Audi
Type:
    Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled
Description:
    Glow plug warning lamp - open circuit/short to ground
Cause:
    Bulb, wiring open circuit/short to ground

GM
Type:
    Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled
Description:
    Engine Oil Level Switch Circuit Conditions
Cause:
    No TP or VSS codes set, engine speed over 2000 rpm, throttle position over 5%, VSS input over 3 mph, vehicle in steady state cruise (no lateral acceleration detected), then the PCM detected a low EOL switch signal (low voltage), and/or no transition of the EOL switch for at least 8 seconds

Volkswagen
Type:
    Powertrain - Manufacturer Controlled DTC - Manufacturer Controlled
Description:
    Glow plug warning lamp - open circuit/short to ground
Cause:
    Bulb, wiring open circuit/short to ground