Land Rover Discovery Ii Valeo Bcu Ecu Manual

							 
 
 
The heart of the Discovery series 2 The Valeo BCU has been custom produced for this application and 
takes care of nearly everything not catered for by independent systems. There are actually different 
versions with slightly different capabilities and functionality, however this is handled totally 
transparently and cleverly with capability that has been built in that allows settings to be crossed from 
one ECU version to another. 
 
 
 
 
Vehicle makes models and variants known or believed to be using this vehicle system, required 
diagnostic lead and degree of known compatibility. 
 
Vehicle Make Vehicle Model Vehicle Variant Diagnostic Lead Compatibility level 
Land Rover Discovery II ALL Blue OBD Lead Verified 
Land Rover Discovery II ALL Green OBD Lead Verified 
 
 
 
 
 
 
    
 
 
 
 
 
 VALEO BCU (DISCO II) - Diagnostic Capabilities (Read Inputs) 
 
VALEO BCU (DISCO II) - System Overview 
 
VALEO BCU (DISCO II) - Known Fitments  
						

							 
Real time live display of the information the electronic control unit of the selected vehicle 
system is currently deriving from its input sensors. 
BODY 1 
 
LIGHTS 
 Sidelights: The sidelights input are used by the BCU to give, amongst other things a 
lights left on warning sound. 
 Main beam: When the lighting switch is moved to the flash or main position, the feed 
from fusible link 10 in the engine compartment fuse box passes through the switch 
contacts. The feed is connected to the passenger compartment fuse box, where it passes 
through fuses 3 and 22. The IDM senses the headlamp main beam request and through 
internal circuitry, provides a feed to the main beam warning lamp in the instrument pack. 
 Dipped: When the lighting switch is moved to the headlamp position, the feed from 
fusible link 10 in the engine compartment fuse box passes through the switch contacts. 
The feed is to the passenger compartment fuse box, where it passes through fuses 9 and 
10. 
 Front fog light: When the front fog lamp switch is operated, an earth path is completed 
from the BCU to the switch. The completion of the earth path signals the BCU to provide 
an earth path from the coil of the front fog lamp relay in the engine compartment fuse 
box to the BCU. The energized coil closes the contacts in the front fog lamp relay. 
 Rear fog light: When the front fog lamp switch is operated, an earth path is completed 
from the BCU to the switch. The completion of the earth path signals the BCU to provide 
an earth path from the coil of the front fog lamp relay in the engine compartment fuse 
box to the BCU. The energized coil closes the contacts in the front fog lamp relay. 
 Left/right hand indicator: The BCU supplies a reference voltage from for the LH 
flasher and for the RH flasher. When the flasher switch is moved to the LH or RH hand 
flasher position an earth path is completed. The completion of the earth, signals the BCU 
that a request for LH or RH flasher operation has been made. The BCU then sends a 
signal to the IDM in the passenger compartment fuse box. The signal is received by the 
IDM and interpreted as a request for LH or RH flasher operation. The IDM grants an 
earth path for the coil of the LH or RH direction indicator relay. The IDM controls the 
flasher operation by momentarily removing and restoring the earth for the relay coil, 
which opens and closes the contacts causing the indicator bulbs to flash on and off. The 
resistor is used by the IDM to monitor the current drawn through the resistor by the 
direction indicator bulbs. If an indicator bulb fails, the IDM detects the drop in current 
draw across the resistor and operates the flasher relay at a faster speed. The faster flash is 
also transmitted to the instrument pack to inform the driver of the bulb failure. 
 
 Hazards: The BCU supplies a reference voltage to the hazard warning switch. When the 
hazard warning switch is operated an earth path is completed from the switch. The 
completion of the earth signals the BCU that a request for hazard warning lamp operation  
						

