Land Rover Discovery: Vehicles Without Auto Stop / Start System

Engine cranking is requested when the stop/start switch is pressed and the driver has depressed the brake pedal. When engine cranking is requested, the ECM checks that a valid key code has been received and the transmission is in Park (P) or Neutral (N) before granting the crank request.

Once engine cranking has been granted, the ECM energizes the starter relay located in the right EJB. The closing of the starter relay contacts causes battery voltage to be applied to the starter solenoid in the starter motor. The solenoid is energized and the pinion gear is pushed to engage with the drive plate ring gear. Simultaneously, the starter solenoid contacts close, causing current to flow into the motor brushes and armature. The armature rotational force is transferred to the drive plate ring gear through the pinion gear, rotates the drive plate and starts the engine.

When the engine reaches self-sustaining operating speed, the ECM deenergizes the starter relay to disconnect power from the starter motor and disengage the pinion gear from the drive plate ring gear.

VEHICLES WITH AUTO STOP/START SYSTEM

Engine cranking is requested when the stop/start switch is pressed and the driver has depressed the brake pedal. When engine cranking is requested, the ECM checks that a valid key code has been received and the transmission is in Park (P) or Neutral (N) before granting the crank request.

Once engine cranking has been granted, the ECM energizes the starter relay located in the right EJB. The closing of the starter relay contacts causes battery voltage to be applied to the motor solenoid, which energizes and causes current to flow into the motor brushes and armature. The armature rotational force is transferred to the drive plate ring gear through the pinion gear, rotates the drive plate and starts the engine.

When the engine reaches self-sustaining operating speed, the ECM then de-energizes the starter relay to disconnect power from the starter motor and disengage the pinion gear from the drive plate ring gear.

Auto Stop/Start System

The auto stop/start system automatically shuts down the engine in appropriate conditions, resulting in zero tailpipe emissions and saving fuel that would otherwise be used idling the engine when stationary. When the driver is ready to move off, the engine instantly restarts. Sophisticated controls ensure that the stop/start system does not compromise the needs of either the driver or the vehicle.

By default the stop/start system is enabled at the start of each ignition cycle. The auto stop/start system can be enabled/disabled using the auto stop/start switch in the front floor console. The LED in the auto stop/start switch is extinguished when the stop/start system is disabled.

Software within the ECM controls the operation of the 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 ensures 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.

If all necessary conditions are satisfied the stop/start system will automatically stop the engine if:

• The vehicle stops from a speed greater than 4 km/h (2.5 mph)
• Sufficient pressure is applied to the brake pedal to ensure the vehicle is stationary and the transmission is in Drive (D) or Sport (S), or the vehicle is stationary and Park (P) or Neutral (N) selected on the TCS.

The driver will be notified that the engine is shut down by the auto stop/start warning indicator being illuminated in the IC. Other warnings normally associated with an engine shut down, for example the ignition and low oil pressure indicators, are suppressed so will not illuminate during an engine shut down in a stop/start cycle.

To restart the engine, the driver simply releases the brake pedal or pressesthe accelerator pedal. The ECM then operates the starter motor and starts the engine.

If system conditions are not approved by the ECM the auto stop/start system will not behave as expected, examples of this are:

• System inhibit: the engine will continue running even though the vehicle is stationary with the brake pedal pressed and the TCS in Drive (D) or Sport (S), or the vehicle is stationary and the TCS is in Park (P) or Neutral (N)
• System override: the engine has been stopped by the stop/start system but conditions have since changed, this will activate an early automatic engine restart.

These interventions are to ensure the auto stop/start system does not impact on:

• Vehicle and occupant safety
• Driver requirements
• Occupant comfort
• Vehicle on-road and off-road capabilities.

Although the main control logic for stop/start operation resides in the ECM, the CJB has software to communicate engine shut down inhibits to the ECM. In some instances, depending on the reason for the system intervention the driver will be notified, via the message center, of the reason for the intervention.

