Description And Operation: Operation: Pre-Heating

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.

Pre-heat is the length of time the glow plugs operate prior to engine cranking. The PCM controls the pre-heat time based on ECT sensor output and Barometric pressure (BARO). The pre-heat duration is extended if the coolant temperature is low and/or the barometric pressure is low (at altitude).

When the stop/start switch is pressed while the brake pedal is being pressed, the PCM calculates any required glow plug heating times and, if heating is required, signals the glow plug control module, which supplies power to the glow plugs. When pre heating is required the PCM also sends a message to the Instrument Cluster (IC), on the FlexRay systems bus to the Body Control Module/Gateway Module (BCM/GWM). The BCM/GWM then forwards the message to the IC on the high speed Controller Area Network (CAN) chassis system bus to request illumination of the glow plug warning indicator. The glow plug warning indicator remains illuminated for the duration of the pre heating phase, until the PCM cranks the engine. If required, the glow plug control module supplies power to the glow plugs during cranking and for the duration of any post heating phase.

The Barometric pressure also has an influence on activation and deactivation of the glow plugs in the event of large altitude differences.