1999 JAGUAR S TYPE sensor

V8 Engine AJ-V6/AJ28
54
Engine Management Sensors
The configuration of the AJ28 engine management sensors is changed from the previous V8 variants:
¥ New components unique to AJ28 engine are the MAF sensor and engine fuel temperature (EFT)
sensor.
¥ Components in common with the V6 engine are the IAT sensor, KS sensors, injector pressure (IP)
sensor, engine oil temperature (EOT) sensor and HO2 sensors.
¥ The crankshaft (CKP) and camshaft (CMP) sensors are the same as those fitted to the AJ27 engine.
Heated Oxygen (HO2) Sensors
Upstream and dowmstream HO2 sensors are
fitted and are of the type used on the V6 engine
(the linear type sensor is not used).
J.303.1387
HO2 SENSORS
J.303.1387
J.303.1281
COIL ON PLUG UNIT
J.303.1281
Ignition System
The coil-on-plug ignition modules are specific to
the AJ28 engine and are triggered directly from
the PCM. Double electrode platinum plugs are
fitted.

V8 EngineAJ-V6/AJ28
55
J.303.1389
ENGINE MANAGEMENT SCHEMATIC
13
2
45
6
8
157
9
1110
13
16
J.303-1287
9
10
12
14
Key :
1. MAF sensor
2. IAT sensor
3. TP sensor
4. Throttle motor
5. AAC valve
6. IP sensor8
11
16
1616
7. EFT sensor
8. Fuel injectors
9. CMP sensor
10. Coil-on-plug units
11. VVT shuttle valve
12. ECT sensor13. KS sensors
14. CKP sensor
15. EOT sensor
16. HO2 sensors

V8 Engine AJ-V6/AJ28
56
Fuel Injection
Returnless Fuel System
The function and operation of the returnless fuel
system is the same as that fitted to the V6 engine
but with different fuel pipework to suit the V8
layout. The air assisted, top fed, fuel injectors are
supplied from two separate rails joined by an
interconnecting cross-over pipe (similar to AJ27)
with a single common feed from the fuel tank.
The fuel rail assembly is removeable. An engine
fuel temperature (EFT) sensor and injector
pressure (IP) sensor provide feedback to the PCM
to control the fuel pump flow rate (see ÔS-TYPE
IntroductionÕ Technical Guide). Note that the EFT
sensor is not in direct contact with the fuel (ÔdryÕ
type sonser).
J.303.1390
FUEL RAIL ASSEMBLY
IP Sensor
EFT Sensor
J.303.1390

Automatic TransmissionAJ-V6/AJ28
61
Introduction
The 5R55N type 5-speed automatic transmission is fitted to both the V6 and V8 engines. The
transmission is controlled electronically by the powertrain control module (PCM) without the use of a
dedicated control module. Normal P, R, N, D drive functions plus manual selection of 4th, 3th and 2nd
gears are provided by a Jaguar style ÔJÕ gate (not the same as XJ and XK Series - see ÔS-TYPE IntroductionÕ
Techical Guide). Sports mode and traction assistance are selected at the ÔJÕ gate.
Specification
Transmission weight with fluid: 90 kg (198 lbs)
Oil type: Mercon V semi-synthetic (not compatible with other fluids)
Oil capacity: 9 Litres (9.5 quarts) - new
5 Litres (5.3 quarts) - after draining
Oil Fill/change: Filled for life, no top up required (no dipstick)
Gear ratios: 1st 2nd 3rd 4th 5th Rev
3.24 : 1 2.44 : 1 1.55 : 1 1 : 1 0.75 : 1 3.07 : 1
D.307.313
5R55N AUTOMATIC TRANSMISSION
D.303.313
Vent Tube
Turbine Speed
Sensor
Intermediate
Speed Sensor
Output Speed
Sensor
Range Switch
Rear Mounting
BracketJ-gate Selector
Cable Lever

Automatic TransmissionAJ-V6/AJ28
63 controlled solenoid are mounted on an
integral, replaceable, control module
¥ three speed sensors mounted on the external
casing: turbine speed sensor, intermediate
speed sensor and output speed sensor
¥ an oil temperature sensor is fitted inside the
transmission.
The gear select lever is connected via a Bowden
cable to an operating lever on the left side of the
transmission casing. A digital rotary switch, the
transmission range switch, fits over the shaft of
the operating lever and is fixed by two bolts to
the transmission casing. Selection of a particular
drive function generates a 4 bit binary coded
signal which is transmitted directly to the PCM
over a four wire parallel interface. As on the XK
and XJ Series, lateral movement of the gear select
lever across the gate, D to 4 or 4 to D, operates a
switch which indicates the selected function to
the PCM (the Bowden cable is not actuated
laterally).
The PCM directly controls the transmission
actuators as a response to driver demand, engine
requirements and according to the selected shift
mode. Gear selection is controlled by commands
to the four shift solenoids. If, during gear
selection, the relative speeds monitored by the
speed sensors are not as expected, the PCM
varies the analogue signal to the variable force
solenoids to increase/decrease the clutch pressure
(closed loop control). Increased engagement times
due to ageing are also controlled by adaptive shiftpressure.
Apart from the sports mode and traction mode
selected by the driver, there are pre-programmed
modes selected by the PCM in response to sensed
driving conditions :
¥ increased load such as gradients and trailer
towing
¥ cruise control
¥ hot mode: strategies including clutch lock up
are applied to reduce heat.
Transmission Oil Cooler
The transmission fluid is cooled externally by a
dedicated oil to air radiator which is mounted in
the integral cooling pack between the engine
radiator and A/C condenser and below the PAS
cooler.
D.307.320
TRANSMISSION OIL COOLING
Transmission
Oil Cooler
D.307.320

