Land Rover Lesson 2 Auto Trans Coolingine Rover Manual

							Fault DescriptionComponent/SignalP Code
Signal voltage too smallEPRS 6P276200
Short circuit to power supplyEPRS 6P276300
Short circuit to groundEPRS 6P276400
CONTROLLER AREA NETWORK
(CAN)
The high speed CAN broadcast bus network is used to
connect the powertrain modules. The CAN bus is
connected between the following electronic units:
High Speed CAN Bus
•TCM
•Instrument cluster
•Air suspension module
•Steering angle sensor
•Rear differential module
•Centre console switch pack
•Electric park brake module
•Restraints control module
•Engine Control Module (ECM)
•ABS control module
•Adaptive front lighting control module
•Transfer box control module
•Adaptive cruise control module
•Diagnostic socket.
The CAN bus allows a fast exchange of data between
modules. The CAN bus comprises two wires which are
identified as CAN high (H) and CAN low (L). The two
wires are coloured yellow/black (H) and yellow/brown
(L) and are twisted together to minimise electromagnetic
interference (noise) produced by the CAN bus messages.
In the event of CAN bus failure, the following symptoms
may be observed:
•Transmission operates in default mode
•Torque converter lock-up clutch control is disabled
•Gear position indication in instrument cluster
message centre inoperative (this will also occur with
any transmission fault).
DRIVING MODES
There are a number of different driving modes of
operation. Some can be selected by the driver and some
are automatically initiated by the TCM during driving:
•Normal mode
•Sport mode
•Manual (CommandShift™) mode
•Adaptive Shift Strategy (ASIS)
•Hill Descent Control (HDC) mode
•Cruise mode
•Hill mode
•Default (Limp home) mode
•Reverse lock-out mode
•Cooling strategy.
•Curve recognition mode
•Fast off recognition
Normal Mode
Normal mode is automatically selected by the TCM on
power up. In this mode all automatic and adaptive modes
are active. Normal mode uses gear shift and lock-up
maps to allow for vehicle operation which offers fuel
consumption and emissions or driveability depending
on the driving style. If the transmission is operated in
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							sport or manual mode and the selector lever is moved
to the D position, normal mode is automatically
resumed.
Sport Mode
The sport mode operates in high range only and provides
enhanced acceleration and responsiveness. In sport mode
the TCM uses shift maps which allow the transmission
to downshift more readily, hold gears for longer at
higher engine speeds, and limits the transmission to the
first five gears (6th gear is not used).
Sport mode is selected by moving the selector lever to
the left into the M/S position. When the sport mode is
first selected, SPORT is displayed in the message centre
for 6 seconds and, if 6th gear is currently engaged, the
TCM downshifts to 5th.
Manual (CommandShift™) Mode
Manual mode allows the transmission to operate as a
semi-automatic CommandShift™ unit. The driver can
change up and down the six forward gears with the
freedom of a manual transmission.
Shift maps are provided for manual mode to protect the
engine at high engine speeds. The TCM will
automatically change up to a higher gear ratio to prevent
engine overspeed and change down to a lower gear ratio
to avoid engine labouring and stalling.
When kickdown is requested the TCM downshifts at
least 2 gears.
When the vehicle is stationary, to drive off the driver
can select 1st , 2nd or 3rd gear in low and high range.
Any other gear selection will be rejected by the TCM.
When driving off, upshifts can be pre-selected by
making + selections with the selector lever for the
number of upshifts required. The TCM then
automatically performs a corresponding number of
upshifts when the appropriate shift points are reached.
So, for example, when starting off in 1st gear, if three
+ selections are made in quick succession, the TCM
will automatically change up through the box to 4th
gear as the vehicle accelerates, without any further
selections being made.
In manual mode a low gear can be selected to provide
engine braking for descending a slope without HDC or
continuous use of the brake pedal. The driver can
prepare for the end of the descent by moving the selector
lever to D. The TCM will maintain the low gear and
only revert to automatic shift control when the throttle
is opened and vehicle speed increases.
Adaptive Shift Strategy (ASIS)
The ASIS system is a new feature on automatic
transmissions. With the TCM linked via the CAN bus
to other vehicle systems, signals are received which can
allow the TCM to calculate the way in which the vehicle
is being driven. The type of signals include the
following:
•Longitudinal and lateral acceleration
•Engine speed
•Engine torque
•Oil temperature
•Accelerator pedal position
•Wheel speed.
Using these signals, additional transmission control can
be obtained. The TCM can calculate when the vehicle
is cornering, all wheels are gripping, the driver is
braking or if the driver is accelerating. This is the
conventional Adaptive transmission control. ASIS uses
this system but adds the continuous adaptation of the
gear changes to the individual driving style of the driver.
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							HDC Mode
The HDC mode assists the ABS module in controlling
the downhill speed of the vehicle. When HDC is selected
on, the ABS module selects the most appropriate gear
for the descent, to maximise engine braking.
Cruise Mode
When speed control is activated, the TCM receives a
cruise active message on the CAN bus. The TCM
activates a speed control map which prevents locking
and unlocking of the torque converter clutch and
minimises up and down shifts.
Hill Mode
Hill mode is initiated by the TCM when the engine
torque, via ECM signals on the CAN bus, exceeds the
theoretical load curve for normal operation. The TCM
monitors this signal to determine when the vehicle is
travelling up or down a steep gradient.
In hill mode the TCM adopts one of four shift maps,
three uphill and one downhill. The shift map chosen
depends on the severity of the slope as determined from
the engine signals and the appropriate gear is selected
to assist with the ascent or descent.
Hill mode can also be initiated when the vehicle is at
very high altitudes or ambient temperatures, and also
when the vehicle is towing.
Default (Limp Home) Mode
If a transmission fault is detected by the TCM, the TCM
adopts a limp home mode strategy. TRANS.
FAILSAFE is displayed in the message centre and, if
the fault has an effect on engine emissions, the MIL will
also be illuminated.
In default mode, P, R and N functions operate normally
(if the fault allows these selections) and the TCM locks
the transmission in 3rd or 5th gear to allow the driver
to take the vehicle to the nearest dealer. The torque
converter lock-up clutch is disabled and reverse lock-out
will not function.
If the vehicle is stopped and subsequently restarted in
the default mode condition, the TCM operates normally
until the fault which caused the condition is detected
again.
When limp home mode is active, the gear position
indicator will show one of the following letters which
defines the fault type:
•F - transmission is operating in limp home mode
•H - transmission has reached overheat threshold
temperature and transmission is operating in limp
home mode
•E - CAN bus is off and transmission is operating in
limp home mode.
If electrical power is lost and the transmission is
operating in mechanical limp home mode, the selector
lever will not be locked in the N position by the shift
interlock solenoid. The lever will be locked in the P
position and can only be released by using the interlock
emergency release lever or by correcting the electrical
fault.
Reverse Lock-Out Mode
When the vehicle is travelling forwards, selecting
reverse could cause transmission damage. To protect
against this, reverse gear is prohibited if the vehicle is
travelling forwards at a road speed above 5 mph (8
km/h).
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							Cooling Strategy
The purpose of the cooling strategy is to reduce engine
and transmission temperatures during high load
conditions, when towing a trailer for example. Under
these conditions the engine and transmission may
generate excessive heat.
If the transmission fluid temperature increases to 125ºC
(257ºF) or higher, the TCM employs the cooling
strategy. The message TRANSMISSION OVERHEAT
is displayed in the message center.
The strategy uses a specific shift and torque converter
lock-up clutch map. This map allows torque converter
clutch lock-up and gear shifts to operate outside of their
normal operation. This will reduce the engine speed
and/or slip in the torque converter, therefore reducing
heat generated by the engine and the transmission.
If the transmission fluid temperature increases to 137ºC
(278ºF) or higher, the transmission will use the default
(limp home mode). H is displayed in the gear position
indicator. If the temperature exceeds 140ºC (284ºF),
CAN bus transmission is disabled and E is displayed
in the gear position indicator.
The cooling strategy is cancelled when the transmission
fluid temperature decreases to less than 120ºC (248ºF)
or below.
Curve Recognition
Curve recognition is activated when high levels of lateral
acceleration and/or steering angle are detected via the
ABS module and steering angle sensor signals on the
CAN bus. When this condition is detected, the TCM
prevents the transmission from changing to a higher
gear to assist with cornering. When the vehicle
completes it manoeuvre, the transmission will shift to
the correct ratio.
Fast Off Recognition
Fast off recognition is activated when the TCM detects
that the driver has backed off the accelerator pedal
quickly in a change of mind manoeuvre. This is
detected by monitoring for a high level of negative pedal
angle from the engine control module signal on the CAN
bus. If this condition is detected, the TCM holds the
current gear ratio to allow the driver to complete his
original action without the need for a downshift. The
mode remains active for a predetermined time period
or if the driving style remains passive.
Terrain Response™ Mode
If the vehicle has the Terrain Response system fitted,
the following additional modes are available.
Grass/Gravel/Snow
When the driver selects the Terrain Response
grass/gravel/snow special program with the transfer box
in either high or low range, the TCM uses a specific set
of shift and torque converter maps to optimise the
delivery of torque to the wheels and to minimise wheel
slip in these terrains. To assist with the vehicle moving
from a standstill, the TCM automatically selects 2nd
gear in high range and 3rd gear in low range. This
special program is fully integrated with hill mode to
enhance vehicle control during ascents and descents.
Mud/Ruts
When the driver selects the Terrain Response mud/ruts
special program with the transfer box in either high or
low range, the TCM uses a specific set of shift and
torque converter maps to optimise vehicle traction in
this terrain.
