Glow Plug

WARNING: This page is about a different car, the 2018 Land Rover Range Rover, 2017 Land Rover Range Rover, and 2016 Land Rover Range Rover. However, it is still accessible from the selected car via links, so may be relevant.

The ceramic sheathed element glow plugs are made from a heat-resistant, electrically conductive ceramic material. The ceramic sheathed-element glow plugs outer layer is heated directly and is self regulating. The self-regulation allows the resistance of the sheathed element to automatically increase as the heat increases preventing the glow plug from overheating. In addition, during the heating process and under the control of the glow plug relay, the glow plugs can be operated above their nominal voltages. This permits heat-up speeds of 1000°C (1832°F) <2 seconds. The sheathed-element glow plugs reach a maximum glow temperature of 1300°C (2372°F) and can hold a temperature of 1250°C (2282°F) for several minutes after the first-start glow or at intervening times.

Each cylinder bank has a separate harness connecting the three glow plugs. The harness connects into the engine wiring harness and each harness has a connector block which attaches to each of the glow plugs for that bank.

The glow plug control module receives a permanent primary battery supply via fuses in the Battery Junction Box (BJB) and the Auxiliary Junction Box (AJB) The glow plug control module also receives a switched power supply from the PCM relay in the Engine Junction Box (EJB). Operation of the glow plug control module is controlled by the PCM, which also controls the illumination of the glow plug warning indicator in the instrument Cluster (IC).

The system has been designed as a low-voltage glow system. At 7 volts, the nominal voltage of the sheathed-element glow plugs is significantly lower than the 12 volts of the main electrical circuit. The electronic glow plug control module matches the voltage to the sheathed-element glow plugs and controls their glow temperature precisely to the specific requirements of the engine. This produces the optimum glow temperature even when the main circuit voltage is interrupted during engine starting. The lower power consumption of the ceramic glow plugs and their time-staggered activation reduce to a minimum the peak load on the main circuit during the cold start and immediate post-start periods.

In the event of glow plug failure, the engine may be difficult to start and excessive smoke emissions may be observed after starting.