speed control JAGUAR X308 1998 2.G Repair Manual

Automatic Transmission/Transaxle - 4.0L SC V8 - AJ26 - Transmission
Description
Description and Operation
Transmission Assembly
This electronically controlled five speed unit is unique to supercharged vehicles.
Introduction

Parts List
Transmission Fluid
It is not necessary to change the transmis sion fluid in normal service; routine level checking is not required. The sealed
dipstick tube is fitted for service requir ements only, with a dipstick being availa ble as a special tool and NOT fitted as
standard.
Components and Functions
Transmission Casing
The following components are housed within the casing;
ItemPart NumberDescription
1—Torque converter housing
2—Breather
3—Transmission casing
4—Drive flange (output shaft)
5—Fluid pan
6—Selector lever

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.

In the event of a system fault, the TCM will adopt 'limp home' mode.
Electrical control
Refer to Section 307-01B.
Transmission Control Components
Transmission Control Module (TCM)
The TCM controls the transmission internal components thus determining gear selection and shift pattern.

The TCM is located in the same housing as the engine control module (ECM) and is accessed in the same manner. With the
two connectors unplugged the TCM may be withdrawn, complete with mounting bracket. The mounting bracket is secured to
the TCM by 2 locknuts.
Operation
CAUTION: Disconnection of OTHER contro l module connectors and / or the vehicle battery, may introduce fault codes
(DTCs). Following rectification and reconnection, ensu re that no induced codes exist in the TCM memory.
The TCM processes input and output in both analogue and di gital form which may be summarized in four categories:
Input Signals
Gear selector position (Dual Linear Switch x 4 inputs see 307.05) Transmission oil temperature Kickdown Speed sensor #1 Speed sensor #2 Mode switch

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

Speed Sensor / TCM Circuit Diagram

Connector Pins Identification
Connector Pin Identity Chart for EM061
5—Shift solenoid 3 <-> 4
6—TCC pressure regulator
7—Modulation pressure regulator
8—Shift pressure regulator
9—Engine compartment fuse box
10—Transmission control module
11—Transmission
ItemPart NumberDescription
1—n2 speed sensor
2—n3 speed sensor
3—Engine compartment fuse box
4—Transmission control module
5—Transmission

Automatic Transmission/Transaxle - 4.0L SC V8 - AJ26 - Diagnostic
Strategy
Diagnosis and Testing
Symptom Chart
Symptom Chart
Special Tool(s)

Digital multimeter

Generic scantool
SymptomPossible SourcesAction
DTC P0740 Torque converter clutch system
electricalHarness fault
Connector pins(s) bent , loose or corroded
*
*GO to Pinpoint Test A
*
DTC P0740 Torque converter clutch system stuck
onTorque converter clutch stuck on
*GO to Pinpoint Test B
*
DTC P1744 Torque converter clutch system stuck
offTorque converter clutch stuck off
*GO to Pinpoint Test B
*
DTC P0702 Transmission control system electricalHarness fault
High side switch (FET) fault
Connector pins(s) bent , loose or corroded
*
*
*GO to Pinpoint Test C
or D
*
DTC P0753 Shift solenoid A electricalHarness fault
Solenoid open circuit
Solenoid short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test C *
DTC P0758 Shift solenoid B electricalHarness fault
Solenoid open circuit
Solenoid short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test C *
DTC P0763 Shift solenoid C electricalHarness fault
Solenoid open circuit
Solenoid short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test C *
DTC P0748 Pressure control solenoid electricalHarness fault
Pressure regulator open circuit
Pressure regulator short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test D *
DTC P1748 Pressure control solenoid B electricalHarness fault
Pressure regulator open circuit
Pressure regulator short
Connector pins(s) bent
, loose or corroded
*
*
*
*GO to Pinpoint Test D *
DTC P0702 Transmission control system electricalHarness fault
Speed sensor voltage supply out of
tolerance Connector pins(s) bent , loose or corroded
*
*
*GO to Pinpoint Test E
*
DTC P0715 Input / turbine speed sensor circuit
malfunctionSpeed sensor n2 or supply open circuit
Speed sensor n3
Harness fault
Connector pins(s) bent , loose or corroded
*
*
*
*GO to Pinpoint Test F
*
DTC P1601 Internal control module computer errorFaulty TCM
*GO to Pinpoint Test G *

The performance mode pushbutton:
Is mounted on the 'J' gate surround. This 'push-on push-off' swit ch selects Normal or Sport mode ( push-on for Sport) Is illuminated when Sport mode is selected. Is hard-wired to the transmission control module.
With 'Normal' selected the transmissi on will start off in 2 nd gear with kickdown to 1 st being available.
'Sport' mode allows 1 st gear en gagement from rest and modifies values in the TCM shift point calculations to provide higher
upshift speeds and enhanced availability of downshifts.
Kickdown Switch

The kickdown switch:
Is floor mounted under th e accelerator pedal. Is operated by pressing the pedal beyond the full throttle position. Provides maximum acceleration on driver demand, by signalling the TCM to select the lowest gear to give maximum
wheel torque.
Gear selector interlock solenoid:
Prevents the gear selector lever from being moved from P , unless the ignition switch is in position II, and the brake
pedal is depressed.
Is controlled by an output from the BPM
Park position switch:
Is hard-wired to the BPM Detects when the gear selector lever is moved to the Park position

