Adjusting pre-glow time on VAG TDIs with VCDS (Articles)

Wann ist es überhaupt sinnvoll, die Vorglühzeit der Glühkerzen zu ändern?

Normally not, because in 'standard operation', starting problems or white smoke in TDIs usually have their cause in engine faults that must be addressed first. Examples include an adjustable static injection timing, faulty glow plugs, or a defective coolant temperature sensor.

However, there are cases where extending the preheating time makes sense: when operating the TDI engine with vegetable oil (rapeseed oil) or, possibly, with biodiesel. Depending on the engine and fuel, the standard preheating may not be sufficient to achieve an acceptable cold start. Für diese Fälle ist nachfolgende Anleitung gedacht.

To change the preheating time, the following steps are necessary:

• The engine coolant temperature must be low enough for the glow plugs to activate, e.g., 5°C. Otherwise, no changes will be observed.
Turn on the vehicle's ignition.
Connect to the engine control unit (01) using VCDS.
Perform a login with the code 12233.
Go to adaptation group 12 via control unit adaptation.
Change the default value (e.g., 3276) to 32700 and save the value.
• 8)Disconnect from the engine control unit.
• Turn off the ignition and wait a few seconds.
• Go back into the engine control unit and perform the same steps as above. Of course, a new value doesn't always have to be saved. In field 2 of group 12, you can now see the preheating time, which was active after the last "ignition on".

This eliminates the fear of cold starting while idling below 0°C!