1998 JAGUAR X308 Electronic engine controls

Th
e engine management system provides optimum control of
the engine under all operating conditions using several
strategically placed sensors and any necessary actuators. Electronic engine control consists of:
engine
control module
throttle posi

tion sensor
engi

ne coolant temperature sensor
cam

shaft position sensor
c

rankshaft position sensor
mass air

flow sensor
intake air temper

ature sensor
kn

ock sensor
heat

ed oxygen sensor
Electronic Engine Control
Engine

Control Module (ECM)

The ECM incorporates a comprehensive monitoring and diagnostic capability including software variations to ensure system
compliance with the latest diagnostic and emissions legislation in different markets. The engine control module controls the
coil on plug ignition system, electronic fuel system, cr uise control and the electronic throttle control system.
The ECM responds to input signals received from sensors relating to engine operatin g conditions and provides output signals
to the appropriate actuators. These outp ut signals are based on the evaluated input signals which are compared with
calibrated data tables or maps held within th e ECM before the output signal is generated.
The ECM needs the following inputs to calibrate the engine properly:
cam
shaft position
It
em
Par
t Number
De
scription
1—Knock

sensor
2—Engine

coolant temperature sensor
3—Cranksh

aft position sensor
4—D

ownstream oxygen sensor
5—Upstream oxygen sensor
6—Camshaft position

sensor
P
arts List
engi

ne rpm
engi

ne coolant temperature
amount

of engine detonation

E
lectronic Engine Controls -
Electronic Engine Controls
D
iagnosis and Testing
I

nspection and Verification
1.
1. Veri
fy the customer concern.
2. 2. Confirm which, if any, warning li ghts and/or messages were displayed on the instrument cluster.
• NOTE: If any warning lights and/or me ssages were displayed when the fault occurred, refer to the Driver Information
table for DTCs associated with the display, then to the DTC index table for possible sources and actions. Some warnings will
appear to clear when the ignition is cycl ed. This is often because the warning has flagged as a resu lt of one of the vehicle's
on-board diagnostic routines having run to detect the fault. If the same routine is not run when the ignition is switched ON,
the warning will not reflag until the routine does run. See the DTC summaries for drive cycle routines.
3. 3. Visually inspect for obvious signs of mechanical or electrical damage.
V
isual Inspection Chart
4.
4. Veri
fy the following syst
ems are working correctly:
Air in
take system
Coo

ling system
Charging system


F

uel charging system
5. 5. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding
to the next step.
6. 6. Where the Jaguar approved diagnostic sy stem is available, complete the S93 report before clearing any or all fault
codes from the vehicle.
• NOTE: If a DTC cannot be cleared, then there is a permanent fault present that flag s again as soon as it is cleared (the
exception to this is P1260, which will only clear following an ignition OFF/ON cycle after rectification).
7. 7. If the cause is not visually evident and the Jaguar approv ed diagnostic system is not available, use a fault code
reader to retrieve the fault codes be fore proceeding to the Diagnostic Trou ble Code (DTC) Index Chart, or the
Symptom Chart if no DTCs are set.
• NOTE: If the DTC flagged was not present for two or more co nsecutive cycles, it is classed as temporary, and will be
deleted following three cycl es during which no fault was present. This could result in a reported wa rning light/message with
no stored DTCs. If a fault is present for three consecutive cycles, the DTC becomes permanent, and will remain in the
module's memory for 40 drive cycles (a cy cle is an ignition ON/OFF, which will occur during the owner's normal use of the
vehicle. No action on the part of the technician is necessary to perform this cycle. A drive cycle is a series of conditions
needed to make the on-board diagnostic ro utine run, and may need a specific action on the part of the technician. See the
DTC summaries for driv e cycle routines).
8. 8. Using the Jaguar approved diagnostic system where available, and a scan tool where not, check the freeze frame
data for information on the conditions applicable when the fault was flagged. The format of this will vary,
dependin
g o
n the tool used, but can provide information useful to the technician in dia
gnos
in
g th
e fault.

MechanicalElectrical
Engi
ne oil level
Coo

ling system coolant
level
Fuel contamination

Throttle body Poly

-vee belt
F
uses
W

iring harness
E

lectrical connector(s)
Sens

or(s)
Engine

control module (ECM)
Tran

smission control module
Check spark plu

g type. Only re
sisted plugs should be fitted. Refer to specifications
section for gap
Relay date codes.
If the date on the rela
y is between R6 k1 and R6 k8, replace the
relay

the DT
C. TEST the system for normal operation.
No GO to R2
.
R2: CHECK TH
E APP SENSOR SENSE CIRCUIT FOR SHORT TO HIGH VOLTAGE
R
e
connect the battery negative terminal.
1
Turn the ignition swi
t
ch to the ON
position.
2
Me
asure the voltage between PI42, pin 05 (K) and GROUND.
3
Is th
e volt
age greater than 3 volts?
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 R3
.
R3: CHECK THE APP SENSOR SENS
E CIRCUIT FOR SHORT TO GROUND
Turn the ignition swi
t
ch to the OFF
position.
1
Me
asure the resistance between PI42, pin 05 (K) and GROUND.
2
Is
t
he resistance 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 R4
.
R4: CHECK THE APP SENSOR COM
MON
REFERENCE VOLTAGE AT THE SENSOR
Reconn
ect the ECM electrical connector, EM11.
1
Turn the ignition swi
t
ch to the ON
position.
2
Measure t
he voltage between PI42, pin 04 (UW) and GROUND.
3
Is th
e volt
age less than 4 volts?
Yes GO to R5
.
No
GO to R6
.
R5: CHECK THE APP SENSOR COM
M
ON REFERENCE VOLTAGE CIRCUIT
Turn the ignition swit
ch to the OFF
position.
1
Di
sconnect the ECM electrical connector, EM11.
2
Measure t

