This TSB applies to 2011-2012 VW Golf, Jetta, Jetta Sportwagon and Golf Wagon, and 2012 Passat vehicles, all equipped with the 2.0L diesel engine. DTCs P0671, P0672, P0673 and/or P0674 (Cyl 1-4 glow plug circuits) may be stored in ECM fault memory.
An internal hardware issue of the glow plug relay may cause an over-voltage supply to the glow plugs, damaging the heating element.
Improved glow plug relays have been implemented in production and spare parts. If the above-mentioned DTCs are stored, replace the glow plug relay and the affected glow plug.