Range Rover 2. Electrical Manual - part 160

STARTING AND CHARGING

B1

8

TROUBLESHOOTING

Starter Solenoid
(K136) terminal
connection

Battery Terminal
Connection

Less than 0.5V

M134
Starter

Z238
Body Electrical
Control Module
(BECM)

OK

OK

PROBLEM CAUSE

OK

OK

2B

3A

1B

CONDITIONS

Ignition Switch

Position: 0

RESULTS

BAT VOLT

WR

CONDITIONS

Ignition Switch

Position: III

RESULTS

Wire

-

D

D

Test B

2A

PROBLEM CAUSE

Body Electrical Control
Module (BECM)

-

PROBLEM CAUSE

R Wire

-

-

C1282

V

WR

V

R

M

R

R

-

Ignition Switch

-

Wire

- WR

Wire

- B

STARTING AND CHARGING

B1

9

TROUBLESHOOTING

Z238
Body Electrical Control
Module (BECM)

BAT VOLT

OK

OK

PROBLEM CAUSE

OK

OK

2B

1C

CONDITIONS

Ignition Switch

Position: III

RESULTS

Less than 0.5V

B

CONDITIONS

Ignition Switch

Position: II

RESULTS

Wire

-

-

D

D

D

Engine running

Battery Terminal
Connection

Ground Connections

-

Test C

1B

PROBLEM CAUSE

Starter

-

- Starter Solenoid

PROBLEM CAUSE

NY Wire

-

PROBLEM CAUSE

Body Electrical
Control Module
(BECM)

-

V

C1289

V

B

B

NY

Instrument Cluster

-

CRUISE CONTROL

B5

CIRCUIT OPERATION

1

CIRCUIT OPERATION

Petrol Engine

For vehicles equipped with a manual transmission,
cruise control can only be activated when the Cruise
Control Switch (X115) is depressed, the transfer
gear box is in Hi range, and the clutch pedal is not
depressed. Also, the BeCM (Z238) will deactivate
cruise control if the engine rpm rises above 5000 

±

10%, due to the possibility of selecting gears
manually without the use of the clutch.

For vehicles equipped with an automatic
transmission, cruise control can only be activated
when the Cruise Control Switch (X115) is depressed,
the transfer gear box is in Hi range, and the
transmission is in one of the forward gears.

With the Cruise Control Switch (X115) on, a ground
signal is applied to C1279/Pin 14 of the BeCM
(Z238).The BeCM (Z238) then suplies signal voltage
via its Pin 18 to the Converter/Inverter (Z249), to Pin
8 of the Cruise Control ECU (Z121) and to the
“Operation” bulb of the Cruise Control Switch (X115).
The transfer gearbox Hi range status from the
Transfer Gear Box ECU (Z256) is applied to
C1287/Pin 3 of the BeCM (Z238). The X, Y, and Z
switch status (PRND321 position information) from
the gearbox position switch is applied to C1287/Pins
8, 9, and 18 of the BeCM (Z238). The clutch pedal
position input is applied to C1279/Pin 4 and the
engine speed input C1288/Pin 9 of the BeCM
(Z238). When the transfer gearbox is in Hi range, a
forward gear is selected and the Cruise Control
Switch (X115) is on, theBeCM (Z238) suplies voltage
via C1276/Pin 1 and the Brake Switch Vent Valve
(X112) to the Cruise Control ECU (Z121) Pin 1,
which then “knows” that cruise control can be
operated.

When cruise control is activated and a cruise speed
is set, the Cruise Control ECU (Z121) applies
voltage through the OU wire and ground through the
OR wire to operate the Cruise Control Vacuum
Pump (M103) motor. The Cruise Control ECU (Z121)
applies ground through the OK wire to close the
normally open solenoid valve in the pump. The pump
applies vacuum to the actuator.

SET/ACCEL

To set a cruise speed, the Cruise Control Switch
(X115) must be on and vehicle speed must exceed
28 mph (45 km/h). When the SET/ACCEL Switch is
depressed under these conditions, the

Converter/Inverter (Z249) is supplied with a ground
signal. This signal is “converted” to a voltage signal
and is transmitted via the SY wire to the Cruise
Control ECU (Z121) terminal 4, causing the vacuum
pump to operate. When the SET/ACCEL Switch is
released, the signal is removed from terminal 4,
signalling the ECU to set the speed.

RES/DECEL

When the RES/DECEL Switch is depressed, a signal
is applied via the RY wire to terminal 2 of the Cruise
Control ECU (Z121). This tells the ECU (Z121) to
disengage the system and the vehicle slows down.
When the switch is depressed a second time, the
signal is again applied to the ECU (Z121) and the
vehicle returns to the previously set speed.

Speed Input

Terminal 15 of the Cruise Control ECU (Z121)
receives the Vehicle Speed output signal from the
BeCM (Z238) through the Y or YR wire. The BeCM
(Z238) receives the vehicle speed signal from the
Anti–lock Brake System ECU (Z108). The signal is a
pulsing voltage and its frequency changes with
vehicle speed.