he resistance between EM11,
pin 08 (UW) and PI42, pin 04 (UW).
3
Is the res
istance greater than 5 ohms?
Yes REPAIR the high resistance circui t. For additional information, refer to the wiring diagrams. CLEAR
the DTC. TEST the system for normal operation.
No Check the ECM power supplies.
REFER to Electronic Engine Controls
in this
section.
R6: CHECK THE APP
SENSOR COM
MON REFERENCE GROUND
Meas
ure t
he resistance between PI42, pin 02 (BG) and GROUND.
1
Is th
e res
istance greater than 5 ohms?
Yes GO to R7
.
No
INST
ALL a new APP sensor. CLEAR the DTC.
TEST the system for normal operation.
R7: CHECK THE APP SENSOR COM
MON REFERENCE GROUND CIRCUIT
D
i
sconnect the ECM electrical connectors, EM10 and EM11.
1
Measure t

he resistance between EM10,
pin 20 (BG) and PI42, pin 02 (BG).
2
Measure t
he resistance between EM11,
pin 12 (BG) and PI42, pin 02 (BG).
3
Is either resistance greater
than 5 ohms?
Yes REPAIR the high resistance circui t. For additional information, refer to the wiring diagrams. CLEAR
the DTC. TEST the system for normal operation.
No Check the ECM GROUND circuits. If the GROUND circuits are sound, contact dealer technical
support for advice on possible ECM failure.
PINPO
INT TEST S : DTC P1221, P1222, P1223;
ACCELERATOR PEDAL POSITION (APP) SENSOR

CIRCUI
T 'B' RANGE/PERFORMANCE, HIGH/LOW VOLTAGE
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
S1: CHECK

THE APP SENSOR SENSE CIRCUIT FOR HIGH RESISTANCE
Di

sconnect the battery negative terminal.
1
D

isconnect the ECM electrical connector, EM11.
2
Di

sconnect the APP sensor electrical connector, PI42.
3
Meas

ure the resistance between EM11, pin 15 (R) and PI42, pin 03 (R).
4
Is th

e resistance greater than 5 ohms?
Yes REPAIR the high resistance circui t. For additional information, refer to the wiring diagrams. CLEAR
the DTC. TEST the system for normal operation.
No GO to S2
.
S
2: CHECK THE APP SENSOR SENSE CIRCUIT FOR SHORT TO HIGH VOLTAGE
R

econnect the battery negative terminal.
1
Turn the ignition swi

tch to the ON
position.
2
M
easure the voltage between PI42, pin 03 (R) and GROUND.
3
Is th

e voltage greater than 3 volts?
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 S3
.
S
3: CHECK THE APP SENSOR SENSE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swi

tch to the OFF
position.
1
Meas
ure the resistance between PI42, pin 03 (R) and GROUND.
2
Is

the resistance 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 S4
.
S4:
CHECK THE APP SENSOR COMMON REFERENCE VOLTAGE AT THE SENSOR
Re

connect the ECM electrical connector, EM11.
1
Turn the ignition swi

tch to the ON
position.
2
Meas
ure the voltage between PI42, pin 04 (UW) and GROUND.
3
Is th

e voltage less than 4 volts?
Yes GO to S5
.
No

GO to S6
.
S5: CHECK
THE APP SENSOR COMM
ON REFERENCE VOLTAGE CIRCUIT
Turn the ignition swi
tch to the OFF
position.
1
Di
sconnect the battery negative terminal.
2
D

isconnect the ECM electrical connector, EM11.
3
Meas

ure the resistance between EM11,
pin 08 (UW) and PI42, pin 04 (UW).
4
Is th
e resistance greater than 5 ohms?
Yes REPAIR the high resistance circui t. For additional information, refer to the wiring diagrams. CLEAR
the DTC. TEST the system for normal operation.
No Check the ECM power supplies.
REFER to Electronic Engine Controls

in this section.
S6: CHECK

THE APP SENSOR COMMON REFERENCE GROUND
Meas

ure the resistance between PI42, pin 02 (BG) and GROUND.
1
Is th

e resistance greater than 5 ohms?
Yes GO to S7
.
No

INSTALL a new APP sensor. CLEAR the DTC. TEST the system for normal operation.
S7: CHECK
THE APP SENSOR COMM
ON REFERENCE GROUND CIRCUIT

Electronic
Engine Controls -
Heated Oxygen Sensor (HO2S) RH
Remo
val and Installation
General Equipment
Remov a
l
Installation


Snap -on to
ol S6176
1. WARNING: ENSURE THAT TH E EXHAUST AND CATALYST
ARE COLD BEFORE COMMENCING WORK
Disconnect the battery ground lead.

2. CAU
TION: Make sure the wiring harness is not twisted or
damaged on removal. Failure to follow this instruction may result in
damage to the vehicle.
• NOTE: Left-hand shown, right-hand similar.
From inside the engine compartm ent, release the relevant sensor
(s) multiplug from its mounting bracket and disconnect the plug.
3. To
gain access to the sensor(s)
the front muffler assembly must
be displaced for clearance; refer to 30.10.18.

4. CAU
TION: Make sure the wiring harness is not twisted or
damaged on removal. Failure to follow this instruction may result in
damage to the vehicle.
Using the Snap-on tool S6176, remove the sensor.
1. Fittin
g is the reverse of the remo
val procedure, noting that a new
sealing washer should be used.

2. CAU
TION: Make sure the wiring harness is not twisted or
damaged on installation. Failure to follow this instruction may result
in damage to the vehicle.
Tighten the sensor to specification.
3. M
ake good the exhaust seals.

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.

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.

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