1994 JAGUAR XJ6 Diagnostic

Introduction
FOREWORD
This Vehicle Service Manual (VSM) is Dart
-
of a
set of service literature which covers -. diagnosis and rectification of problems associated with all areas of the X300 family of vehicles.
It is designed to be read in conjunction with other manuals, namely the various Unit Service Manuals (USM) (as
applicable to the particular vehicle under diagnosis/ repair) and the X300 Electrical Diagnostic Manual (EDM); see list
below.
It should be noted that its scope is limited to those areas that are unique to the family, e.g. Remove & Refit procedures
for Body Components, Engine, Transmission etcetera, Fuel, Emissions & Engine Management systems, and so on.
Fault Diagnosis and repair procedures (together
with Technical Data, Recommended Lubricants, Capacities etcetera) for major assemblies such as engines, automatic and manual transmissions, are covered in the separate Unit Service
Manuals.
The Unit Service Manuals are notvehicle
-specific, but are designed to be read in conjunction with this VSM, and, where so equipped, with other Jaguar Vehicle Service Manuals for new models launched subsequent to the X300 family.
The X300 Electrical Diagnostic Manual is the final part of the 'set' of service documentation. This manual
is
family-specific, and is designed to aid theTechnician to isolate electrical faults and to correct them. It covers all aspects
of electrical fault diagnosis, including:
OBD
II Codes and emission control system related fault diagnosis / rectification.
Circuit Diagrams
Component (Relays, fuse boxes, control modules etcetera) Location
/ Harness Diagrams I Ground Locations
Connector Locations.
Service Manuals Required
The Manuals required to service the X300 family of vehicles are as follows:
X300 Vehicle Service Manual
X300 Electrical Diagnostic Manual
Unit Service Manuals:
AJ16 Engine Service Manual
VI2 Engine Service Manual ZF AutomaticTransmissions Service Manual (ZF supplies transmissions for 3.2 liter and 4.0 liter normally aspirated
versions) Powertrain Automatic Transmissions Service Manual (The Powertrain name succeeds that of Hydra
-Matic.
Powertrain are suppliers of the 4L 80 E transmission as fitted to 4.0 litre supercharged and 6.0 litre versions)
Each
of the X3Okpecific manuals is divided into Sections which adopt the same title and number where relevant, i.e. Section 5.1 of both the VSM and the EDM cover Fuel, Emission Control & Engine Management System (AJ16). An
over
-all contents list showing each section title and number together with its page-edge locator is given in this section
and in the introduction to the EDM.
The VSM (not applicable to the EDM) also contains Appendices which cover specialized areas such as the current
vehicle specification, routine maintenance schedule etc. These are carried at the rear of this Manual, and have their
own contents page within this section.
INDEX
rapid location of information. The entries are set out as per the following example: @ This manual carries a comprehensive index at the rear, which is designed to save the Technician time by permitting
CLIMATE CONTROL SYSTEMS. Section 14.
See also Electrical Diagnostic Manual
Clutch
Description: Sect. 7.7 - 10
Fault diagnosis: Sect 7.1 - 11
In the example the heading in upper case lettering is to a section title, and it refers to the section number, 14, and also to the EDM as electrical diagnostic information will be found in that manual's section 14. The entry for clutch tells us that the relevant description will be found on page 10 of Section 7.1 of this manual, and
that fault diagnosis procedures start on page 11. In this case there is no reference to the EDM as electrical diagnosis does not apply to this area.
GLOSSARY OF TERMS
This Section contains a Glossary of general and emissions-related terminology (commencing on page 5).
X300 VSM 1 Issue 1 August 1994

