(TA100-1115) "Service vehicle soon" message and DTC on glow plugs: Background

During certain driving conditions increased soot build up in the cylinder pressure sensor can block the pressure signal and cause the diagnostics to set fault codes. The pressure sensor is located in the glow plug.

Typical fault codes are:

P0399, P039C, P039D, P03A3, P03A6, P03A7, P03AD, P03B0, P03B1, P03B7, P03BA or P03BB. DTC P1325 might also be present.