Land Rover Freelander 2002my Electrical Library 3rd Edition Rover Manual

							DESCRIPTION AND OPERATION
4.70FREELANDER 02MY
Torque Converter Lock-Up
When the gearbox is in 4th or 5th gear, and the ATCU registers a high vehicle speed 
combined with a small throttle angle, the ATCU will lock the torque converter. This will 
enable maximum power to be transmitted to the road wheels. When this occurs, the ATCU 
(C0932) provides a PWM signal to the Lock-Up solenoid (C0243) on a U wire. The solenoid 
(C0243) is earthed via the ATCU (C0932) on an SB wire. For more details on torque 
converter lock-up, refer to the   Automatic Gearbox – Jatco   section of the System 
Description and Operation Workshop manual.
Shift Interlock
When the ignition switch is in the ignition position and the selector lever is in the Park, the 
ATCU (C0932) provides a feed to the shift interlock solenoid (C0268) on a GW wire locking 
the selector lever in the Park position. When the brake pedal is pressed, the brake pedal 
switch (C0652) provides a feed to the ATCU (C0932) on a GR wire. Sensing the brake pedal 
has been pressed the ATCU withdraws the feed to the shift interlock solenoid, releasing the 
selector lever.
The shift interlock solenoid (C0268) is earthed on a B wire.
Diagnostic Socket
If the ATCU detects a failure in an associated component, a fault code will be stored in its 
memory. TestBook or T4 can be used via the diagnostic socket to retrieve these fault codes 
to identify the cause of the failure. The diagnostic socket (C0040) is connected to the ATCU 
(C0932) by a K wire. 
						

							DESCRIPTION AND OPERATION
FREELANDER 02MY 4.71
ANTI-LOCK BRAKING SYSTEM (ABS) – 01MY
DESCRIPTION
General
The ABS is a full time, four channel system that gives individual speed control to all four 
wheels to provide the vehicle with anti-lock braking (ABS), Electronic Traction Control 
(ETC), and Hill Descent Control (HDC). The systems are controlled by the ABS ECU, which 
is mounted on the rear of the ABS modulator. The ABS ECU also controls the front to rear 
brake balance by Electronic Braking force Distribution (EBD). This maximises vehicle 
stability under braking.
For a detailed description of ABS, ETC HDC, and EBD, refer to the  Brakes  section of the 
System Description and Operation Workshop manual.
The ABS modulator uses the CAN-BUS to communicate with other ECUs to enable it to 
control braking more efficiently. For more information on the CAN-BUS, refer to the  
Communication Databuses  section of the Workshop manual. 
						

							DESCRIPTION AND OPERATION
4.72FREELANDER 02MY
OPERATION
General
Feed from the positive battery terminal (C0192) is supplied to fusible link 1, fusible link 3, 
fusible link 8, and fusible 11 (C0632) on an R wire. All are located in the engine compartment 
fuse box.
Fusible link 8 (C0574) and fusible link 11 (C0570) provide constant battery feeds to the ABS 
modulator (C0500) on NK and NR wires respectively. The ABS modulator (C0500) is 
earthed on a pair of B wires.
Fusible link 1 is connected in series with fusible link 2, which is also located in the engine 
compartment fuse box. Fusible link 2 (C0571) provides a feed to the ignition switch (C0028) 
on an NR wire. Fusible link 3 (C0571) also provides a feed to the ignition switch (C0028) on 
an N wire.
When the ignition switch is turned to the ignition position, current flows across the switch 
(C0028) to fuse 2 of the passenger compartment fuse box (C0588) on an NW wire. When in 
the ignition position, the ignition switch (C0028) also provides a feed to fuse 7 and fuse 35 
of the passenger compartment fuse box on a G wire.
Fuse 2 of the passenger compartment fuse box (C0580) provides an ignition feed to the 
brake pedal switch (C0075) and the HDC relay (C0574) on G wires. Fuse 35 (C0580) 
provides an ignition feed to the brake pedal sensor (C0652) on a W wire, and fuse 7 (C0582) 
provides an ignition feed to the ABS ECU (C0500), also on a W wire.
Wheel Speed Sensors
The ABS ECU (C0500) supplies a feed to all four wheel speed sensors as follows:

To the LH front wheel speed sensor (C0516) on a G wire.

