Glow Plug Warning Light on VW Jetta Flashing - Symptoms, Causes & Solution

By Nick Marchenko, PhD

In the following guide, we assist you when the glow plug light on your VW Jetta is flashing or persistently illuminating during your drive. 

We will provide you with the causes, display the symptoms, and also take a look at the possible repair costs.

Diesel Engine Basics

Diesel engines feature electrically operated glow plugs that heat up when turning the ignition key or pressing the start button. Depending on the age of your vehicle and the outside temperature, this preheating process may take longer. If the glow plug light is constantly flashing, there is a problem with the vehicle.

Symptoms in the VW Jetta when the glow plug light is flashing:

- The yellow spiral (symbol of the glow plug light) does not extinguish after starting the engine, but remains illuminated or flashing persistently in the instrument cluster or speedometer.
- The engine judders when driving.
- A significant loss of power is noticeable.
- The car responds poorly to acceleration / possibly very delayed.
- The vehicle possibly switches into the emergency running program.
- The VW Jetta engine control light often illuminates as well.

Causes of a flashing glow plug light:

- Issues with the EGR valve.
- Fault in the throttle position sensor.
- Defect in the crankshaft sensor or a glow plug.
- Broken exhaust temperature sensor.
- Defective brake lights / a fault in the brake light switch.

Possible Solutions & Cost

The costs determined by us over the phone can greatly deviate from our standard values depending on your location, workshop, and the specific model of your vehicle. Thus, these details are provided without any guarantee.

We recommend you to read the error memory of your car yourself with an OBD2 Bluetooth adapter. This saves you the cost of this process in the workshop, and then you can draw conclusions about the fault yourself.

Nick Marchenko, PhD

Industrial Engineer & Automotive Content Specialist

Nick writes in-depth guides on car clubs, engine specs, vehicle ownership, and modifications, combining engineering knowledge with automotive passion.

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