							has been made. The BCU then sends a signal to the IDM in the passenger compartment 
fuse box. The signal is received by the IDM and interpreted as a request for hazard 
warning lamp operation. The IDM grants an earth path for the coils of the LH and RH 
direction indicator relays. The IDM controls the flasher operation by momentarily 
removing and restoring the earth for the relay coils, which opens and closes the contacts 
causing the indicator bulbs to flash on and off. The resistor is used by the IDM to monitor 
the current drawn through the resistor by the direction indicator bulbs. If an indicator 
bulb fails, the IDM detects the drop in current draw across the resistor and operates the 
flasher relay at a faster speed. The faster flash is also transmitted to the instrument pack 
to inform the driver of the bulb failure. 
 Daytime run light: The feed from fuse 13 in the engine compartment fuse box is 
connected to the coil of the daylight running relay and the IDM integral with the 
passenger compartment fuse box. When the engine is started, the IDM senses, through 
internal circuitry, that the engine is running and provides an earth for the daylight running 
relay coil. The energized coil closes the contacts of the daylight running relay allowing 
the feed from fuse 5 in the passenger compartment fuse box to pass through the relay 
contacts. 
DOORS 
 Passenger/Driver door switch: When a door is opened the BCU provides earth paths 
from the interior lamps, the load space lamp and the ignition switch illumination through 
the BCU. 
 Bonnet: 
 Key lock/unlock: The BCU uses the drivers door key lock and unlock switches to 
activate and deactivate the security system. The drivers door lock is also used for 
entering the EKA code. Two separate switches are incorporated into the key lock 
assembly of the drivers door. The switches are normally open and the BCU provides a 
separate power supply to each. The BCU is signaled when a circuit is earthed enabling it 
to determine the direction in which the lock has been turned. 
 CDL lock/unlock: The CDL switch is connected on a KR wire to BCU. This connection 
provides an earth input to the BCU to signal that the lock has been requested from the 
CDL switch. A second connection from the CDL switch on a YK wire to BCU provides 
an earth input to the BCU to signal that unlock has been requested from the CDL switch. 
 Inertia: The permanent battery feed is connected from fuse 13 in the engine 
compartment fuse box to the inertia switch. From the inertia switch the feed is connected 
back to the engine compartment fuse box. From the fuse box the feed is connected to the 
passenger compartment fuse box where it is then connected to the IDM. From the IDM 
the feed is connected on the BCU. When the inertia switch is operated, the battery feed to 
the IDM is removed. This is sensed by the BCU, which automatically unlocks the doors, 
only if the ignition is in position II and the alarm is disarmed. 
 
 Ignition Key inserted: The status of the ignition key in ignition barrel switch.  
						

							 Transfer box neutral: This is the supply voltage as measured by the BCU at its 
transistor switching circuit stages located within the BCU itself. 
 Park/neutral: 
BODY 2 
TRANSMISSION 
 Reverse idle: The status of the reverse switch input. When reverse gear is selected, a feed 
from fuse 25 in the passenger compartment fuse box is connected on a GY wire to the 
reverse lamp switch (manual transmission) or the starter inhibitor/reverse lamp switch 
(automatic transmission). 
 Transfer neutral switch: 
 Autobox W switch: The status of the Automatic gearbox currently selected gear W 
switch. 
 Autobox X switch: The status of the Automatic gearbox currently selected gear X 
switch. 
 Autobox Y switch: The status of the Automatic gearbox currently selected gear Y 
switch. 
 Autobox Z switch: The status of the Automatic gearbox currently selected gear Z switch. 
 Park neutral switch: This displays whether the Autobox is in Park or Neutral 
WINDOWS 
 Front Left/right hand window up: The window switch up contact is connected 
to the BCU by a BS wire. When the switch is set to the up position an internal 
supply from the BCU flows along the BS wire through the contacts of the switch 
and to earth via earth header. The motor is energized and drives the window 
mechanism towards the up position. 
 Front Left/right hand window down: The window switch down contact is 
connected to the BCU by a BR wire. When the switch is set to the down position 
an internal supply from the BCU flows along the BU wire through the contacts of 
the switch and to earth via earth header. The motor is energized and drives the 
window mechanism towards the down position. 
WASH WIPE 
 Front intermit: Operation of the front screen wash/wipe switch to the intermittent 
position allows a feed from fuse 19 to pass to the wash/wipe switch. The BCU 
interprets the signal as an intermittent wiper request and signals the IDM via the serial 
data bus. 
 