To the RH front wheel speed sensor (C0517) on a G wire.

To the LH rear wheel speed sensor (C0502) on a W wire.

To the RH rear wheel speed sensor (C0503) on a W wire.
The wheel speed sensors provide the ABS ECU with a square wave form signal. By 
measuring the frequency of the wave form, the ABS ECU can calculate the speed of the road 
wheel. The sensors provide the ABS ECU (C0500) with wheel speed signals as follows:

From the LH front wheel speed sensor (C0516) on a G wire.

From the RH front wheel speed sensor (C0517) on a G wire.

From the LH rear wheel speed sensor (C0502) on a W wire.

From the RH rear wheel speed sensor (C0503) on a W wire.
If the ABS ECU detects wheel deceleration is too great, it will initiate the ABS. If the ABS 
ECU detects that wheel speed is greater than vehicle speed, it will initiate ETC. If HDC is 
operational, the ABS ECU will control vehicle speed at 7 mph (11 km/h) by applying the 
brakes where necessary. For more information on ABS, ETC, and HDC, refer to the  Brakes  
section of the System Description and Operation Workshop manual. 
						

							DESCRIPTION AND OPERATION
FREELANDER 02MY 4.73
ABS ECU
Td4 (Manual Transmission)
The ABS ECU (C0500) provides a road wheel speed signal to the Engine Control Module 
(ECM) (C0331) via the CAN BUS on YN (low) and YB (high) wires.
Td4 (Automatic Transmission)
The ABS ECU (C0500) provides a road wheel speed signal to the Automatic Transmission 
Control Unit (ATCU) (C0932) via the CAN BUS on YN (low) and YB (high) wires.
K1.8
The ABS ECU (C0500) provides a road wheel speed signal to the Engine Control Module 
(ECM) (C0913) via the CAN BUS on YN (low) and YB (high) wires.
KV6
The ABS ECU (C0500) provides a road wheel speed signal to the ATCU (C0932) via the 
CAN BUS on YN (low) and YB (high) wires. This information is relayed to the ECM (C0371) 
via the CAN BUS on YN (low) and YB (high) wires.
For more information on the CAN BUS, refer to the  Communication Databuses  section 
of the System Description and Operation Workshop manual.
Brake Pedal Sensor
The brake pedal sensor is a Hall effect sensor, located at the top of the brake pedal. The 
sensor (C0652) is provided an ignition feed from fuse 35 of the passenger compartment fuse 
box (C0580) on a W wire. The sensor (C0652) is earthed on a B wire.
When the brake pedal is pressed, the brake pedal sensor (C0652) provides a feed to the 
following components:

To the Engine Control Module (ECM) (C0331) on a PG wire (Td4 vehicles only).

To the ECM (C0331) on a GR wire (Td4 vehicles only).

To the Automatic Transmission Control Unit (ATCU) (C0932) on a GR wire (automatic 
transmission vehicles only).

To the Cruise control ECU (C0239) on a PG wire (KV6 vehicles only).

To the cruise control interface unit (C0895) on a PG wire (KV6 vehicles only).

To the cruise control interface unit (C0895) on a GR wire (KV6 vehicles only).
For more information on the Jatco automatic transmission, refer to the  Electronic 
Automatic Transmission (EAT) – 01MY  section of this manual.
 
+  ELECTRONIC AUTOMATIC TRANSMISSION (EAT) – 01MY. 
For more information on KV6 cruise control operation, refer to the  Cruise Control – KV6  
section of this manual.
 
+  CRUISE CONTROL – KV6.  
						

							DESCRIPTION AND OPERATION
4.74FREELANDER 02MY
Brake Pedal Switch
The brake pedal switch is a double contact mechanical switch, mounted at the top of the 
brake pedal adjacent the brake pedal sensor. The switch (C0075) is provided an ignition 
feed from fuse 2 of the passenger compartment fuse box (C0580) on a G wire. When the 
brake pedal is at rest, the switch (C0075) provides a feed to the ABS ECU (C0500) on a GR 
wire. When the brake pedal is pressed, the switch (C0075) informs the ABS ECU (C0500) 
by providing a feed on a GP wire.
When the brake pedal is pressed, the switch (C0075) also provides a feed to the following 
on GP wires:

The LH brake lamp (C0121).

