Glow Plug System, Checking

WARNING: This page is about a different car, the 2014 Audi A8 Quattro. However, it is still accessible from the selected car via links, so may be relevant.

The Automatic Glow Time Control Module -J179- controls the pre-glow system. The control module has On Board Diagnostic (OBD) capable systems.
The Automatic Glow Time Control Module -- is located in the relay and fuse panel inside the engine compartment E-box on the right side. Refer to appropriate Wiring Diagram.
If there is a malfunction in the preglow system, a fault will be stored in the Engine Control Module -J623-.
Checking the preglow system is explained in "Guided Fault Finding".
Electronically controlled glow plugs with a separate glow plug control module were installed in order to reach a quick starting function.
Each glow plug is controlled and diagnosed individually.

NOTE:

Wait 60 seconds after each glow plug control module output diagnostic test. The ignition must remain switched on.

If the 60 second waiting period is not observed, (if the ignition switched off and then back on again), the glow plugs could be damaged (by a repeated preglow).

The glow plug control depends on the coolant temperature.