Speed Control - Speed
Control
D
iagn
osis and Testing
Pri
n
ciples of operation
The s
p
eed (cruise) control sy
stem is activated by an ON/OFF master switch in the J-gate surround, which has an integral
LED to indicate status.
The steering wheel switches allow the driver to set the speed, increase or decrease the selected speed, cancel and resume
the facility without his/her hand ever leaving the steering wheel
The vehicle speed can be increased an d decreased in increments of 2 kmh (1 mph) by briefly pressing the + or - buttons up
to a maximum of five times.
Alternatively, the + or - button can be held until th e desired speed is reached.
The selected speed (by whichever method) w ill be displayed in the message center.
The system will not function at speeds below 26 kmh (16 mph), and can be cancelled from the master switch, the steering
wheel switches, and by depressing th e brake pedal. The system can be overridden by accelerating as normal.
In
spection and Verification
1.
1. Veri fy the customer concern.
2. 2. Vis
ually inspect for obvious signs of mechanical or electrical damage.
3. 3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding
to the next step.
4. 4. If the cause is not visually evident, verify the symptom, check for DTCs and follow the routines in this section.
Vi
sual Inspection Chart
Diagnostic Trouble Code (D
TC) index
MechanicalElectrical
Throttle body mechan
ism
Throttle body actuator
Module Switch(es) Instrument cluster
DTC

De
scr
iption
Possib
l
e Source
Acti
o
n
P0566Speed
c
ontrol
CANCEL
switch ON fault
Speed
control switches internal steering wheel
short circuit to ground
St
eering wheel cassette reel short circuit to
ground
Cassette reel to ECM circ
uit short circuit to
ground
CANCEL
switch failure (stuck ON)
Fo
r

CANCEL switch circuit
tests,GO to Pinpoint Test A.
P0567Speed c
ontrol
RESUME
switch ON fault
Speed
control switches internal steering wheel
short circuit to ground
St
eering wheel cassette reel short circuit to
ground
Cassette reel to ECM circ
uit short circuit to
ground
RESUME swit
ch failure (stuck ON)
For

RESUME switch circuit
tests,GO to Pinpoint Test B.
P0568Spee
d control switch
ground malfunction
Speed
control switches internal steering wheel
open circuit
St
eering wheel cassette reel open circuit or
high resistance
Cassette reel to ECM ci
rcuit open circuit or high

For

ACCEL/DECEL switch circuit
tests,GO to Pinpoint Test C.

Pinpoint test
s
re
sistance
ACCEL/DECEL
swi
tch failure
P0569Speed

control
DECEL/SET
(SET-) switch ON fault
Speed
control switches internal steering wheel
short circuit to ground
S
teering wheel cassette
reel short circuit to
ground
Cassette reel
to ECM ci
rcuit short circuit to
ground
DEC
EL/SET
switch failure (stuck ON)
Fo
r
DECEL/SET (SET-) switch
circuit tests,GO to Pinpoint Test D.
P0570Speed
control
ACCEL/SET
(SET+) switch ON fault
Speed
control switches internal steering wheel
short circuit to ground
S
teering wheel cassette
reel short circuit to
ground
Cassette reel
to ECM ci
rcuit short circuit to
ground
ACC
EL/SET
switch failure (stuck ON)
Fo
r
ACCEL/SET circuit tests,GO
to Pinpoint Test E.
P1571Brake sw
itch malfunction
Brake sw
itch to ECM circuit open circuit, short
circuit to ground, high resistance
Brake sw
itch ignition switched ground circuit
open circuit
Brake sw
itch failure
Brake ca

ncel switch to
ECM circuit open circuit,
short circuit to ground, high resistance
Brake ca
ncel switch to speed control switch
circuit open circuit, shor t circuit to ground, high
resistance
Brake ca
ncel switch ignition switched power
supply open circuit
Brake ca
ncel switch failure
Spe

ed control switch failure
For brake swi
tch circuit tests,GO
to Pinpoint Test F.
P
INPOINT TEST A : DTC P0566; SPEED
CONTROL CANCEL SWITCH ON FAULT
WAR
NING: Where tests involve the removal of the steering
wheel, and/or disconnection of air bag connectors, the
procedure for disarming air bags must be followed,
REFER to: Air Bag Supplemental Re straint System (SRS)

(501-20B Supplemental Restra
int System, Description and
Operation).
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1: CHECK

THE SPEED CONTROL SWITCHPACK IN
TERNAL CIRCUITS FOR SHORT TO GROUND
Di
sconnect the battery negative terminal.
1
Di

sconnect the speed control switch
pack electrical connector, SW02.
2
R
econnect the battery negative terminal.
3
Meas

ure the resistance between SW
02, pin 06 (BO) and GROUND.
4
Meas
ure the resistance between SW
02, pin 03 (SG) and GROUND.
5
Is either resi
stance
less than 10,000 ohms?
Yes REPAIR the short circuit. For addi tional information, refer to the wiring diagrams. CLEAR the DTC.
TEST the system for normal operation.
No GO to A2
.
A2: CHECK
THE SPEED CONTROL CASSE
TTE REEL FOR SHORT TO GROUND
Di
sconnect the battery negative terminal.
1
D

isconnect the ECM electrical connector, EM11.
2
R

econnect the battery negative terminal.
3
M

easure the resistance between SW02, pin 06 (at the cassette reel side of the connector) and
GROUND.
4
M
easure the resistance between SW02, pin 03 (at the cassette reel side of the connector) and
GROUND.
5
Is either resi
stance
less than 10,000 ohms?
Yes REPAIR the short circuit. For addi tional information, refer to the wiring diagrams. CLEAR the DTC.
TEST the system for normal operation.