Question about Audi A4

Open Question

Intermittent emission control light audi a4

Emission control light came on about 13 months ago. Local garage ran diagnostic and reset the faults. Problem rectified. About 2 months ago the problem returned. Decided to go down the route of running proper diagnostic to determine exactly what work was required. Possible cause was explained as the NOX sensor. Before running the diagnostic the light mysteriously went out. Its been fine for about 3 weeks but has now come back on again.

Posted by on


5 Suggested Answers

  • 2 Answers

SOURCE: I have freestanding Series 8 dishwasher. Lately during the filling cycle water hammer is occurring. How can this be resolved

A 6ya expert can help you resolve that issue over the phone in a minute or two.
Best thing about this new service is that you are never placed on hold and get to talk to real repairmen in the US.
The service is completely free and covers almost anything you can think of (from cars to computers, handyman, and even drones).
click here to download the app (for users in the US for now) and get all the help you need.
Good luck!

Posted on Jan 02, 2017

  • 5158 Answers


nothing really to do with your battery or coil pack.... if you happen to live in the states i hear that autozone will test the codes for free. have the codes tested and see what errors it shows.


Posted on Sep 26, 2008

  • 11896 Answers

SOURCE: 1993 Audi 100 CS with V6 sets emission control light

The egr valve may be faulty or leaking air. Otherwise you may have a plugged or cracked vacuum line or low vacuum pressure

Posted on Aug 20, 2009

  • 1 Answer

SOURCE: My Audi A4 air con is not blowing any air hot or

its the heater motor brushes....101% guarantee it.

They can be bought on ebay for £12.50

Posted on Feb 01, 2010

  • 2418 Answers

SOURCE: abs and engine fault light

If they are checking the system at the ECU and its telling them the sensors are bad, then you have a broken harness down stream of the ABS ECU. There has to be a brake in the harness to the rear wheel sensor(s). It is a brake in the harness or the end plug is not making good contact with the sensor contacts. Hope this helps.

Posted on Feb 23, 2011

Add Your Answer

Uploading: 0%


Complete. Click "Add" to insert your video. Add



Related Questions:

1 Answer

Emission control light came on and turbo stopped working on Audi A4

The computer on most cars will not allow the car to run at peak performance with engine codes on. It could prevent damage to the engine.

Jun 05, 2016 | 2011 Audi A4 1.8

1 Answer

Long story - 1st I had glow plug light & traction control lights on.hrottle pedal chaged & lights re-appeared after 2 days. Then the emission control light came on before I got to the audi...

U paid 290 euros and they did not fix it. I would go back and insist that either they fix it or return my Euros so I could take it to a competent mechanic.

Apr 03, 2017 | 2006 Audi A4

1 Answer

Hi. I have a 2004 Audi A3. PAst number of weeks a light Emission Control System and EPC light come on intermittantly. Sometimes when out for a journey, the car can cut out when stopped at lights and...

coolant temp sensor or airline.

I had the same problem, replaced the coolant temp sensor for £15 and reset the warning light. 2004 1.6 SE. I'll never go back to Audi for a service. They might as well wear balaclavas.

I still have some problems with the idling but I can live with it (or until I know the real reason) - After £100 diagnostic and me suggesting to them what it might be they said they could do nothing. Surely by the number of comments about the same problem it must be a known fault!

Oct 06, 2010 | 2005 Audi A3

1 Answer

1993 Audi 100 CS with V6 sets emission control light

The egr valve may be faulty or leaking air. Otherwise you may have a plugged or cracked vacuum line or low vacuum pressure

Aug 20, 2009 | Audi 100 Cars & Trucks

1 Answer

2005 Audi A4 Emission Control System Indicator Warning Light is on. What does that mean?

A vehicle's Emission Control Light is a generalized indicator that there is fault or possible malfunction in the vehicle's operating system. In some cases, these warning lights will come on if a gas cap is not fully closed. It could any one of a number of sensors such as the o2 sensor or map sensor. The thing to do is have a reputable mechanic/technician run a diagnostics test on the vehicle.

Aug 20, 2009 | 2005 Audi A4

1 Answer

Emission control system light on dash

audi a4 tdi Emission control system light on dash

Jun 02, 2009 | 2007 Audi A6 Avant Wagon

1 Answer

Audi aotomatic A4 1800 V Reg. Gearbox

have the garage do a driveability diagnostic interfacing with the gearbox and watch for torqe converter lock well as gear and speed changes tps values...

Jun 18, 2008 | 2000 Audi A4

Not finding what you are looking for?
Cars & Trucks Logo

Related Topics:

29 people viewed this question

Ask a Question

Usually answered in minutes!

Top Audi Experts

Colin Stickland
Colin Stickland

Level 3 Expert

22326 Answers


Level 3 Expert

78257 Answers

Thomas Perkins
Thomas Perkins

Level 3 Expert

14405 Answers

Are you an Audi Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides