1994 JAGUAR XJ6 electrical

3.2.2 ENGINE - GEARBOX/ TRANSMISSION
ASSEMBLY, RENEW
SRO 12.37.01/90
The engine /transmission unit on the V12 6.0 liter model is mounted on three engine mounting / bracket assemblies
fitted to the front crossmember on either side of the engine bay. The engine/ transmission rear mount is a mounting
bracket and spring assembly fitted and secured to body underframe longitudinal members. For access to remove the
engine carry
out the following procedures:
WARNING: WHEN WORKING WITHIN THE ENGINE COMPARTMENT, KEEP CLEAR OF THE RADIATOR COOLING
FANS AS THEY COULD START WITHOUT WARNING, EVEN IF THE ENGINE IS NOT RUNNING.
. Remove the hood, see SRO 76.16.01, section 13.
. Remove the two air cleaner assemblies, see SRO’s 19.10.01 & 19.10.02.
. Remove the engine cover, see SRO 12.29.93 (V12 Engine Service Manual).
Depressurize the fuel system, see SRO 19.50.02, section 5.1.
In line with the relevant SRO’s and sections, remove all appropriate obstructing parts, including their fixing and
. Disconnect all mechanical and isolate all electrical linkages leading to and from the engine.
. De-gas the air conditioning system, see section 14, Charge Recovery (System depressurization).
Disconnect
the battery.
mounting arrangements.
CAUTION: Do
not vent refrigerant directly to the atmosphere and always use Jaguar approved recovery/recycle/ra charge equipment.
Drain the engine oil, see 3.2.3 this section.
Drain the coolant, see SRO 26.10.01, section 4.1.
WARNING: DO NOT REMOVE THE HEADER TANK PRESSURE CAP WHILE THE ENGINE IS HOT. IF THE CAP MUST
BE REMOVED, PROTECT THE HANDS AGAINST ESCAPING STEAM AND SLOWLY TURN THE CAP ANTI- CLOCKWISE UNTIL THE EXCESS PRESSURE CAN ESCAPE. LEAVE THE CAP IN THIS POSITION UNTIL ALL
STEAM AND PRESSURE HAS ESCAPED AND THEN REMOVE THE CAP COMPLETELY.
Before
lifting the complete engine/transmission unit with an engine hoist from the engine bay, ensure that two engine
lifting brackets (tool 18G. 1465) are secured equallyspaced to the inlet manifold studs. The four engine lifting brackets
should be positioned towards the front and the rear of the assembly. Ensure the front of thevehicle is jacked
up secure- ly on stands when removing the assembly.
X300 VSM Issue 1 August 1994 2

Cooling System (AJl6) m
4.1.1 COOLING SYSTEM DESCRIPTION
4.1.1.1 Major Components
o Main engine crossflow radiator, incorporating a concentric tube cooler for the power steering fluid mounted in
the right
-hand radiator side tank. Vehicles with automatic transmission have a transmission fluid cooler
mounted in the left
-hand radiator side tank; for 4,O liter supercharged engines a six-plate cooler is fitted; other
vehicles have
a tube-type cooler. Adouble-action temperature switch, for controlling the radiator cooling fans,
is mounted in the left
-hand radiator side tank.
0 Two electrically operated radiator cooling fans, mounted behind the main radiator.
0 Coolant circulating pump, belt driven from the engine crankshaft.
0 Coolant header tank with pressure relief cap and coolant level probe.
o Engine thermostat.
4.1.1.2
0 Heater matrix.
o Electrically operated coolant circulating pump, mounted on the left-hand side of the engine bulkhead.
o Solenoid operated valve, located adjacent to the coolant circulating pump.
Components for Climate Control System
4.1.1.3 Components for Supercharged Engine
0 0 Supercharger crossflow radiator, mounted in front of the main radiator. The supercharger radiator is reverse- circuited, i.e. the coolant inlet is at the bottom of the radiator.
0 Electrically operated coolant circulating pump, located at the left-hand side of the main radiator.
4.1.1.4 Operation
The configuration of the cooling system for normally aspirated and supercharged (4,O liter) engines is shown in Sub- section 4.1.2.
The cooling system is pressurized, which allows the system to operate at a higher temperature without overheating.
The header tank is fitted with a pressure relief cap to protect the system against overpressure.
Under cold start conditions, coolant is forced by the engine driven water pump through the cylinder block and cylinder
head to the thermostat housing. The thermostat is closed to give rapid engine warm up, hence the coolant is returned
directly to the water pump inlet. When normal engine operating temperature is reached, the thermostat opens and
coolant is diverted through the radiator before returning to the water pump inlet. In vehicles fitted with
a supercharger,
coolant is circulated through the supercharger radiator and intercooler by the supercharger water pump. The super- charger cooling circuit uses the same coolant header tank as the main engine cooling system.
The radiator cooling fans operate in series and parallel under the control of the double
-action radiator mounted tem- perature switch. The fans are also controlled by the climate control system on vehicles fitted with air conditioning.
Under hot operating conditions, the fans may continue to operate after the engine has been switched off. The fans
stop automatically when the coolant temperature has been reduced sufficiently.
The system also provides the coolant supply for the climate control system, which is described in Section
14.
X300 VSM 1 Issue 1 August 1994

area washed to remove all traces of coolant.
CAUTION: To prevent the possibility of damage to the heater circuit pump and supercharger pump (where fitted),
the pumps should be electrically isolated if the ignition has to be turned ON while the cooling system is
drained.
WARNING: DO NOT REMOVE THE HEADER TANK PRESSURE CAP WHILE THE ENGINE IS HOT. IF THE CAP MUST
BE REMOVED, PROTECT THE HANDS AGAINST ESCAPING STEAM AND SLOWLY TURN THE CAP ANTI
- CLOCKWISE UNTIL THE EXCESS PRESSURE CAN ESCAPE. LEAVE THE CAP IN THIS POSITION UNTIL
ALL THE STEAM AND PRESSURE HAS ESCAPED AND THEN REMOVE THE CAP COMPLETELY.
WARNING: WHEN DRAINING THE COOLANT WITH THE ENGINE HOT, PROTECT THE HANDS AGAINST CONTACT
WITH HOT COOLANT.
WARNING: WHEN WORKING WITHIN THE ENGINE COMPARTMENT, KEEP CLEAR OF THE RADIATOR COOLING
FANS. THE FANS COULD START WITHOUT WARNING EVEN IF THE ENGINE IS NOT RUNNING.
4.1.3.2 Working Practices
Whenfilling thesystem with coolant,ensurethatthevehicle isstanding on a level surfaceandthatthecoolant is poured
in slowly so that airlocks are not introduced into the system. Airlocks can seriously affect the operation of the climate
control system and can cause damage to the heater circuit pump (and supercharger circuit pump if fitted).
Cooling System (AJ16)
4.1.3 SERVICE PROCEDURES
4.1.3.1 Safety Precautions
The anti-freeze specified in Appendix AI must be used wherever possible. It is designed to afford the maximum cor- rosion protection to all metals found in the engine cooling system, as well as having the frost protection properties
necessary during the winter months.
Should
it not be available, then anti-freeze conforming to Ford Motor Company specification ESLbM97B49-A may be
used. To provide optimum temperature and corrosion protection, the specified anti-freeze concentration must always
be used.
Once coolant has been drained from the system,
it must be discarded and not reused. Anti-freeze is harmful to the
environment. Used coolant must be disposed of safely and never poured down a drain connected to the public sewer.
CAUTION: Never fill or topup the system with water only.
CAUTION : Anti-freeze is harmful to paintwork. Coolant spillages must be wiped up immediately and the affected
Hose clips should always be positioned so that there is proper access for tightening and that the clip does not foul or
interfere with the operation of any components.
Drive belts must always be tensioned to the specified value and the tension checked
at the correct point on the belt.
This information is given in Subsection IV in the preliminary pages.
0
When tightening components, the torque figures given in Sukection II in the preliminary pages should always be
used for the fastenings listed.
4.1.3.3 Coolant Change
The coolant must be changed at intervals of four years. The system should be drained from the radiator drain plug,
flushed and filled with fresh coolant. Flushing should be carried out thoroughly to remove all the old coolant from the
engineand heater matrix. (The heatervalve isopen withthe ignition OFF). AfterfiIling,checkthecoolant concentration
with a hydrometer. For the specified anti-freeze and coolant concentration, see Appendix AI.
X300 VSM 3 Issue 1 August 1994

4.1.5 FAULT DIAGNOSIS
4.1.5.1 Introduction
The following diagnostic procedures are provided to assist properly qualified persons to identify and rectify the faults
in the system which are most likely to be encountered. Reference is made to the Electrical Diagnostic Manual (EDM),
which should be consulted for all electrical faults. When investigating faults relating to temperature, the prevailing
ambient temperature conditions should be taken into account. The climate control system is dealt with in Section 14.
Possible Cause
Thermostat stuck closed
Incorrect thermostat rating
Faulty temperature gauge
Faulty temperature transmitter
4.1.5.2 Diagnostic Procedures
Check
Test thermostat
Check thermostat operating
temperature
Refer to EDM
Refer to EDM
Symptom
herheating
Cooling fan(s) not operating 3verheating at
dle
roo cold
Refer to EDM
Incorrect thermostat rating
Thermostat not fitted
Cooling
fan(s) operating con-
tinuously Faulty temperature gauge
Faulty temperature transmitter
Radiator
core blocked
Radiator grille obstructed
Check thermostat operating
temperature
Remove thermostat housing
and inspect
Refer to EDM
Refer to EDM
Refer to EDM
Concentration of
anti
-freeze too high
Drive belt slack
Drive belt broken
Water pump seized
Insufficient coolant
Internally collapsed hoses
Incorrect ignition timing
Fuel
/ air mixture too weak
Incorrect valve
timing
Cylinder head gasket leaking
Brakes binding Check
for
hotspots in radiator
Check grille for obstruction
Check strength of coolant
Check belt tension
Visual check
Slacken drive belt and turn
water
pump pulley by hand.
Check belt for damage
Check coolant level
Pressure test system and
check for deformation of hoses
Refer to EDM
Refer to EDM
Check valve
timing
Pressure-test system. (Check
for contamination of coolant
in header tank)
Check brake calipers for stick
-
ing pistons and seized brake
pad pins
Thermostat stuck open
I Test thermostat
Remedy
Renew thermostat
Renew thermostat
Renew gauge
Renew transmitter
Flush
or renew radiator
Remove obstruction from
grille
Drain and fill
with coolant of
correct concentration
Adjust belt to correct tension
or renew belt
if worn
Renew belt
Renew water pump. Renew
drive belt
if required
Top-up coolant
Renew hoses as required
Rectify
as required
Rectify
as required
Correct valve
timing
Renew head gasket
Rectify
as required
Rectify
as required
Renew thermostat
Renew thermostat
Fit thermostat
Rectify
as required
Renew gauge
Renew transmitter
0
e
0
0
Issue 1 August 1994 X300 VSM

Cooling System (V12
4.2.1 COOLING SYSTEM DESCRIPTION I
4.2.1.1 Major Components
o Engine crossflow radiator, incorporating a concentric tube cooler for the power steering fluid mounted in the
left
-hand radiator side tank. Vehicles with automatic transmission have a six-plate transmission fluid cooler
mounted in the right
-hand radiator side tank. A double-action temperature switch, for controlling the electric
radiator cooling fans, is mounted in the left
-hand radiator side tank.
0 Engine driven, viscous-coupled, radiator cooling fan
0 Two electrically operated radiator cooling fans, mounted in front of the radiator.
o Coolant circulating pump, belt driven from the engine crankshaft.
0 Coolant header tank with pressure relief cap and coolant level probe.
0 Two engine thermostats, one in each cylinder bank.
4.2.1.2
0 Heater matrix.
0 Electrically operated coolant circulating pump, mounted on the left-hand side of the engine bulkhead.
o Solenoid operated valve, located adjacent to the coolant circulating pump.
Components for Climate Control System
1
4.2.1.3 Operation
The configuration of the cooling system is shown in Sub-section 4.2.2.
The cooling system is pressurized, which allows the system to operate at a higher temperature without overheating.
The header tank is fitted with a pressure relief cap to protect the system against overpressure.
Under cold start conditions, coolant is forced by the engine driven water pump through each cylinder block and cylin
- der head to the thermostat housings. The thermostats are closed to give rapid engine warm up, hence the coolant is
returned via the engine cross pipe to the water pump inlet. When normal engine operating temperature is reached,
the thermostats open and coolant is diverted through the radiator before returning to the water pump inlet.
If the engine driven fan is unable to provide sufficient cooling, the electrically operated fans operate in series and paral
-
lel underthe control of the radiator mounted temperature switch. Under hot operating conditions, the electric fans may
continue to operate after the engine has been switched off. The fans stop automatically when the coolant temperature
has been reduced sufficiently.
The system also provides the coolant supply for the climate control system, which is described in Section 14.
I
I X300 VSM 1 Issue 1 August 1994

WARNING: DO NOT REMOVE THE HEADER TANK PRESSURE CAP WHILE THE ENGINE IS HOT. IF THE CAP MUST
BE REMOVED, PROTECT THE HANDS AGAINST ESCAPING STEAM AND SLOWLY TURN THE CAP ANTI- CLOCKWISE UNTIL THE EXCESS PRESSURE CAN ESCAPE. LEAVE THE CAP IN THIS POSITION UNTIL
ALL THE STEAM AND PRESSURE HAS ESCAPED AND THEN REMOVE THE CAP COMPLETELY.
WARNING: WHEN DRAINING THE COOLANT WITH THE ENGINE HOT, PROTECT THE HANDS AGAINST CONTACT
WITH HOT COOLANT.
WARNING
: WHEN WORKING WITHIN THE ENGINE COMPARTMENT, KEEP CLEAR OF THE ENGINE DRIVEN RADI- ATOR COOLING FAN WHEN THE ENGINE IS RUNNING.
4.2.3.2 Working Practices
Whenfilling thesystem with coolant,ensurethatthevehicle isstanding on a level surfaceand thatthecoolant is poured
in slowly so that airlocks are not introduced into the system. Airlocks can seriously affect the operation of the climate
control system and can cause damage to the heater circuit pump.
Hose clips should always be positioned
so that there is proper access for tightening and that the clip does not foul or
interfere with the operation of any components.
4.2.3 SERVICE PROCEDURES
4.2.3.1 Safety Precautions
The anti-freeze specified in Appendix A1 must be used wherever possible. It is designed to afford the maximum cor- rosion protection to all metals found in the engine cooling system, as well as having the frost protection properties
necessary during the winter months. Should it not be available, then anti-freeze conforming to Ford Motor Company
specification
ESBM97B49-A may be used. To provide optimum temperature and corrosion protection, the specified
anti-freeze concentration must always be used. Once coolant has been drained from the system, it must be discarded
and not reused. Anti-freeze is harmful to the environment. Always dispose of used coolant safely and never pour it down a drain connected to the public sewer.
CAUTION: Never fill or topup the system with water only.
CAUTION
: Anti-freeze is harmful to paintwork. Coolant spillages must be wiped up immediately and the affected
area washed to remove all traces of coolant.
CAUTION: To prevent the possibility of damage to the heater circuit
pump, the pump should be electrically isolated if the ignition has to be turned ON while the cooling system is drained.
The drive belt must always be tensioned to the specified value and the tension checked at the correct point on the belt.
This information is given in Sub-section IV in the preliminary pages.
When tightening components, the torque figures given in Sub
-section II in the preliminary pages should always be
used for the fastenings listed.
When fitting a replacement thermostat, ensure that the jiggle-pin is to the top of the thermostat housing.
4.2.3.3 Coolant Change
The coolant must be changed at intervals of four years. The system should be drained from the radiator drain plug,
flushed and filled with fresh coolant. Flushing should be carried out thoroughly to remove all the old coolant from the
engine and heater matrix. (The heatervalve isopen with the ignition OFF). AfterfilIing,checkthecoolant concentration
with a hydrometer. For specified anti-freeze and coolant concentration, see in Appendix Al.
X300 VSM 3 Issue 1 August 1994

4.2.5.2 Diagnostic Procedures
1
I Symptom ..
Overheating
herheating at
dle
roo cold ~~~
Possible Cause
Thermostat(s) stuck
closed
Incorrect thermostat rating
Faulty temperature gauge
Faulty temperature transmitter
Radiator core blocked
Radiator grille obstructed
Concentration of anti
-freeze
too high
Drive belt slack
Drive belt broken
Water pump seized
lnsuff icient coolant
Internally collapsed hoses
Incorrect ignition timing
Fuel
/ air mixture too weak
Incorrect valve timing
Cylinder head
gasket(s) leak-
ing
Brakes binding
Electric cooling
fan(s) not op- erating
Thermostat(s) stuck open
Incorrect thermostat rating
Thermostatb) not fitted
Electric cooling
fan(s) operat-
ing continuously
Faulty temperature gauge
Faulty temperature transmitter
Check
Cooling System (V12)
4.2.5 FAULT DIAGNOSIS
4.2.5.1 Introduction
The following diagnostic procedures are provided to assist properly qualified persons to identify and rectify the faults in the system which are most likely to be encountered. Reference is made to the Electrical Diagnostic Manual (EDM), which should be consulted for all electrical faults. When investigating faults relating to temperature, the prevailing
ambient temperature conditions should be taken into account. The climate control system is dealt with in Section 14.
Test thermostat(s)
Check thermostat operating
temperature
Refer to EDM
Refer to EDM
Check for
hotspots in radiator
Check grille for obstruction
Check strength of coolant
Check belt tension
Visual check Slacken drive belt and turn
water pump pulley by hand.
