Range Rover 2. Electrical Manual - part 15

STARTING AND CHARGING

B1

7

TROUBLESHOOTING

Starter Solenoid
Relay

Engine Compartment
Fuse Box

P125a
Engine Compart-
ment Fuse Box

P125a
Engine Compart-
ment Fuse Box

BAT VOLT

Test A

OK

OK

OK

OK

3A

1A

2A

CONDITIONS

Ignition Switch

Position: III

RESULTS

BAT VOLT

CONDITIONS

Ignition Switch

Position: 0

RESULTS

D

D

2A

PROBLEM CAUSE

NR Wire

-

- Starter Solenoid

PROBLEM CAUSE

-

V

V

C508
C575

NR

WR

C177

-

STARTING AND CHARGING

B1

8

TROUBLESHOOTING

Starter Solenoid
(K136) terminal con-
nection

Battery Terminal Con-
nection

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 Mod-
ule (BECM)

-

PROBLEM CAUSE

R Wire

-

-

C113

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 Con-
nection

Ground Connections

-

Test C

1B

PROBLEM CAUSE

Starter

-

- Starter Solenoid

PROBLEM CAUSE

NY Wire

-

PROBLEM CAUSE

Body Electrical Con-
trol Module (BECM)

-

V

C114

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 C255/Pin 14 of the BeCM
(Z238).The BeCM (Z238) then suplies signal voltage
via its Pin 18 to the Converter/Inverter (Z249), to Pin
10 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
C626/Pin 3 of the BeCM (Z238). The X, Y, and Z
switch status (PRND321 position information) from
the gearbox position switch is applied to C626/Pins
8, 9, and 18 of the BeCM (Z238). The clutch pedal
position input is applied to C255/Pin 4 and the
engine speed input C112/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
C258/Pin 1 and the Brake Switch Vent Valve (X112)
to the Cruise Control ECU (Z121) Pin 9, 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 3, causing the vacuum
pump to operate. When the SET/ACCEL Switch is
released, the signal is removed from terminal 3,
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 4 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 11 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.