1998 JAGUAR X308 vent solenoid

generates a signal when th
e dr
ive plate passes the sensor
sen
ds the ECM signals indicating crankshaft position and engine speed
is e

ssential for calculating spark timing
En

gine Coolant Temperature (ECT) Sensor
sen
ds the ECM a signal indicating the temperature of the engine coolant
is a t

emperature dependent resistor with a negative temperature coefficient (resistance changes inversely with
respect to temperature) and is constantly monitored by the ECM
Intake Air Temperature (IAT) Sensor

is m
ounted in the same housing as the MA
F sensor but is not a serviceable item
sen
ds the ECM a signal indicating the temperature of the air entering the engine
is a t

emperature dependent resistor which has a negative
temperature coefficient (its resistance changes inversely
with respect to ambient temperature).
Knock S
ensor (KS)
is a pi
ezo-electric device which sends a signal
to the ECM indicating engine detonation
Between 700 and 6800 rpm, the ECM will retard individual cylinder ignition timing when detonation occurs while allowing
the other cylinders to continue operating normally.
During acceleration, at critical load and speed conditions, the ECM retards ignition timing to prevent the onset of detonation.
H
eated Oxygen Sensor (HO2S)
are
positioned upstream of the catalytic convertor
is equipped with

a heating element wh
ich improves the response time of the sensors during engine warm-up
h
as the ability to generate a voltage signal proportional to the oxygen content of the exhaust gases leaving the
engine
pr
ovides feedback information to the ECM used to calc
ulate fuel delivery and provide optimum gas emissions
Variable V
alve Timing (VVT) Solenoid
R
efer to section 303-01.

Input speed is monitored by the TCM with a rationality check being made against output speed. A fault will be flagged if the
indicated input speed exceeds 7400 rpm. Additionally, a failure judgement will be made if the indicated input speed is <160
rpm with engine speed >608 rpm and output speed >224 rpm
The procedure is similar for the output sp eed diagnostic. A fault (non OBDII) will be flagged if the indicated input speed
exceeds 6712 rpm. Additionally a failure judgement will be ma de if the indicated output speed is <160 rpm and the average
road wheel speed exceeds 100 rpm.
Under normal circumstance s after the output speed diagnost ic fault code has been set, the TCM uses rear wheel speed
information to compute its calculations, this has no effect on transmission operation. However, should a second fault occur,
in the ABS system, thus making rear wheel speed information unavailable, an additional fault code will be logged.
Control Systems
Introduction
Gear selection is achieved by controlling the flow of transmission fluid to internal multi-disc clutches.
The three solenoid valves direct the transmission fluid flow to the selected clutches and the pressure regulators control the
fluid pressure to each component. One pr essure regulator serves as a master pressure control for the entire system and a
second is used exclusively for torque converter clutch lock-up operation.
The TCM controls the internal components thus determining gear selection and shift pattern.
In the event of an electronic system fault the basic function s Park, Reverse Neutral and Drive Fourth are retained by the
hydraulic system.
Transmission Control Module (TCM)

The TCM is located in the same housing as th e ECM and is accessed in the same manner.
The TCM performs several 'self check' procedur es to ensure correct operation. It is possible due to the nature of these faults
that the module will fail to communicate with other nodes. However, condemnation of the TCM should not take place until
any CAN or power supply related problems have been resolved.
There are three self check procedures for the TCM. 1. 1. Check on ROM by calculatin
g a checksum and comparing this with a known stored value.

6. Remove the output speed sensor.
• NOTE: M6 fixing.
1. Remove the screw from the output speed sensor
securing bracket and pu ll the sensor clear.
Disconnect the harness multiplug.

7. Disconnect the five pressure regulator connectors and three
solenoid connectors.

8. Reposition the internal harness for access.
Release the internal harness from the retaining clips.

9. Drain the valve body.
1. Position a suitable drain tin below the valve body.
2. Slacken (do not remove) the twenty-two screws, valve body to transmission case.
Allow the fluid to drain.
10. Remove the valve body.
Remove five M6 X 30 screws, valve body to transmission
case.
Remove seventeen M6 X 60 screws, valve body to
transmission case.