The RH brake lamp (C0125).

The Centre High Mounted Stop Lamp (CHMSL) (C0613).
For more information on brake lamp operation, refer to the  Brake and Reverse Lamps  
section of this manual.
 
+  BRAKE AND REVERSE LAMPS. 
Accelerometer
The accelerometer is mounted beneath the centre console adjacent the handbrake, and 
provides the ABS ECU additional information regarding vehicle motion. The ABS ECU 
(C0500) provides a feed to the accelerometer (C1220) on a Y wire. The sensor (C1220) 
returns a vehicle acceleration/deceleration signal to the ABS ECU (C0500 on 01MY 
vehicles, C0501 on 02MY vehicles) on an R wire.
The accelerometer (C1220) is provided an earth path via the ABS ECU (C0500 on 01MY 
vehicles, C0501 on 02MY vehicles) on a U wire. 
Brake Fluid Level Switch
The ABS ECU (C0500) provides a feed to the brake fluid level switch (C0026) on a BW wire. 
The switch is closed when the correct amount of brake fluid is present in the brake fluid 
reservoir. The switch (C0026) is earthed on a B wire. If the brake fluid level drops below the 
recommended level, the switch contacts open. When the ABS ECU registers the switch 
opening, it informs the instrument pack to illuminate the brake fluid warning lamp via the 
CAN-BUS. 
For more information on warning lamp operation, refer to the  Instruments  section of this 
manual.
 
+  INSTRUMENTS.  
						

							DESCRIPTION AND OPERATION
FREELANDER 02MY 4.75
Hill Descent Control (HDC)
HDC Relay
The HDC relay (C0575) is located in the engine compartment fuse box, and is provided a 
feed by the ABS ECU (C0500) on a BR wire. Operation of the HDC relay is controlled by the 
ABS ECU via the HDC switch (C0365 on manual vehicles, C0878 on automatic vehicles) on 
a W wire (see below).
When energised, the HDC relay (C0570) provides a feed to the following on GP wires:

The ABS ECU (C0500).

The LH brake lamp (C0121).

The RH brake lamp (C0125).

The CHMSL (C0613).
HDC Switch (Manual Transmission)
The HDC switch (C0365) is mounted on the gear lever, and informs the ABS ECU (C0500) 
when HDC has been selected. When HDC is selected, the switch contacts close, and a feed 
is provided to the ABS ECU on a PS wire.
HDC Switch (Automatic Transmission)
The HDC switch (C0878) is mounted on the centre console, and informs the ABS ECU 
(C0500) when HDC has been selected. When HDC is selected, the switch contacts close, 
and a feed is provided to the ABS ECU (C0500) on a PS wire.
NOTE: The ABS ECU will only initiate HDC if either 1st or reverse gear are selected, and 
brake temperature doesnt exceed 400 
°C (752 °F).
For more information on HDC, refer to the  Brakes  section of the System Description and 
Operation Workshop manual.
Diagnostic Socket
The diagnostic socket (C0040) is connected to the ABS ECU (C0500) by a K wire, enabling 
the ABS ECU to be interrogated by TestBook or T4. 
						