Check belt for damage
Check coolant level
Pressure test system and
check for deformation of hoses
Refer to EDM
Refer to EDM
Check valve timing
Pressure
-test system. (Check
for contamination of coolant in
header tank)
Check brake calipers for stick
- ing pistons and seized brake
pad pins
..
Refer to EDM
Test
thermostat(4
Check thermostat operating
temperature
Remove thermostat housing
and inspect
Refer to EDM
Refer to EDM
Refer to EDM
Remedy
Renew thermostat(s)
Renew thermostat(s1
Renew gauge
Renew transmitter
Flush or renew radiator
Remove obstruction from
grille
Drain and
fill with coolant of
correct concentration
Adjust belt to correct tension
or renew belt
if worn
Renew belt
Renew water pump. Renew
drive belt
if required
Top
-up coolant
Renew hoses as required
Rectify as required
Rectify as required
Correct valve timing
Renew head
gasket(s)
Rectify as required
Rectify as required
Renew
thermostat(s1
Renew thermostatb)
Fit thermostat(s)
Rectify as required
Renew gauge
Renew transmitter
Issue 1 August 1994 X300 VSM 5

Automatic Transmission (AJ16)
Both types of automatic transmission comprise a hydrodynamic torque converter driving an epicyclic gear train which
provides four forward ratios and reverse. Gearshift selection is made by a hydraulic (or electronichydraulic) trans- mission control unit. Six gearshift positions are provided:
Position
'P' (Park) -the driven wheels are mechanically locked at the transmission.
Position
'R' (Reverse) - reverse gear selected.
Position
'N' (Neutral) - engine disconnected from drive-line and wheels.
Position 'D' (Drive)
- all four speed ranges are selected automatically with lock-up available in top gear only.
Position
'3' - automatic selection of the lowest three speed ranges only.
Position '2'
- automatic selection of the lowest two speed ranges only; the transmission is prevented from shift- ing up to the third and top speed ranges.
Immediate selection of a lower ratio is also available, within mapped limits, by 'kick
-down' (pressing the accelerator
pedal down beyond the normal full throttle position) for example when overtaking.
A brake pedal/gearshift interlock is incorporated in the shift lever mechanism. Theshift lever may only be movedfrom
the 'P' (Park) position if the ignition key switch is in position 'll', and the foot brake is applied. The ignition key cannot
be removed from the ignition switch unless the shift lever is in the 'P' (Park) position. Once the ignition key has been
removed, the shift lever is locked in the Park position. The gearshift interlock may be over-ridden manually in the event
of an electrical failure or when it is required to move the vehicle manually for access, ie for removal of the propeller
shaft.
8.1.1.1
Gearshift selection causes the appropriate gear to be selected through a cable operated shift lever on the side of the
Gear Selection (ZF 4HP 22)
transmission unit. When a gea; is selected, the shift points are determined by accelerator pedal position through a
throttle cable connection and by pressures equivalent to road speed derived from a centrifugal governor on the output
shaft.
Gearshift speed and quality are controlled by the hydraulic control unit located in the lower part of the transmission
housing. The control unit contains selector valve, control pistons and pressure valves.
The hydraulic control unit can be overridden by 'kickdown'. This is actuated by the final travel of the accelerator pedal
and causes the next lower gear to be selected.
8.1.1.2
Gearshift selection causes the appropriate gear to be selected through a cable operated shift lever on the side of the
transmission unit; the shift lever also operates a rotary switch attached to the side of the transmission unit. When a
gear is selected, the rotary switch provides an output or combination of outputs to the TCM, which continuously moni
- tors the gear selected in addition to output shaft speed and transmission oil temperature. Information from the Engine
Control Module (ECM) representing engine speed, load and throttle position is also fed to the TCM to enable the most
suitable gear to be selected.
Gear selection and gearshift speeds are controlled by the manually operated selector valve, a solenoid operated pres
- sure regulator and three solenoid valves. On receipt of signalsfrom the TCM, the three solenoid valves MVI, MV2 and
MV3, in various combinations with the safety valve, determine the appropriate gear range. The TCM, on receipt of
information of engine state and road speed, determines the shift speed.
The Performance Mode switch, located on the shift lever surround, provides two alternative shift speed patterns:
1. 'Normal (Economy) Mode' - designed for everyday use.
2. 'Sport Mode'
- gear shift takes place at higher road speeds to enhance performance.
The 'kick
-down' switch, located beneath the accelerator pedal, is actuated by the final travel of the pedal and signals
to the TCM that the next lower gear is to be selected.
Gear Selection (ZF 4 HP 24 E)
X300 VSM 3 Issue 1 August 1994