Introduction
Term(s) Abbreviation Definition
(if applicable) Previously
used term(s) (or Eng-
lish Equivalent)
downshift
draft _.
drivability
driveshaft
driveshaft tunnel
dry sleeve
Dual Overhead Cam
Data
Data Link Connector
Data Output Line
defogger, backlight defogger
degree (angle or temperature)
Department of Transportation
(US)
Department of Transport (UK)
Deutsche lnstitut fur
Normuna
diameter
Diagnostic Module
Diagnostic Test Mode
Diagnostic Trouble Code
differential housing
differentia
I pressure
Differential Pressure Feedback
EGR
dimmer switch DOHC
DLC
DOL
deg, O
DOT
DTP DIN dia
DM
DTM
DTC
DPFE longitudinal
shaft transmitting power from
transmission output to rear axle differential
tunnel
in floor above the driveshaft (propeller
shaft)
cylinder sleeve which is not in contact with
coolant
engine configuration with two camshafts
positioned above the valves
(US) Fact or group of facts.
connector providing access
andlor control of
the vehicle information, operating
conditions, and diagnostic information
circuit that sends certain information from
the PCM to the instrument cluster
German Standards regulation body
Supplemental Restraint System
(non-controlling) module for diagnostics
overview
a level of capability in an OBD system. May
include different functional states
to observe
signals, a base level to read
DTCs, a monitor
level which includes information on signal
levels,
bi-directional control with onloff board aids, and the ability to interface with
remote diagnosis
an
alphahumeric identifier for a fault
condition identified by the On
-Board
Diagnostic
(OBD) system
rotating housing
(in a bevel differential)
attached to the crownwheel, carrying the
final drive pinions
pressure difference between two regions e.g.
between intake manifold and atmospheric
pressures
an EGR system that monitors differential
EGR pressure across a remote orifice
to control EGR flow change
down
draught
driveability
propeller shaft
transmission
tunnel
dry liner
(English) Group
of facts (i.e. plural
of
datum)
HRW, rear screen
heater, demister
Self Test Mode
Self Test Code.
Fuel Fail code
differential cage
dip switch,
dipper switch
Issue 1 August 1994 11 X300 VSM

GLOSSARY Of
Term(s) Abbreviation Definition Previously used (if applicable) term(s) (or Eng- lish Eauivalent)
U
undercoating
unitized construction
Unit Service Manual
V
valve
valve lifter
vapor Vehicle Condition Monitor
Vehicle Emission Control
Information Label
Vehicle Service Manual
Vehicle Speed Sensor
Vehicle Identification Number
Viscositv Index
volatile
Voltage Regulator VCM
VECl Label
VSM
vss
VI N
VI
VR Service
Manual which pertains
to a major
'unit' (e.g. transmission, engine) fitted to a
Jaguar vehicle (see also Vehicle Service
Manual and Electrical Diagnostic Manual)
a device
by which the flow of liquid, gas,
vacuum or loose materials may be started,
stopped or regulated by a movable part
which opens, shuts or partially obstructs one
or more passageways or ports.
A 'Valve' is
also the movable part of such a device
in an OHC engine, the plunger fitted between
valve stem and cam lobe
instrument panel display which warns of
faults
Service Manual which pertains to a specific
family of Jaguar vehicles (see
also Unit
Service Manual and Electrical Diagnostic
Manual).
sensor which provides vehicle speed
information
number assigned to the vehicle
by the
manufacturer, primarily
for licensing and
identification purposes
(1) vaporizing at room temperature (liquid) (2) not permanent (memory)
device which regulates the variable output
voltaae of a aenerator underseal
unitary
construc
-
tion
tappet, bucket
vapour
road speed sen
- sor
Issue 1 August 1994 27 X300 VSM

