How do you reset the check engine light on a 2004 Audi A4?

How do you reset the check engine light on a 2004 Audi A4?

Audi A4 B8: How to Reset Check Engine Light

  1. Step 1 – Locate your battery.
  2. Step 2 – Remove negative terminal.
  3. Step 3 – Refit negative terminal and start car.

How do you change an oxygen sensor on an Audi a4?


  1. Park, your Audi, set the parking brakes, and open the hood.
  2. Disconnect the negative battery terminal.
  3. Locate the oxygen sensor on your Audi.
  4. Disconnect the O2 sensor.
  5. Remove the sensor and place the oxygen sensor socket on the sensor and break it loose.

How many O2 sensors does an Audi a4 have?

The 2.0t engine utilizes two oxygen sensors: one in the exhaust manifold and one downstream, after the secondary catalytic converter. These are referred to as “Bank 1” and “Bank 2” sensors, respectively.

What are the symptoms of a faulty oxygen sensor?

Here are some of the most common signs that your oxygen sensor is bad.

  • A Glowing Check Engine Light. The bright orange Check Engine light in your dashboard will usually glow if you have a bad oxygen sensor.
  • Bad Gas Mileage.
  • An Engine That Sounds Rough.
  • An Emissions Test Failure.
  • An Older Vehicle.

What to do if check engine light comes on on Audi A4?

The best thing to do is invest in a diagnostic tool like Vagcom or any generic scanner. This would help in determining what is wrong with the engine by tell you the error code. There are hundreds of Audi A4 check engine light codes each for a different error.

Why is my O2 sensor not working in my Audi A4?

Of all the sensors equipped in your vehicle, the O2 sensors may have it the hardest. They deal with super hot exhaust that can cover them in deposits that can leave them ineffective. The heat of the exhaust can also bake the wiring going to/from them over time.

Why is my Audi A4 running rough at idle?

If a coil pack goes bad, it’ll cause a misfire and rough idle condition. Really, your A4 will be running rougher at any RPM, but a misfire will be most pronounced at idle.

Why does my Audi A4 B8 have a check engine light?

This article applies to the Audi A4 B8 (2009-2015). That check engine light can be a pesky bugger. It’s trying to help by alerting you of a potential problem, but without a code reader, you’re speaking different languages. Fortunately, unless that CEL is flashing, it is usually safe to drive the car home.

How do you reset check engine light on Audi A4?

Trunk-mounted battery location. Using your 10mm wrench, or ratchet, remove the negative (black) terminal from the battery. Wedge the terminal between the false floor, or otherwise secure it away from the battery. The goal is to keep the terminal from making contact. Wait approximately 15-20 minutes.

Can a OBD2 scanner read an Audi fault code?

Knowing which scanner to use to read Audi fault codes may be the most difficult part. Level 1 OBD2 scanners can only be used to retrieve fault codes from your Audi Engine Control Unit (ECU). Those are faults that trigger the Check Engine warning light on the dashboard.

What does the low battery charge light mean on an Audi A4?

Audi A4 low battery charge dashboard warning light Low battery charge If the battery power drops to a level where problems may be encountered when starting the engine, the low battery power charge light will illuminate .