Introduction
Manual Transmission AJ-V6/AJ28
64In Europeon markets only, manual transmission is fitted as standard on the V6 entry S-TYPE model and
as an option on the V6 high specification model. Manual transmission is not available for the V8 variant.
The manual transmission is a 5 speed Getrag 221 unit with the following features:
¥ direct gearing (1:1) on 5th gear (it is normally on 4th) reduces losses
¥ twin synchronising cones on 1st and 2nd gears provide a smoother change
¥ four plane shift gate (R-1-3-5) with Ôknock-overÕ protection on the Reverse position.
A reverse light switch and speed sensor are fitted on the LH side of the gearbox. The speed sensor
monitors output shaft speed to provide an input to the PCM in addition to the signals received from the
road wheel speed sensors.
Specification:
Gear ratios: 1st 2nd 3rd 4th 5th Reverse
4.23 : 1 2.52 : 1 1.67 : 1 1.22 : 1 1 : 1 4.14 : 1
Weight: 33 kg (72 lbs)
Oil specification: ESSOD21065
Oil change interval: 60,000 miles (96,000 km)
D.307.312
MANUAL TRANSMISSION, CLUTCH ASSEMBLY AND DUAL MASS FLYWHEEL
D.307.312
Reverse Light Switch
Speed Sensor

Manual Transmission AJ-V6/AJ28
66With a conventional clutch, increased lining wear
causes the angle of the actuating diaphragm
spring to change as the pressure plate moves
axially towards the engine, requiring a greater
force to operate the clutch (diaphragm actuating
force varies with diaphragm angle). The self
adjusting clutch eliminates the problem by
allowing the diaphragm spring to follow the axial
movement of the pressure plate thus maintaining
the diaphragm spring at the same angle
throughout the life of the clutch. As well as
maintaining a constant pedal pressure, the clamp
force on the pressure plate also remains constant
with wear.
The operation is shown in the diagram. The
diaphragm spring is not fixed at its rotation point
like the conventional system but pivots between a
sensor spring and an adjuster ring. The sensor
spring provides a counter force which is just
sufficient to retain the diaphragm spring axially
against the cover via the adjuster ring and during
normal actuation of the clutch. As the linings
wear, the tendency of the diaphragm angle to
change causes an increase in the actuation force
required to operate the clutch. When this
increased effort exceeds the counter force of the
sensor spring, the diaphragm spring moves axially
towards the pressure plate until the original angle
is restored. At this point the actuation force
required drops to the level of the opposing sensor
spring force, restoring equilibrium with the
diaphragm spring at its new location.
During the axial movement of the diaphragm
spring, the increased distance between the spring
and cover is taken up by the adjuster ring. This
ring has fifteen raised segments, each having a
ramp profile which fits into a corresponding
shape in the clutch cover. When the diaphragm
spring moves axially for wear compensation,
three pre-loaded coil springs in the clutch cover
cause the adjuster ring to rotate, moving up the
ramps and taking up the extra distance between
the diaphragm spring and clutch cover.
Note that, in operation, the adjuster ring rotates
in a clockwise direction, as viewed from the
transmission. If a worn driven plate is replaced in
service and the clutch cover assembly is to be re-
used, the adjuster ring must be rotated back to its
pre-loaded position (see JTIS service instructions).
J.307.318
DUAL MASS FLYWHEEL AND CLUTCH ASSEMBLY
J.307.318
J.307.319
OPERATION OF SELF ADJUSTING CLUTCH
J.307.319
Dual Mass
Flywheel
Assembly
Self Adjusting
Clutch
Driven Plate
Concentric
Slave Cylinder
Adjuster
Ring
Conventional
Clutch
Sensor Spring
Diaphragm
Spring
Self Adjusting
Clutch
Diaphragm
Spring

Powertrain ManagementAJ-V6/AJ28
69
Introduction
All powertrain and associated management
functions are controlled from a single unit, the
powertrain control module (PCM). These
functions are as follows:
¥ overall monitoring and control of
performance, fuel economy, emissions,
driveability and safety
¥ receives and processes direct inputs from
engine, transmission, fuel system and
ancillary systems sensors
¥ provides direct control of actuator devices
¥ communicates with other modules via the
SCP bus (eg to obtain wheel speed
information)
¥ provides system diagnostics to conform to
OBDII requirements.
Powertrain Control Module (PCM)
The basic PCM is common to the V6 and V8
engines but with unique programming to suit the
respective engine characteristics and some
differences in the interface circuits for the
different sensors and actuators.
The PCM is located below the LH or RH mounted
A/C evaporator/blower unit and has a single
connector panel which protrudes through the
forward bulkhead into the engine bay.
The PCM has three connectors:
¥ a 60 pin connector which provides the
interfacing with the engine wiring harness:
carries engine mounted sensor inputs and
output control signals
¥ a 32 pin connector which carries the
transmission sensing and control signals and
also the rear HO2 sensor inputs
¥ a 58 pin connector which carries non engine
mounted sensor and actuator signals and
provides the PCM link to the SCP bus.
Powertrain Sub-Systems
Brief descriptions of PCM control of new
subsystems are given in the relevant engine and
transmission sections (electronic throttle,
returnless fuel etc).
J.303.1393
POWERTRAIN CONTROL MODULE
J.303.1393