Stator, intermediate and output shafts. Three epicyclic geartrains. Six multi-disc clutch/brake packs. Two freewheels (One-way clutches). Hydraulic pump. Parking lock assembly. Electro-hydraulic control unit. Internal harness and 13 pin connector with bayonet lock.
Hydraulic pump
This engine driven pump is located at the front of the transmission casing and provides pressure for the hydraulic
functions.
Supplies fluid under pressure to the torq ue converter, geartrain, electro-hydraulic control unit and the lubrication
circuit.
Draws fluid from the fluid pa n below the transmission casing, through a filter.
Parking lock
This component prevents movement of th e vehicle by engaging a fixed pawl with the parking lock gear located on the
output shaft. The pawl is engaged by movi ng the gear selector lever to the park (P) position.
Electro-hydraulic control unit
This unit, mounted in the transmission lower case, converts signals, mechanical from the J-gate and electrical from the
TCM, into hydraulic functions.
The following components ar e assembled to the unit:
Selector valve. Shift plate. Control valve - modulating pressure. Control valve - shift pressure. Solenoid valve 1 <-> 2 and 4 <-> 5 shift. Solenoid valve 3 <-> 4 shift. Solenoid valve 2 <-> 3 shift. Solenoid valve - converter lock-up. Speed sensors (2). Temperature sensor.
Speed sensors
There are two speed sensors within the transmission assembly which provide input to the TCM. These inputs, when used in
conjunction with CAN data relative to engine speed (from ECM) and road speed (from ABS), are used to electronically
control the transmission.
Temperature sensor
The output from this sensor allows the TCM to compensate for the affect of fluid temperature on shift time and quality
Control Systems
Hydraulic Control
The selector valve is operated directly by the J-gate and directs fluid flow for P R N D.
Of the four solenoid valves, 3 control shifts and 1 controls converter lock-up. One control valve controls modulating pressure
and the other shift pressure.
Regulating valves are used to maintain/control pressure for lu brication, normal operating functions, and the supply to the
control valves and shift valves.

CAN Input Signals
Traction status ABS malfunction ABS status Engine torque status Throttle position Accelerator pedal position Engine torque reduction confirmation Engine speed Engine coolant temperature Cruise status OBDII fault code clear request Throttle malfunction warning RED or AMBER All road wheel speeds Token for network status ECM Token for network status INST Token for network status ABS Diagnostic data in from external device (PDU)
Output Signals
Solenoid valve 1 <-> 2 and 4 <-> 5 shift Solenoid valve 2 <-> 3 shift Solenoid valve 3 <-> 4 shift Solenoid valve converter lock-up clutch Control valve - modulating pressure Control valve - shift pressure
CAN Output Signals
Engine torque reduction request MIL status (whether present DTC should operate MIL) Transmission input speed Transmission output speed Converter slip Kickdown status Gear position (actual) Gear position (selected) Gear selection fault Converter lock-up status Current selected shift map Transmission oil temperature Transmission malfunction Pecus flag (state of current TCM program) Target for next gear position Gear shift torque transfer progress at shift MIL status (response to activate the MIL relevant to a DTC) OBDII fault code clear acknowledgement Transmission DTCs (P codes) Token for network status TCM Diagnostic data out to external device (PDU)
Emergency Running (elect ronic limp-home mode)
The TCM constantly monitors the transmissi on for faults. In the event of a problem the TCM will adopt the limp-home mode, in which the gear currently held remains engaged, until P is selected. The modulati ng and shift pressures will increase to
maximum and converter lock-up will be inhibited.
Following the selection of P , the only ratios available will be 2 (irrespective of forward ratio manual selection) and R .
With the vehicle at rest, the procedure to manually select is as follows:
1. 1. Select P .