							DESCRIPTION AND OPERATION
4.76FREELANDER 02MY
ANTI-LOCK BRAKING SYSTEM (ABS) – 02MY
DESCRIPTION
General
The ABS is a full time, four channel system that gives individual speed control to all four 
wheels to provide the vehicle with anti-lock braking (ABS), Electronic Traction Control 
(ETC), and Hill Descent Control (HDC). The systems are controlled by the ABS ECU, which 
is mounted on the rear of the ABS modulator. The ABS ECU also controls the front to rear 
brake balance by Electronic Braking force Distribution (EBD). This maximises vehicle 
stability under braking.
For a detailed description of ABS, ETC HDC, and EBD, refer to the  Brakes  section of the 
System Description and Operation Workshop manual.
The ABS modulator uses the CAN-BUS to communicate with other ECUs to enable it to 
control braking more efficiently. For more information on the CAN-BUS, refer to the  
Communication Databuses  section of the System Description and Operation Workshop 
manual.
OPERATION
General
Feed from the positive battery terminal (C0192) is supplied to fusible link 1, fusible link 3, 
fusible link 8, and fusible 11 (C0632) on an R wire. All are located in the engine compartment 
fuse box.
Fusible link 8 (C0574) and fusible link 11 (C0570) provide constant battery feeds to the ABS 
modulator (C0501) on NK and NR wires respectively. The ABS modulator (C0501) is 
earthed on a pair of B wires.
Fusible link 1 is connected in series with fusible link 2, which is also located in the engine 
compartment fuse box. Fusible link 2 (C0571) provides a feed to the ignition switch (C0028) 
on an NR wire. Fusible link 3 (C0571) also provides a feed to the ignition switch (C0028) on 
an N wire.
When the ignition switch is turned to the ignition position, current flows across the switch 
(C0028) to fuse 2 of the passenger compartment fuse box (C0588) on an NW wire. When in 
the ignition position, the ignition switch (C0028) also provides a feed to fuse 7 and fuse 35 
of the passenger compartment fuse box on a G wire.
Fuse 2 of the passenger compartment fuse box (C0580) provides an ignition feed to the 
brake pedal switch (C0075) and the HDC relay (C0574) on G wires. Fuse 35 (C0580) 
provides an ignition feed to the hill descent switch (C0365 on manual transmission vehicles, 
C0878 on automatic transmission vehicles), and the hill descent relay (C0571) on W wires. 
Fuse 7 (C0582) provides an ignition feed to the ABS ECU (C0501) on a W wire. 
						

							DESCRIPTION AND OPERATION
FREELANDER 02MY 4.77
Wheel Speed Sensors
The ABS ECU (C0501) supplies a feed to all four wheel speed sensors as follows:

To the LH front wheel speed sensor (C0516) on an R wire.

To the RH front wheel speed sensor (C0517) on a Y wire.

To the LH rear wheel speed sensor (C0502) on a G wire.

To the RH rear wheel speed sensor (C0503) on a W wire.
The wheel speed sensors provide the ABS ECU with a square wave form signal. By 
measuring the frequency of the wave form, the ABS ECU can calculate the speed of the road 
wheel. The sensors provide the ABS ECU (C0501) with wheel speed signals as follows:

From the LH front wheel speed sensor (C0516) on an RB wire.

From the RH front wheel speed sensor (C0517) on a YB wire.

From the LH rear wheel speed sensor (C0502) on a GB wire.

From the RH rear wheel speed sensor (C0503) on a WB wire.
If the ABS ECU detects wheel deceleration is too great, it will initiate the ABS. If the ABS 
ECU detects that wheel speed is greater than vehicle speed, it will initiate ETC. If HDC is 
operational, the ABS ECU will control vehicle speed at 7 mph (11 km/h) by applying the 
brakes where necessary. For more information on ABS, ETC, and HDC, refer to the  Brakes  
section of the System Description and Operation Workshop manual.
ABS ECU
Td4 – Manual Transmission
The ABS ECU (C0501) provides a road wheel speed signal to the Engine Control Module 
(ECM) (C0331) via the CAN BUS on YN (low) and YB (high) wires.
Td4 – Automatic Transmission
The ABS ECU (C0501) provides a road wheel speed signal to the Automatic Transmission 
Control Unit (ATCU) (C0932) via the CAN BUS on YN (low) and YB (high) wires.
K1.8
The ABS ECU (C0501) provides a road wheel speed signal to the Engine Control Module 
(ECM) (C0913) via the CAN BUS on YN (low) and YB (high) wires.
KV6 – NAS
The ABS ECU (C0502) provides a road speed signal to the ATCU (C0932) via the CAN BUS 
on YN (low) and YB (high) wires. This information is relayed to the ECM (C0331) via the CAN 
BUS on YN (low) and YB (high) wires. 
						

