febi has highlighted the availability of an in demand Preheating Relay that can be required to solve an issue on many common diesel engines. 

febi 188175, Preheating Relay, fits various models from Dacia, Nissan, Opel /Vauxhall, and models with the Renault Engine: K9K (1.5 D), M9R (2.0 D), M9T (2.3D). 

Diesel engines do not rely on the glow plugs just to start the engine. With increasingly strict emissions standards the system has evolved, and the glow plugs are now also used to keep the combustion chamber at the optimum working temperature during post glow once the engine has started and to assist during the regeneration process of the diesel particulate filter.

The purpose of the preheating relay is to monitor and control the operation of the glow plugs. Using the information from the engine control module the preheating relay provides the correct current to preheat the glow plugs to enable the engine to be started from cold, while also determining when to switch the current to each individual glow plug on or off post warm up to optimise the combustion process.

While solid state relays are reliable, they can suffer from excessive heat, vibration, and chemical issues. Some of the symptoms of a failing or failed pre-heat relay include: the vehicle being hard to start in warm temperatures and almost impossible to start when cold, extended cranking time when attempting to start the engine, increased fuel consumption and the appearance of white smoke from the exhaust because of incomplete combustion.

Some common fault codes which are associated with a relay failure are:

• P0383 – Glow plug control module – circuit low
• P0384 – Glow plug control module – circuit high
• P0380 – Glow plugs circuit A – malfunction
• P0382 – Glow plugs circuit B – malfunction

To solve this issue febi offers a replacement Preheating Relay. This is cost effective and readily available from febi stockists.