Description Of Causes For AUTOSTOP Blocking, VEA Generation 2

GENERAL 

The information in this document applies to VEA engines of generation 2. From structure week 2017- a vehicle may have either a engine of generation 1 or generation 2 installed.

HINT: If the vehicle is manufactured in a time period where engines of both generations where available see the parameter "Engine generation" under Diagnostics/Components/Engine Control Module (ECM)/Parameters to determine the generation of the engine. (The parameter is only available in vehicles with structure week 2017-.) 

The Engine Control Module (ECM) detects and saves information about which causes have blocked the automatic start/stop of engine function and what has caused the system to request autostart in autostop mode. This document describes the causes of blocked autostop.

HINT: If Engine Control Module (ECM) and/or Central Electronic Module (CEM) detected faults and stored fault codes for components/functions related to Automatic start/stop of engine, it is not certain that the event has been stored as cause. 

CAUSES FOR AUTOSTOP BLOCKING 

Climate system 

The climate system can inhibit an autostop if the engine needs to be running to ensure the required environment in the passenger compartment.

Power management 

The Central Electronics Module (CEM) can inhibit an autostop if the capacity of the batteries is considered to be insufficient. For example in case of a low state of charge or low battery temperature.

Starter motor 

The Engine Control Module (ECM) can inhibit an autostop if the calculated temperature of the starter motor is too high. This might occur if many automatic start/stops has been made in a short period of time.

Engine cooling fan 

The Engine Control Module (ECM) can inhibit an autostop if a stopped engine will require an engine cooling fan speed at 100 % to get sufficient cooling. In that case the engine will be kept running to get a better coolant circulation.

Engine management system 

The Engine Control Module (ECM) can inhibit an autostop for a number of reasons when it is not considered optimal to stop the engine. Examples of such reasons is too high or low coolant temperature, combustion of soot in the particle filter and warm up of the catalytic converter.

Fault detected by engine management system 

The Engine Control Module (ECM) can inhibit an autostop if it has detected a fault that might impact the automatic start/stop functionality.

Hard braking 

Autostop will be inhibited if a hard braking is detected recently. This can be a panic brake or a result of sporty driving.

Braking with ABS engagement 

Autostop will be inhibited if ABS system has been activated recently. This also applies if the ABS pump motor has been actuated on request from the electronic stability system.

Brake system 

The brake system can inhibit an autostop if it has detected a condition that might impact the automatic start/stop functionality.

Brake vacuum 

The brake system can inhibit an autostop if the brake vacuum is not sufficient.

ABS failure 

The brake system can inhibit an autostop if it has detected a fault that might impact the automatic start/stop functionality.

Gear position "R" 

Autostop will be inhibited if the reverse gear is engaged. This reason will also be stored if the vehicle is allowed to roll backwards.

Gear position sport/manual 

Autostop will be inhibited if the gear selector is in manual shifting mode.

Transmission system 

The Transmission Control Module (TCM) can inhibit an autostop for a number of reasons when it is not considered optimal to stop the engine. Examples of such reasons is too low transmission oil temperature or an ongoing gear shift.

Driver not belted 

Autostop will be inhibited if the driver is not using the seat belt, unless the gear selector is in gear position P.

Driver door open 

Autostop will be inhibited if the driver door is open.

Hood open 

Autostop will be inhibited if the hood is open.

Drive mode 

The driver has chosen a drive mode that inactivates the automatic start/stop function.

Start/stop manually inactivated 

The driver has manually turned off the automatic start/stop function.

Steering 

Autostop will be inhibited if the steering wheel is turned quickly or if the steering gear is close to its end positions.

Park assist 

Autostop will be inhibited while the parallel parking system is active.

Vehicle speed 

Autostop will be inhibited when a number of consecutive start/stop cycles has been performed. When the vehicle has reaches a certain speed autostops will be available again.

Trailer connected 

Autostop will be inhibited if a trailer is connected to the vehicle.

Altitude/pressure 

Autostop will be inhibited if the vehicle is at too high altitude.

Slope 

Autostop will be inhibited if the vehicle is on a slope with too large gradient.

Ambient temperature 

Autostop will be inhibited if the ambient temperature is too high or too low.