  
						

							 Front wash: When the switch stalk is pulled, a feed passes through the washer switch 
contacts and is connected, from the switch, to the washer pump and the BCU. If  the 
washer switch is held for longer than 0.4 seconds the BCU signals the IDM through 
the serial data bus to energies the front wiper relay. The IDM energizes the front 
wiper relay for 4 seconds allowing the screen to be cleared. After 4 seconds the IDM 
removes the earth path for the relay coil, causing the wipers to return to the park 
position. 
 Front wiper parked: The status of the front wiper as determined by the IDM. 
 Front wiper speed: 
 Rear wiper: When the rear wiper switch is operated an earth path is completed 
through the switch contacts and header, to earth. The completed earth path provides a 
signal to the BCU that rear wiper operation has been requested. The BCU sends a 
signal through the serial data bus to the IDM to commence wiper operation. The IDM 
provides a power supply and earth for the coil of the rear wiper relay in the passenger 
compartment fuse box, which energizes closing the relay contacts. 
 Rear wash: When the rear screen washer switch is operated, a feed from fuse 30 in 
the passenger compartment fuse box is connected to the switch. The pump operates 
for as long as the switch is pushed. The connection to the BCU signals that rear 
washer operation has been requested. The BCU signals the IDM to energies the rear 
wiper relay to operate the rear wiper 0.5 seconds after the request has been made. 
HEATED SCREEN 
 Heated screen switch: The HRW is operated from a non-latching switch located to 
the left of the instrument pack. The switch has an indicator light to show when the 
HRW is operating. The HRW element comprises fourteen metallic strips bonded to 
the inside surface of the rear window. The HRW will only function when the engine 
is running due to the high current draw and subsequent load on the battery. The HRW 
can also be operated by the air temperature control ECU on vehicles fitted with air 
conditioning. When the HRW is selected on, heater elements in the door mirror glass 
also operate. 
 Ignition 2: The status of the ignition stage 2 input. 
 Engine speed signal: This is an internal status within the BCU. 
 
INSTRUMENT 
 Left/right hand DI: 
 Left trailer indicator: The feed for the trailer connection is taken from header C0289, 
via header C0295, on a GR wire to the trailer pick-up. The trailer pick-up is connected on 
a B wire to earth eyelet connector C0808-1. 
 Right trailer indicator: The feed for the trailer connection is taken from header C0289, 
via header C0723, on a GW wire to the trailer pick-up. The trailer pick-up is connected 
on a B wire to earth eyelet connector C0808-1. 
  
						

							 Seat belt: The seat belt switch is connected to the BCU on a RW wire. The seat belt 
switch is earthed on a B wire. 
 Diff lock: When the differential lock unit switch is operated, an earth path is completed 
from the SLABS ECU to the differential lock unit switch. 
 Transfer neutral: The status of the Transfer in neutral input to the BCU. The 
transmission neutral sensor provides an earth signal to the BCU when the transfer box is 
in neutral. The earth signal causes the BCU to operate an audible warning to warn of the 
transfer box in neutral when the ignition is on. 
 Autobox manual: The manual warning lamp is connected to the EAT ECU. 
 Autobox sport: The sport warning lamp is connected to the Electronic Automatic 
Transmission (EAT) ECU. 
 Off road level: The off road warning lamp is connected to the instrument pack to the off 
road mode switch. 
 ABS: The ABS warning lamp is connected from the instrument pack to the SLABS ECU. 
 Traction control: The traction control warning lamp is connected from the instrument 
pack to the SLABS ECU. 
 SRS: The SRS warning lamp is connected from the instrument pack, to fuse 35 in the 
passenger compartment fuse box. Another connection to the SRS warning lamp is 
connected from the instrument pack to the airbag ECU. 
 HDC select: The HDC active warning lamp is connected from the instrument pack to the 
SLABS ECU. 
 Glow plug: The glow plug warning lamp is connected on the instrument pack to the 
ECM on a BY wire. 
 Brake: The handbrake and low brake fluid level warning lamps are connected to the 
instrument pack to the handbrake switch, the handbrake switch is locally earthed. A 
second connection connected to the brake fluid level switch on a KO wire. If either of the 
switches closes, an earth circuit via the closed switch contacts is completed and the 
handbrake/low fluid level warning lamp will be illuminated. 
 Oil pressure: The oil pressure warning lamp is connected to the instrument pack to the 
oil pressure warning switch, the oil pressure warning switch is locally earthed. If the oil 
pressure switch closes, an earth circuit via the closed switch contacts is completed and 
the oil pressure warning lamp will be illuminated. 
 Alternator: 
 Check engine: 
 Fuel filter: Fuel filter warning lamp (TD5 models only). A water sensor is installed in the 
fuel system, the power supply for the sensor is from fuse 10 in the engine compartment 
fuse box and the closed contacts of the fuel pump relay on a WP wire. The operation of 
the fuel pump relay coil is controlled by the Engine Control Module (ECM). When the 
water in the filter becomes too great, the instrument pack illuminates the warning lamp 
when the voltage reaches a predetermined level. 
 Transmission temp.: This shows the state of the transmission oil temperature overheat 
input. The sensors are located in the gearbox oil cooler and the rear of the transfer 
gearbox. 
  
