Content .. 86 87 88 89 ..

Range Rover. Manual - part 88

LAND ROVER V8

DESCRIPTION AND OPERATION

ECM pin details for Connector C505 continued:

Pin No.

Description

Input/Output

Voltage

S sensor Upstream - Heater supply

Output

Heater

resistance =

5.7 ohms

Malfunction Indicator Lamp (MIL)

Output drive

Switch to

ground

Engine speed output

Output

12V square

wave (4 pulses

per revolution)

Fuel pump relay

Output drive

Switch to

ground

Not used

Throttle position

Analogue input

0 - 5V (1.4V at

idle)

S sensor Upstream - Heater supply

Output

Heater

resistance =

5.7 ohms

Engine torque

Output

12V PWM

Injector - Cylinder 4

Output

0 - 12V

Not used

Injector - Cylinder 7

Output

0 - 12V

Injector - Cylinder 5

Output

0 - 12V

IACV-C Stepper motor

Output

stepped by

sequentially

changing

voltage polarity

IACV-A Stepper motor

Output

stepped by

sequentially

changing

voltage polarity

Injector - Cylinder 2

Output

0 - 12V

FUEL SYSTEM

NEW RANGE ROVER

DESCRIPTION AND OPERATION

Crankshaft position (CKP) sensor - (up to 99MY)

The crankshaft position sensor is the most important
sensor on the engine. It is located in the left hand side
of the flywheel housing and uses a different thickness
of spacer for manual and automatic gearboxes. The
signal it produces informs the ECM:
- the engine is turning
- how fast the engine is turning
- which stage the engine is at in the cycle

As there is no default strategy, failure of the CKP
sensor will result in the engine failing to start. The fault
is indicated by illumination of the malfunction indicator
light (MIL) on North American specification vehicles.

The output signal from the CKP sensor is obtained
from the magnetic path being made and broken as the
reluctor ring teeth pass the sensor tip. The reluctor
ring has 35 teeth and one missing tooth spaced at
10

intervals. The missing tooth is positioned at

after TDC.

Fault codes:

•

P0335 -Crankshaft sensor circuit fault - no signal

•

P0336 -Crankshaft sensor generating poor
quality signal

Camshaft position (CMP) sensor - (up to 99MY)

The camshaft sensor is located in the engine front
cover, between the belt pulleys. It is a Hall Effect
device which produces four pulses for every two
revolutions of the engine. The signal is used for two
purposes, injector timing corrections for fully
sequential fuelling and active knock control. The CMP
sensor signal pulses are generated from four gaps on
the cam wheel, one gap is smaller than the other
three, consequently one of the pulses is longer than
the others.

If the camshaft sensor fails, default operation is to
continue normal ignition timing. The fuel injectors will
be actuated sequentially, timing the injection with
respect to top dead centre. Injection will either be
correct or one revolution out of synchronisation. The
fault is not easily detected by the driver. The fault is
indicated by illumination of the malfunction indicator
light (MIL) on North American specification vehicles.

Fault codes:

•

P0340 - Camshaft sensor circuit fault or signal
timing different from crankshaft sensor signal.

NOTE: It is physically possible to
interchange the camshaft gear wheel fitted
to pre-99MY and post-99MY vehicles.

However, because the GEMS and Motronic
systems are incompatible, an incorrect camshaft
signal will be received by the ECM and a P0340
fault code will result.

LAND ROVER V8

DESCRIPTION AND OPERATION

Mass air flow (MAF) sensor - (up to 99MY)

The ’hot wire’ type mass air flow sensor is mounted
rigidly to the air filter and is connected by flexible hose
to the plenum chamber inlet. The MAF sensor is a hot
wire anenometer. The main sensing element of the
sensor is a heated wire, positioned in the stream of
intake air. Changes in intake air flow changes the
temperature, and hence resistance, of the wire. The
ECM measures this change in resistance and
calculates the amount of air flowing into the engine.

As there is no default strategy, failure will result in the
engine starting, and dying when it reaches 550
rev/min, when the ECM detects no MAF sensor
signal. The fault is indicated by illumination of the
malfunction indicator light (MIL) on North American
specification vehicles.