Cooling System
SECTION CON TENTS
Sub-section Title SRO Page
I to IV ............ Preliminary Pages .................................................................... i
4.7.7 ............. Cooling System Description ........................................................... 7
4.1.7.7 ........... Cooling System Description. Major Components .......................................... 7
4.7.7.2 ........... Cooling System Description. Components for Climate Control System ........................ 7
4.7.1.3 ........... Cooling System Description. Components for Superchargwl Engine .......................... 7
4.7.7.4 ........... Cooling System Description. Operation .................................................. 7
4.7.2 ............. Cooling System Configuration .......................................................... 2
4.7.3 ............. Service Procedures ................................................................... 3
4.7.3.7 ........... Service Procedures. Safety Precautions .................................................. 3
4.7.3.2
........... Service Procedures. Working Practices .................................................. 3
4.7.3.3
........... Service Procedures. Coolant Change .................................................... 3
4.7.4.
............ Drain and Fill Procedures ............................................................. 4
4.7.4.7
........... Drain and Fill Procedures. Radiator, Drain ............................................... 4
4.7.4.2
........... Drain and Fill Procedures. Engine. Drain ................................................. 4
4.1.4.3
........... Drain and Fill Procedures. Radiator, Fill ................................................. 4
4.7.4.4
........... Drain and Fill Procedures. Complete System. Fill .......................................... 5
4.7.5 ............. Fault Diagnosis ...................................................................... 6
4.1.5.7 ........... Fault Diagnosis. Introduction ........................................................... 6
4.7.5.2 ........... Fault Diagnosis. Diagnostic Procedures .................................................. 6
Issue 1 August 19! X300 VSM i

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

Diagnostic Procedures (continued)
Symptom
Loss of cool-
Possible Cause Check
Loose clips on hoses
Hoses perished Visual check
Radiator core leaking Pressure
-test system
Water
pump seal leaking Pressure-test system
Thermostat gasket leaking Pressure
-test system. (Check
for distortion of thermostat
housing)
Inspect cap or test cap spring
pressure
Pressure
-test system. Check
strength of coolant
Pressure
-test system. Check
for contamination of coolant
and engine lubrication system
Identify
component(s)
contamination of engine
lubrication system)
Check
clips for correct
tight-
ness
Header tank cap defective
Porosity
in castings Pressure-test system
Corrosion caused by con
-
centration of anti-freeze being
too low
Cylinder head gasket leaking
Cracked or damaged internal
engine component affected. (Check for
Remedy
Tighten clips as required
Renew hoses as required
Repair or renew radiator
Renew water
pump
Renew gasket. Renew hous-
ing if required
Renew cap
Rectify as required
Rectify as required. Drain and
fill with coolant of correct con-
centration
Renew head gasket
Rectify as required

SECTION CON TENTS
Subsection Titie SRO Page
it0 IV ............ Preliminarypages .................................................................... i
4.2.1 ............. Cooling System Description ........................................................... 1
4.2.1.1 ........... Cooling System Description. Major Components .......................................... 1
4.2.1.2 ........... Cooling System Description. Components for Climate Control System ........................ 1
4.2.1.3 ........... Cooling System Description. Operation .................................................. 1
4.2.2 ............. Cooling System Configuration .......................................................... 2
4.2.3
............. Service Procedures ................................................................... 3
4.2.3.1
........... Service Procedures. Safety Precautions .................................................. 3
4.2.3.2
........... Service Procedures. Working Practices .................................................. 3
4.2.3.3
........... Service Procedures. Coolant Change .................................................... 3
4.2.4
............. Drain and Fill Procedures ............................................................. 4
4.2.4.1
........... Drain and Fill Procedures. Radiator, Drain ............................................... 4
4.2.4.2
........... Drain and Fill Procedures. Radiator, Fill ................................................. 4
* 4.2.4.3 ........... Drain and Fill Procedures. Complete System. Fill .......................................... 4
4.2.4.4
........... Drain and Fill Procedures. System. Air Bleeding ........................................... 4
4.2.5
............. Fault Diagnosis ...................................................................... 5
4.2.5.1
........... Fault Diagnosis. introduction ........................................................... 5
4.2.5.2
........... Fault Diagnosis. Diagnostic Procedures .................................................. 5
X300 VSM i 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