						

							 Check ACE: The ACE warning lamp is connected from the instrument pack to the ACE 
ECU. 
 Check HDC: The hill descent fail warning lamp is connected from the instrument pack 
to the SLABS ECU. 
 Check SLS: The SLS warning lamp is connected from the instrument pack to the SLABS 
ECU. The drivers door closed input is enabled by the SLABS ECU to illuminate the SLS 
warning lamp in some remote control operating modes. 
 Instr. mileage (km): This is an input which is internal to the instrument pack. 
 BCU mileage (km): This is an input which is internal to the instrument pack. 
 IP Trip switch: This is an input which is internal to the instrument pack. 
POWER DISTRIBUTION 
 BCU Ignition pos.1: The status of the ignition stage 1 input. 
 BCU Ignition pos.2: The status of the ignition stage 2 input. 
 BCU Ignition pos.3: The status of the ignition stage 3 input. Whilst measuring this input 
you may require external power or to disconnect the starter motor. 
 IP Ignition pos.2: 
 IDM ignition pos.2: The ignition stage 2 status at the Intelligent Drivers Module located 
within the passenger compartment fuse box. 
 IDM battery (V): This is the supply voltage as measured by the Intelligent Drivers 
Module located within the Dash mounted fuse box. 
 BCU switch power: This is the supply voltage as measured by the BCU at its transistor 
switching circuit stages located within the BCU itself. 
 BCU relay power: This is the supply voltage as measured by the BCU at the internal 
relays located within the BCU itself. 
 
 
 
Values, configuration settings, and other stored information which can be read from the ECU, 
edited and then rewritten back. Read settings can also be stored as a standard HTML page for 
reference. These pages can then later be re loaded and re written back to the ECU. Please note 
that some values may be read only due to the fact that they are supplied from the ECU’s ROM or 
are internally calculated. 
 
IMPORTANT NOTICE. 
 A LOCKED BCU CANNOT BE UNLOCKED BY DIAGNOSTIC METHODS AND IF LOCKED THE VIN CANNOT 
BE WRITTEN USING THE NANOCOM OR OTHER DIAGNOSTICS 
 
 
 
BCU (Discovery II) - Diagnostic Capabilities (Settings)  
						

							 
LIGHTS WINDOWS - SEATS 
 Front fog lamp: The options are: 
 The vehicle is not fitted with front fog lamps (NONE). 
 The front fog lamps operate when the headlamps are dipped or are on main beam 
(MAIN). 
 The front fog lamps will not operate if the headlamps are on main beam (NO MAIN). 
 Daytime run lights: Legislation in some markets requires that the headlamps illuminate   
whilst the vehicle is moving, or the ignition is switched on. This function is referred to as 
daylight running lamps. Therefore, the BCU, which controls illumination of the 
headlamps, must also be programmed to accommodate the legislative requirements of 
individual markets, with regard to daylight running lamps. The options are: 
 The vehicle does not require the daylight running lamp feature to operate in any 
circumstance (NONE). 
 The daylight running lamps will be on if the main beam head lamps are off (NO MAIN). 
 The daylight running lamps will be on whenever the main or dipped beam head lamps 
are switched  off and the gear selector lever is in any position other than  park (NO 
HEADS). 
 Courtesy headlamps: The BCU can be programmed to turn on the vehicle headlamps 
when the driver presses the remote transmitter. The BCU switches both headlamps on by 
signaling to IDM to switch the headlamp relay ON. 
 Headlamp power wash: This option is used if headlamp power washers are fitted to the 
vehicle. 
 Electric Front window: The BCU can be programmed to disable operation of the front 
windows to conform to differing market legislative requirements. Available options are: 
 The front windows will be disabled 44 seconds after the driver door is opened (DRIVER 
CANCEL). 
 The front windows will not be disabled (NO CANCEL). 
 The front windows will be disabled when the ignition is turned off (ALL CANCEL). 
 Rear windows sunroof: Although the rear windows and sunroof are controlled by a 
hard-wired circuit, the rear windows and sunroof ECU are enabled by the BCU. This 
allows programming of the BCU to disable these outputs to conform to differing market 
legislative requirements. Available options are: 
 The rear windows and sunroof will be disabled 44 seconds after the driver door is 
opened (DRIVER). 
 The rear windows and sunroof will be disabled 44 seconds after any door is opened (NO 
CANCEL). 
 The rear windows and sunroof will be disabled when the ignition is turned off (ALL 
CANCEL). 
  
