I can conduct further investigation issue.

 

 

Edited August 21, 2025Aug 21 by Johnbob1970

Did your garage present any evidence to support its diagnosis? A print from its diagnostic machine for example?

If you really don't trust the garage, take the car elsewhere for a second opinion.

The garage showed me this code. He said to test the injectors' return fuel chart tube; 2 of 4 injectors are bad because the diesel returned did not match the same level as the other four injectors. Does this provide enough evidence for the engine running for 30 seconds, then dying? I mean, the engine could run on 4 out of 6 cylinders. I am going to see a fuel specialist tomorrow for a second opinion.

1 hour ago, Johnbob1970 said:

The garage showed me this code. He said to test the injectors' return fuel chart tube; 2 of 4 injectors are bad because the diesel returned did not match the same level as the other four injectors. Does this provide enough evidence for the engine running for 30 seconds, then dying? I mean, the engine could run on 4 out of 6 cylinders. I am going to see a fuel specialist tomorrow for a second opinion.

Hi if the garage did the leak back test that is conclusive proof of your problem, if the car has done a lot of miles the offending injectors need replacing, most injector problems on low milage vehicles a couple of years old are normally down to cheap/bad fuel, it wont just run on four cylinders as the ECU wont suffer that lack of firing balance. Also the p51d code probably means the starter is on its way out.

Steve.

I got a second opinion from another garage, and they said that the issue doesn't resemble diesel injector problems. They performed the same tests as the first garage, and the return fuel from the injector chart looked average.

 

They believe the crankcase sensor had failed. After installing a new one, the car started running smoothly.

 

However, my injection system still needs attention as soon as possible.

If anyone had the same issue, look at the crankcase sensor location, passenger side (UK), front wheel arch plastic needs to be removed. It's there.