People often mistake a glow plug flashing light as a “Glow plug/s issue” but in fact, it’s not the case.
The flashing light is actually the same as the check engine light on a diesel Audi and can be caused by different things.
In this article, I am going to discuss what the Audi glow plug light flashing means, the possible leading cause, and things you can do to solve the problem.
Audi Glow Plug Light Meaning
There are three scenarios where the glow plug light (coil-like symbol) will come on your Audi’s dashboard.
Depending on what happens when you start and drive your Audi will determine if there is an issue with the vehicle or not.
These scenarios are:
1. Glow Plug Light Comes on and then Turns off
If you see the glow plug light when you turn on the car and as soon as start driving the light turns off, then this is normal.
Since your Audi has a diesel engine, glow plugs play a crucial role in n starting and driving your car.
The glow plugs are small heating elements that help ignite the diesel fuel when you start the engine.
Once the glow plugs have done their job, they turn off automatically.
This is especially true for cold days and in the morning when you first start driving.
If your Audi’s glow plug light comes on and then turns off after a few minutes of driving, then there is no issue with the car or its engine.
2. Glow Plug Light Comes on and Stays On
If the glow plug light remains on while you are driving, this means that there is an issue with one or more glow plugs that need to be replaced.
If your Audi’s glow plug light comes on and stays on, then chances are you need to get one or more glow plugs replaced.
3. Glow Plug Light is Flashing
If your Audi’s glow plug light is flashing, then this a more like a MIL light and needs to be diagnosed.
But from my experience working on a lot of diesel Audi’s with a similar issue, I will list the most common causes of the glow plug light flashing.
Common Glow Plug Flashing Symptoms
Here are a few things you may notice when your Audi glow plug light starts flashing.
- Limp Mode
- Loss of Acceleration Power
- The Car takes longer to start
- Excessive Engine Vibration
- Black Smoke Coming out of the Exhaust
- Engine stalling
Audi Glow Plug Light Flashing Common Causes
Now, let’s look at the most common causes of the glow plug light flashing, ranked from the most common to the least.
1. Blocked DPF (Diesel Particulate Filter)
If your Audi’s DPF is clogged up, this will be the likely cause of the flashing glow plug light. When a DPF becomes blocked, it can no longer filter out particulate matter from the exhaust gasses and requires replacement.
The solution to this would be to get it cleaned or replace the Diesel Particulate Filter. I personally recommend the former since it’s cheaper and more effective.
2. Malfunctioning EGR Valve
The Exhaust Gas Recirculation (EGR) valve is a system that controls the amount of exhaust gas that enters your engine.
If it malfunctions, the EGR valve won’t be able to regulate how much exhaust gas re-enters the combustion chamber, which can cause problems with the motor and emissions.
The solution to this would be to replace the EGR valve or get an EGR delete kit and mapping if you looking for a more permanent solution.
3. Dirty/Bad Throttle Body
Another common cause for a flashing glow plug light on an Audi is a bad or dirty Throttle body.
The throttle body is responsible for regulating the amount of air that enters your engine.
These can get clogged on Audi’s due to the fact that they are very prone to exhaust gases that come up the engine when you turn off your car.
If this problem is left unchecked, it can cause your engine not to run as efficiently, which will lead to poor performance and fuel economy.
The solution to this problem is to replace the throttle body, which can be very expensive.
Another option would be to clean it out yourself using a general-purpose oil.
4. Bad Brake Light Switch
As I mentioned above that when the glow plug flashes it can be caused by a lot of different things and a bad brake light switch is a common cause as well.
This is because the brake light switch is responsible for turning on your brake lights when you depress your pedal.
If this switch fails, it can cause the glow plug light to flash and not just when the engine is cold but also when it’s warm.
5. Faulty Crankshaft Sensor
A faulty crankshaft sensor can cause the glow plug light to flash as well.
This is because the crankshaft sensor is responsible for sending a signal to your engine control module (ECM), which then tells it when to fire up the glow plugs.
The fix for this would be to replace the crankshaft sensor, it is relatively inexpensive to do fortunately.
6. Bad EGR Solenoid
A bad EGR solenoid can cause the glow plug light to flash.
This is because it’s responsible for opening and closing your exhaust gas recirculation (EGR) valve, which allows fresh air into the exhaust manifold and also prevents contaminants from getting into your engine when you turn on your heater.
If this valve doesn’t open or close as needed, it could throw off the operation of other components in your vehicle such as the glow plugs.
The solution for this is to replace the EGR solenoid. It’s an inexpensive part to replace, but you’ll need to have a certified technician do it for you.
To add to this list lastly would be bad glow plugs but it is rarely the cause from my experience.
I personally recommend that you take your Audi to any qualified garage/dealer and get a diagnostic scan to have a clear picture of the main culprit instead of throwing parts at your car.