Sand
When the driver selects the Terrain Response sand
special program with the transfer box in either high or
low range, the TCM uses a specific set of shift and
torque converter maps to optimise the tractive
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							performance in sand by holding onto gears longer and
downshifting more readily. This mode is fully integrated
with the hill mode to further enhance performance
during ascents.
Rock Crawl
When the driver selects the Terrain Response rock crawl
special program, which is only available with the
transfer box in low range, the TCM uses a specific shift
map which maximises torque delivery at slow speeds
associated with this type of terrain.
TRANSMISSION FAULT STATUS
If the TCM detects a fault with the transmission system,
it will enter a default mode to prevent further damage
to the transmission and allow the vehicle to be driven.
When a fault is detected a CAN message is sent from
the TCM and is received by the instrument cluster. The
instrument cluster illuminates the MIL and displays
TRANS. FAILSAFE in the message centre.
Some transmission faults may not illuminate the MIL
or display a fault message, but the driver may notice a
reduction in shift quality.
ENGINE SPEED AND TORQUE
MONITORING
The ECM constantly supplies the TCM with information
on engine speed and torque through messages on the
CAN bus. The TCM uses this information to calculate
the correct and appropriate timing of shift changes.
If the messages are not received by the ECM, the TCM
will implement a back-up strategy to protect the
transmission from damage and allow the vehicle to be
driven.
In the event of an engine speed or torque signal failure,
the transmission will adopt the electrical limp home
mode with the transmission operating in a fixed gear.
TOWING FOR RECOVERY
The following procedure must be used to ensure that
the vehicle is towed in a safe condition and damage to
the vehicle transmission systems is prevented.
–Secure the towing attachment from the recovery
vehicle to the towing eye of the vehicle to be
recovered.
–Make sure that the hand brake is on. Turn the ignition
key to the ignition position II.
–Apply the footbrake and move the automatic
transmission selector lever to the neutral position. If
electrical power is not available, use the manual
interlock release tab on the selector lever to move
the lever to the neutral position.
–Make sure that the ignition is in the auxiliary position
I or, if the stop lamps and turn signal indicators are
required, in the ignition position II.
–Make sure that the hand brake is released before the
vehicle is towed.
–The vehicle can only be towed for a maximum of 31
miles (50 km) at a maximum speed of 30 mph (50
km/h). Towing the vehicle for longer distances and/or
faster speeds will damage the transmission.
WARNING: Do not remove the key or move
the ignition switch to position O when the
vehicle is being towed. The steering lock will be
engaged preventing the steering from being
turned.
With the engine not running, the brake booster and
power steering pump will be inoperative. Care must
be taken to ensure the vehicle is manoeuvred and
driven accordingly.
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							CONTROL DIAGRAM
NOTE: A = Hardwired;  D= High Speed CAN Bus
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							Diagnostic socket1
Mechatronic Valve (including TCM, sensors and
solenoids)
2
Instrument cluster3
Engine Control Module (ECM)4
Selector indicator5
Selector indicator6
Fusible link 7E (50A)7
Fuse 43P (5A)8
Selector lever assembly9
Fuse 33P (5A)10
Ignition switch11
Fusible link 10E (30A)12
Fuse 27P (5A) – Ignition feed13
Fuse 4E (10A) – Permanent feed14
Starter relay15
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							New Product Introduction
2005.0 Discovery 3
Description and Operation
Technical Training en 05/2004 
						

							To the best of our knowledge, the illustrations, technical information, data and descriptions in this issue were correct at the time
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							PAGE
Lesson 1 – General Information
Lesson 2 – Powertrain
13Objectives....................................................................................................................................................
16Engine..........................................................................................................................................................
16GENERAL......................................................................................................................................................................
17Technical  Features..........................................................................................................................................................
17Engine  Data.....................................................................................................................................................................
18CYLINDER BLOCK COMPONENTS..........................................................................................................................
26CRANKSHAFT, SUMP AND OIL PUMP COMPONENTS........................................................................................
34CAMSHAFT  TIMING  COMPONENTS.......................................................................................................................
36CYLINDER  HEAD  COMPONENTS............................................................................................................................
46LUBRICATION  SYSTEM.............................................................................................................................................
48EXHAUST  MANIFOLD................................................................................................................................................
49Engine..........................................................................................................................................................
49GENERAL......................................................................................................................................................................
50TECHNICAL  FEATURES.............................................................................................................................................
51ENGINE DATA..............................................................................................................................................................
52CYLINDER BLOCK COMPONENTS..........................................................................................................................
61CRANKSHAFT  AND  SUMP  COMPONENTS............................................................................................................
67CAMSHAFT  TIMING  COMPONENTS.......................................................................................................................
69CYLINDER  HEAD  COMPONENTS............................................................................................................................
73VARIABLE VALVE TIMING (VVT)...........................................................................................................................
76LUBRICATION  SYSTEM.............................................................................................................................................
80EXHAUST  MANIFOLD................................................................................................................................................
Table of Contents
3Technical Training