Range Selection
The 'J' gate selector lever is connected to the transmission via a cable which operates the transmission selector shaft
between positions P R N D only. The shift lever disconnects from the cable when the lever is moved across the gate from D
to 4 .
Movement of the lever between P R N D manu ally controls the flow of transmission fluid, the TCM having control of the
forward gear selected in D .
Movement of the lever to 4 , 3 and 2 positions does not manu ally modify the fluid flow, the TCM detects these positions
using the DLS and controls the ratios electronically by energizing solenoids.
Shift Point Control
The gearshift points are controlled by the TCM, as a function of the output speed, engine load, engine speed, selector
position and shift program selected. The operator has control over the shift points via the shift lever, throttle pedal
movement, kickdown function and mode switch.
Mode Switch
This switch allows operator selection of two base shift modes; Normal and Sport; th e switch being illuminated when Sport is
selected. This function alters the values in the TCM shift point calculations.
Shift Programs
Upon encountering the following conditions, the TCM will auto matically modify the Normal or Sports shift map to enhance
the operation of the vehicle:
1. 1. Traction: When traction intervention is active.
2. 2. Hot mode: Extreme engine/transmission temperatures.
3. 3. Gradient: Under specific speeds and loads.
4. 4. Manual: Driver initiated override of the normal shif t map when the LH side of the 'J gate' is used.
Traction
When traction or stability control (engine or brake system de rived) is operational the TCM will implement the traction map
to maximize control of wheel slip.
Gradient
The gradient function is intended to enhance vehicle drivea bility when climbing a gradient or towing. The TCM will
implement the function when increased driving resistance is de tected, and provides enhanced driveability, additional cooling

The Drive-to-fourth switch:
Detects when the gear selector lever is moved from Drive to Fourth. Is hard-wired to the transmission control module.
The Neutral position switch:
Is hard-wired to the body processor module. Detects when the gear selector lever is moved to the Neutral position.
The Park position switch:
Is hard-wired to the body processor module. Detects when the gear selector leve r is moved to the Park position.
The gear selector module:
Provides illumination of the gear sele ctor surround, which is dimmable via a CA N signal from the instrument cluster. Provides red illumination, on the gear selector surround, of the gear selected, by CAN signals from the instrument
cluster.
Illuminates the security system Active LED on the gear se lector surround, in response to an input from the body
processor module.
Is connected to the fascia harness via a 12-way connector. Refer to Connec tor Pins Identification, 307-01A.
The gear selector interlock solenoid:
Prevents the gear selector lever from be ing moved from the Park position, unless th e ignition switch is in position II,
and the brake pedal is depressed.
Is controlled by an input from the body processor module.
The seven gear selector positions are:
P : The transmission is mechanically locked (starting available). R : Reverse gear. N : No power to the rear wh eels (starting available). D : All 5 forward gears available. 4 : Upshift to 4th gear only. 3 : Upshift to 3rd gear only. 2 : Upshift to 2nd gear only.
Performance Mode Pushbutton

The performance mode pushbutton:
Is mounted on the gear selector surround. Selects Normal or Sport mode when pressed by the driver. Is illuminated when Sport mode is selected.

Selector lever:
Gear selector positions are:
P Transmission mechanically locked, starting available * R Reverse gear N Neutral gear, no power to the rear wheels (starting available) D Drive gear, all 5 forward gears available (see Performance Mode Pushbutton) 4 Upshift to 4th gear only 3 Upshift to 3rd gear only 2 Upshift to 2nd gear only
Gearshift Interlock Manual Override*
The interlock system which locks the sele ctor in P and prevents the ignition key from being removed except when P is
selected, may be manually overridden in the event of an emergency.
1. 1. With the parking brake applied
2. 2. Remove the access blank using a suitable Torx bit
3. 3. Insert a small screwdriver into the vacated hole
4. 4. Push the screwdriver downwards, gently, and hold whilst simultaneously moving the selector from P towards R ,
but do not engage R until the tool has been removed
5. 5. An audible warning may be heard when operation 4 is carried out
6. 6. With the selector in N and the access bl ank replaced, the vehicle may be started
Range Selection
The selector lever transmits operator demand to the transmission and TCM by means of a cable and Dual-Linear
Switch (DLS).
The lever operates the transmission assemb ly selector shaft, only for P R N D , by means of a cable. Movement of the
lever across the gate to 4, 3 and 2 positions disengages th e cable from the selector lever and engages the DLS which
controls gear selection electronically.
Gear selector module:
Provides illumination of the decal relevant to the gear sele cted. This information is provided by CAN from the TCM. Illuminates the security system Active LED on the gear selector surround, in response to an output from the BPM.
Transmission Switches
Performance Mode Pushbutton
7—Connector - Climate control
8—Solenoid - Gear selector
9—Security system Active LED