Vehicles With Auto Stop/Start System

WARNING: This page is about a different car, the 2019 Jaguar XE. However, it is still accessible from the selected car via links, so may be relevant.

At the beginning of a drive cycle, when the ignition switch is operated, the auto stop/start system operates in the same way as on vehicles without auto stop/start system.

The auto stop/start system is controlled by the Powertrain Control Module (PCM) and the Body Control Module/Gateway Module (BCM/GWM) via FlexRay bus and signals from other system components and modules to determine the correct conditions for system operation. The auto stop/start system detects when it is appropriate to stop and start the engine.

The auto stop/start system automatically stops the engine in appropriate conditions, resulting in zero tailpipe emissions and saving fuel when the vehicle is stationary. When the driver is ready to move off, the engine instantly restarts. Sophisticated controls make sure that the auto stop/start system does not compromise the needs of either the driver or the vehicle.

The auto stop/start system can be enabled/disabled using the auto stop/start switch in the floor console.

Software within the PCM controls the operation of the auto stop/start system. In addition to its own dedicated components the auto stop/start system encompasses many other vehicle systems.

Complex technology interconnects these systems and makes sure that all the necessary conditions are satisfied by monitoring, among others:

Brake hydraulic system pressure.
Transmission Control Switch (TCS) position.
Road speed.
The state of vital vehicle systems.
Environmental conditions.

The driver will be notified that the engine stops by the auto stop/start warning indicator being illuminated in the Instrument Cluster (IC). Other warnings normally associated with an engine stoppage. For example the ignition and low oil pressure indicators, are suppressed so will not illuminate during an engine stoppage in an auto stop/start cycle.

The following conditions will prevent an auto stop:

A steering wheel paddle switch has been used to select a gear (Transmission Commandshift Mode).
The ambient air temperature is outside the range of 2 °C to 40 °C (36 °F to 104 °F).
The ambient air pressure is below 720 hPa.
The engine coolant temperature is outside the range of 20 °C to 107 °C (68 °F to 224 °F).
Brake vacuum is less than the threshold value.
The hood is open.
The driver door is open.
The driver seatbelt is not fastened.
High demand from the climate control system requires the engine to be running, for example, windshield demist selected.
The battery charge is low.
The Hill Descent Control (HDC) is active.
The level in the fuel tank is too low (approximately 6 liters remaining in tank).
The auto stop/start system is disabled using the auto stop/start switch.

While the vehicle is stationary, if a condition that prevented an auto stop is removed the PCM automatically performs an auto stop.

The PCM automatically restarts the engine when one of the following occurs:

The brake pedal is released with Drive (D) or Sport (S) selected on the TCS.
The accelerator pedal is pressed.
A paddle switch is used to select a gear.
Reverse (R) is selected on the TCS.
Climate control system demand increases.
The vehicle speed exceeds approximately 1 km/h (0.5 mph).
Battery state of charge is near its lower threshold.
Brake vacuum reduces below the threshold value.
The auto stop/start system is disabled using the auto stop/start switch.

NOTE: When the brake pedal is released during an auto restart the Anti-lock Brake System (ABS) control module briefly applies the brakes to hold the vehicle stationary until the engine has restarted.

The following will prevent an auto restart and require use of the ignition switch to restart the engine:

The hood is open.
The driver seatbelt is not fastened.