Audi Check Engine Light ON Troubleshooting

If your Audi Check Engine Light (CEL) is ON don't panic. The problem may not be as severe as you may think. When Audi CEL turns on be that an A1 A3 A4 A5 A6 A7 Q3 Q5 Q7 TT, it means that a fault code (Diagnostic Trouble Code / DTC) is stored in the Engine Control Unit (ECU). No need to schedule an appointment with your mechanic to diagnose CEL when it is so easy to read the codes yourself. Retrieving Audi check engine codes is so simple that you can perform in your driveway. You need a Level 1 OBD-II scanner some of which cost as little as $15. Take a few minutes to read this guide to learn about the common problems that can trigger Audi CEL and how to diagnose the problem yourself.

The cause of Audi check engine light can be something as simple as a loose gas cap to a sign that a serious engine or transmission problem is underway.

Common causes of Audi Check Engine Light include:

• Loose Gas Cap ( No symptoms)
• Oxygen Sensor
• Worn spark plugs (Engine misfire)
• Ignition Coils / Coilpacks (Engine shaking)
• Vacuum leaks (Intake Air System Leak from cracked and loose hoses)
• Bad catalytic converter (Catalyst Efficiency Below Threshold)
• Low-quality gas
• Turbo Problem
• Ignition Control Module

If your Audi check engine light comes on and there are no other symptoms, the first thing that you should do is tighten the gas cap. If gas cap triggered the check engine light, within two to three days of normal driving the light will reset itself. No need to use a scanner to reset the light. If after a couple of days the CEL remains on you will need to read the codes. Don't ignore Audi CEL even if the car drives fine. Follow the instructions below to learn how to read and clear Audi fault codes from the Engine Control Unit. 

Audi Check Engine Light Flashing

If your Audi check engine light is flashing it indicates that there is an engine misfire. We would not recommend driving an Audi if the engine is shaking. It is better to have the car towed to prevent serious engine problems. If your Audi CEL light is flashing, it indicates that the problem is more serious. Under these conditions, the car may also go into limp mode.

Audi shaking is often caused by a worn spark plug, bad ignition coil, Ignition Control Module (ICM), or bad catalytic converter.

Read Codes / Reset  Audi Check Engine Light

Reading and clearing Audi check engine light is very simple. Don't clear Audi check engine light without fixing the problem. You need to figure out why the CEL turned on. Once you find what caused CEL to come on, fix the underlying problem. Often we see people disconnect the battery or use a scanner to clear Audi check engine light. Clearing Audi check engine light does not solve the problem. The light will come back on within a few days if the problem isn't fixed. In fact, if you fix the problem that caused your Audi check engine light to come on but didn't clear the light, the CEL will reset on its own typically within 5 or 6 driving cycles.

Instructions

To read Audi check engine light as outlined in this guide, you will need an OBD-II Scanner. Any scanner on the list will be able to retrieve the fault codes. Scanners that are designed specifically for Audi such as Audi VAG COM Scan Tool will provide more accurate descriptions. 

Step 1

Locate OBD-2 port under the dashboard on the driver's side. This is a 16-pin port. All 1996 and newer Audi vehicles have this port.

Step 2

Plug in your OBD-2 Scanner into the OBD2 port.

Step 3

Turn key to position II. All the dashboard lights will turn on. Do not start the vehicle.

If your Audi has Start/Stop button you will need to press the Start button without pressing the brake pedal.

Step 4

Allow the OBD2 scanner to turn on and connect to your Audi Engine Control Unit (ECU).

Step 5

Read Audi check engine light codes from the Engine Control Unit (ECU)

Audi CEL Repair Cost

Average cost to fix Audi check engine light can range from $150 to $500. It is difficult to determine the exact cost to fix Audi check engine light without pulling the codes first. If you take your car to the mechanic, there is a diagnostic fee (reading codes from the ECU which you can also perform yourself) and the repair fee which depends on the problem. Auto parts stores such as Auto Zone or Advance Auto Parts may scan the codes for free. 

If you call any Audi mechanic they will ask you to bring the car in for a check-up. Or you can get an OBD-II scanner and retrieve the codes yourself. Even if you don't plan on fixing the problem yourself, you will have a better idea of what is wrong. Once you retrieve the codes you will know if the problem is a loose gas cap or an expensive repair. Sometimes it can be challenging for a shop to diagnose the problem because the issue can be intermittent and can not be duplicated when you are at the shop. If you have a scanner with you, plug it into the OBD-2 port and retrieve the codes when you experience the problem.