						

							 
 Heated front screen: Sets whether the Heated Front screen is Fitted or Not Fitted 
 Electric front seats: This setting is used to configure the operation of the electric front 
seats available options are: 
 The vehicle is not fitted with electric front seats (NOT FITTED). 
 The electric seats are available if the ignition is on or the driver door is opened for a 
short time (FITTED). 
 The electric seats are available if the ignition is on (IGNITION II). 
 Programmed wash wipe: The front wash switch is located on the wiper stalk, the rear 
wash switch is located in the instrument pack surround. They are both momentary 
switches (do not stay in when released). The way the vehicle reacts to the driver pressing 
the front or rear windscreen wash switch depends upon this setting programmed within 
the BCU. There are two options: 
 No wiper operation when the wash switch is pressed (NO WIPE). 
 Wiper action after an initial delay of 400mS (WIPE). 
 Seat belt warning: This setting controls operation of the seat belt warning lamp to suit 
legislative market requirements. Available options are: 
 Timed - The warning lamp is on for 6 seconds after ignition warning lamp is turned on 
 Buckle - 
 Ignition II - 
 Disabled - The warning lamp is not used 
 Driver Door - 
 Ignition or Crank - If the buckle is unfastened when the ignition is turned on then the 
lamp is on for 6 seconds 
 Fastened - The warning lamp is on for 6 seconds after ignition is turned on or until the 
buckle is fastened 
 
 Seat belt warning sound: This setting controls operation of the seat belt warning 
sounder to suit legislative market requirements. Available options are: 
 Timed - 
 Buckle - 
 Ignition II - 
 Disabled - The warning sound is not used 
 Driver Door - 
 Ignition or Crank - 
 Fastened – 
 
 
 
 
  
						

							 
 Autographics: The BCU can be programmed to change the situations in which the 
automatic gearbox selector leaver illumination (AUTOGRAPHICS) is enabled. The 
automatic gearbox selector illumination can be on whenever the ignition is on (ALWAYS 
option) or it can be on when the ignition is on and the sidelights are on (SIDELIGHTS 
option). 
TRANSM-LOCK-WARN 
 
 Transmission: Configure the BCU for either Automatic or Manual. 
 Shift interlock: Certain market legislations require that an vehicle must be in neutral or 
park before removal of the ignition key is allowed, the BCU therefore, is able to be 
programmed to control solenoids for this purpose. Available options are: 
 The vehicle is not fitted with a shift interlock solenoid (NONE). 
 The vehicle is fitted with both shift interlock and transfer box interlock solenoids 
(SHIFT). 
 The vehicle is fitted with a shift interlock but no transfer box interlock solenoid (NO 
TRANSF). 
 HDC: Fitted or Not Fitted. 
 Super lock: Super locking prevents the use of the interior door handles to unlock and 
open the vehicle doors. This prevents an intruder gaining access to the vehicle by 
smashing a window to open a door. Pressing the remote transmitter or turning the key in 
the door lock activates super locking. The market specification and customer 
configuration options will determine if super locking will activate and how it can be set. 
There are four options: 
 No super locking (DISABLE). 
 Pressing the lock button on the remote transmitter once (NO KEY). 
 Pressing the lock button on the remote transmitter, or turning the key once 
(SINGLE). 
 Pressing the lock button on the remote transmitter, or turning the key twice within 
1 second (DOUBLE). 
The vehicle needs to be in the correct state before super locking will activate. 
These conditions are: 
 All doors closed. 
 Ignition key not inserted in ignition switch. 
 Inertia switch not tripped.