							DESCRIPTION AND OPERATION
4.78FREELANDER 02MY
KV6 – ROW
The ABS ECU (C0500 on 01MY vehicles, C0501 on 02MY vehicles) provides a road wheel 
speed signal to the ATCU (C0932) via the CAN BUS on YN (low) and YB (high) wires. This 
information is relayed to the ECM (C0371) via the CAN BUS on YN (low) and YB (high) 
wires.
For more information on the CAN BUS, refer to the  Communication Databuses  section 
of the System Description and Operation Workshop manual.
Brake Pedal Switch
The brake pedal switch is a double contact mechanical switch, mounted at the top of the 
brake pedal adjacent the brake pedal sensor. The switch (C0075) is provided an ignition 
feed from fuse 2 of the passenger compartment fuse box (C0580) on a G wire. When the 
brake pedal is at rest, the switch (C0075) provides a feed to the ABS ECU (C0501) on a GR 
wire. When the brake pedal is pressed, the switch (C0075) informs the ABS ECU (C0501) 
by providing a feed on a GP wire.
When the brake pedal is pressed, the switch (C0075) also provides a feed to the following 
on GP wires:

The LH brake lamp (C0121).

The RH brake lamp (C0125).

The Centre High Mounted Stop Lamp (CHMSL) (C0613).
For more information on brake lamp operation, refer to the  Brake and Reverse Lamps  
section of this manual.
 
+  BRAKE AND REVERSE LAMPS. 
Accelerometer
The accelerometer is mounted beneath the centre console adjacent the handbrake, and 
provides the ABS ECU additional information regarding vehicle motion. The ABS ECU 
(C0501) provides a feed to the accelerometer (C1220) on a Y wire. The sensor (C1220) 
returns a vehicle acceleration/deceleration signal to the ABS ECU (C0501) on an R wire.
The accelerometer (C1220) is provided an earth path via the ABS ECU (C0501) on a U wire. 
Brake Fluid Level Switch
The ABS ECU (C0501) provides a feed to the brake fluid level switch (C0026) on a BW wire. 
The switch is closed when the correct amount of brake fluid is present in the brake fluid 
reservoir. The switch (C0026) is earthed on a B wire. If the brake fluid level drops below the 
recommended level, the switch contacts open. When the ABS ECU registers the switch 
opening, it informs the instrument pack to illuminate the brake fluid warning lamp via the 
CAN-BUS. 
For more information on warning lamp operation, refer to the  Instruments  section of this 
manual.
 
+  INSTRUMENTS.  
						

							DESCRIPTION AND OPERATION
FREELANDER 02MY 4.79
Hill Descent Control (HDC)
HDC Switch (Manual Transmission)
The HDC switch (C0365) is mounted on the gear lever, and informs the ABS ECU (C0501) 
when HDC has been selected. When HDC is selected, the switch contacts close, and a feed 
is provided to the ABS ECU (C0501) on a PS wire. When the ABS ECU receives this feed, 
it energises the HDC relay.
HDC Switch (Automatic Transmission)
The HDC switch (C0878) is mounted on the centre console, and informs the ABS ECU 
(C0501) when HDC has been selected. When HDC is selected, the switch contacts close, 
and a feed is provided to the ABS ECU (C0501) on a PS wire. When the ABS ECU receives 
this feed, it energises the HDC relay.
NOTE: The ABS ECU will only initiate HDC if either 1st or reverse gear are selected, and 
brake temperature doesnt exceed 400 
°C (752 °F).
HDC Relay
The HDC relay (C0575) is located in the engine compartment fuse box, and is controlled by 
the ABS ECU (C0501) on a BR wire. When energised, the HDC relay (C0570) provides a 
feed to the following on GP wires:

The ABS ECU (C0500 on 01MY vehicles, C0501 on 02MY vehicles).

The LH brake lamp (C0121).

The RH brake lamp (C0125).

The CHMSL (C0613).
Diagnostic Socket
The diagnostic socket (C0040) is connected to the ABS ECU (C0501) by a K wire, enabling 
the ABS ECU to be interrogated by TestBook or T4.