Stop Inhibitors

The following conditions will prevent the auto stop/start system from stopping the engine:

Driver effected stop inhibitors

• Driver switches off the auto stop/start system
• A steering wheel paddle switch has been used to select a gear
• Brake pedal not fully pressed
• Accelerator pedal depressed
• Hood is open
• Driver door is open
• Driver seatbelt is not fastened
• Climate control system used above calibrated threshold
• Windshield demist is operating
• Trailer electrical connection detected

Vehicle system effected stop inhibitors

• Brake booster vacuum below threshold
• Battery cold cranking capability below threshold
• Battery state of charge is low
• Catalytic converter outside either pre or post calibration range
• Engine coolant temperature below threshold
• Engine oil temperature below threshold.

Environmental effected stop inhibitors

• Ambient air temperature above 40 ºC (104 ºF)
• Ambient air temperature below 0 ºC (32 ºF).

Start Initiators

When the engine has shut down within an auto stop/start cycle the following conditions will initiate an early restart within the same auto stop/start cycle:

• Driver effected start initiators
• Driver switches off the auto stop/start system
• The accelerator pedal is pressed
• A steering wheel paddle switch is operated to select a gear
• Reverse (R) is selected on the TCS
• Vehicle speed above calibrated threshold 3 km/h (2 mph) (a restart will only occur if the transmission is in neutral and the driver is present, for example, the driver seatbelt remains fastened and the driver door remains latched)
• Brake booster vacuum below threshold (driver operating brake pedal)
• A higher climate control blower speed is selected
• Windshield demist is activated.

Vehicle system effected start initiators

• Battery cranking capability is near its lower threshold
• Battery state of charge is near its lower threshold
• Windshield demist activates
• The passenger compartment temperature decreases below or increases above the selected thresholds.

Environmental effected start initiators

• Ambient air temperature rises above 40 ºC (104 ºF)
• Ambient air temperature falls below 0 ºC (32 ºF).

The maximum engine stop duration is 270 seconds, after this duration the vehicle will restart.

Start Inhibitors

When the engine has shut down within a stop/start cycle certain conditions will prevent an automatic restart:

Driver effected start inhibitors

• Hood has been opened
• Driver seatbelt is disengaged (this is an automatic start inhibitor therefore the engine can be restarted by depressing the clutch pedal)
• Driver door is unlatched (this is an automatic start inhibitor therefore the engine can be restarted by depressing the clutch pedal).

Vehicle system inhibitor

• There is a system fault.

INPUT/ OUTPUT DIAGRAM

INPUT/OUTPUT DIAGRAM - SHEET 1 OF 2 - STARTING SYSTEM WITHOUT AUTO STOP/START SYSTEM

A = HARDWIRED; AO = MEDIUM SPEED CONTROLLER AREA NETWORK (MS-CAN) BODY SYSTEMS BUS.

1. Engine Control Module (ECM)
2. Stop/start switch
3. Central Junction Box (CJB)
4. Keyless Vehicle Module (KVM)
5. Engine Junction Box (EJB)
6. Starter motor
7. Ground
8. Power supply
9. Crankshaft Position (CKP) sensor

INPUT/OUTPUT DIAGRAM - SHEET 2 OF 2 - STARTING SYSTEM WITH AUTO STOP/START SYSTEM

A = HARDWIRED; AN = HIGH SPEED CONTROLLER AREA NETWORK (HS-CAN) POWERTRAIN SYSTEMS BUS; AO = MEDIUM SPEED CONTROLLER AREA NETWORK (MS-CAN) BODY SYSTEMS BUS; O = LOCAL INTERCONNECT NETWORK (LIN) BUS.

1. Engine Control Module (ECM)
2. Keyless Vehicle Module (KVM)
3. Central Junction Box (CJB)
4. Gateway Module (GWM)
5. Transmission control switch control module (equipped on vehicles with automatic transmissions only)
6. Instrument Cluster (IC)
7. Voltage Quality Module (VQM)
8. Starter relay
9. Starter motor
10. Ground
11. Power supply
12. Brake vacuum switch
13. Accelerator Pedal Position (APP) sensor
14. Ambient Air Temperature (AAT) sensor
15. Crankshaft Position (CKP) sensor
16. Neutral gear sensor
17. Clutch pedal position sensor
18. Brake pedal switch
19. Engine Coolant Temperature (ECT) sensor
20. Auto Stop/start switch
21. Hood switch
22. Stop/start switch

Stop / Start SwitchStarting System - Ingenium i4 2.0l Diesel / Diagnosis and Testing

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