Intake Air Temperature (IAT) sensor - (up to 99MY)

The IAT sensor is another resistive sensor, located in
the body of the air cleaner. The sensor resistance
varies with changes in air temperature. The signal
from the IAT sensor is used to retard the ignition
timing if the air temperature rises above 55

C. If the

sensor is disconnected or failure occurs, a default
value will be used by the system. The default value
selected will represent nominal operating conditions.
The fault may not be evident to the driver, there may
be slight power loss in high ambient temperatures.
The fault is indicated by illumination of the malfunction
indicator light (MIL) on North American specification
vehicles.

Throttle Position (TP) sensor - (up to 99MY)

The throttle position sensor is mounted on the throttle
body in line with the throttle plate shaft. The sensor is
a variable resistor, the signal from which (0 - 5V)
informs the ECM of the actual position of the throttle
disc and the rate of change of throttle position. This
information is used by the ECM for regulation of
acceleration enrichment fuelling. Sensor failure will
adversely affect the acceleration performance. The
closed throttle voltage is continuously monitored and
updated when engine conditions indicate that the
throttle is closed.

The GEMS ECM performs a throttle potentiometer
range check by cross checking with the measured air
flow. If the two values do not correlate and fuelling
feedback indicates that fuelling and therefore airflow is
correct, the potentiometer is assumed to have failed.
In the event that a fault is detected, GEMS supplies a
default value dependent on air flow.

The throttle angle is also supplied to the gearbox
ECM, the loss of this signal will result in poor gear
change quality and loss of kickdown.

WARNING: If the throttle potentiometer is
changed, it is necessary to reset the
closed throttle voltage.

Fault codes:

•

P0121 - Throttle potentiometer signal
inconsistent with MAF, IACV, air temperature
and engine rpm.

•

P0122 - Throttle potentiometer circuit low input

•

P0123 - Throttle potentiometer circuit high input

FUEL SYSTEM

NEW RANGE ROVER

DESCRIPTION AND OPERATION

Engine Coolant Temperature (ECT) sensor - (up to
99MY)

The sensor is located at the top front of the engine, to
the right of the alternator and in front of the plenum
chamber.

The sensor comprises a temperature dependant
resistive metal strip. The resistance of the strip varies
considerably with coolant temperature, i.e. from 28K
ohms at - 30

C to 90 ohms at 130

C. At 85

C the

resistance is 300 ohms. The ECT sensor signal is vital
to engine running, as the correct fuelling is dependant
upon engine temperature i.e. richer mixture at low
temperatures.

If the sensor is disconnected or failure occurs, a
default value will be supplied to the system. The initial
default value selected will be based on the value of
the air intake temperature. This will increase to a
nominal warmed up value over a given time,
programmed for each default value. The fault may not
be evident to the driver, there may be a hot restart
problem. The fault is indicated by illumination of the
malfunction indicator light (MIL) on North American
specification vehicles.

Fault codes:

•

P0116 - Coolant temperature sensor - falling
temperature fault

•

P0117 - Coolant temperature sensor circuit low
range fault

•

P0118 - Coolant temperature sensor circuit high
range fault

•

P0125 - Coolant temperature sensor - no
warm-up fault

Engine Fuel Temperature (EFT) sensor - (up to
99MY)

The EFT sensor is located on the fuel rail by cylinders
3 and 5. The sensor measures the temperature of the
rail rather than the fuel. The resistance varies with
changes in temperature. The signal is used to
increase the injection pulse time when undergoing hot
restarts. When the fuel is hot, vapourisation can occur
in the fuel rail and bubbles form in the injectors.
Increasing the pulse time helps flush the fuel vapour
away. An EFT sensor fault may not be evident to the
driver, there may be a hot restart problem. The fault is
indicated by illumination of the malfunction indicator
light (MIL) on North American specification vehicles.

Fault codes:

•

P0181 - Fuel temperature sensor fault - reading
invalid compared with water temperature

•

P0182 - Fuel temperature sensor circuit low
range fault

•

P0183 - Fuel temperature sensor circuit high
range fault

Content .. 86 87 88 89 ..