engine JAGUAR X308 1998 2.G Workshop Manual

The interference suppression module (where fitted) connects to the generator main terminal 'B +' and a ground stud on the
rear face of the generator.
A multi-plug (3 pin) is connecte d to the rear of the generator:
Pin 1 not connected. Pin 2 ignition supply to the regulator. Pin 3 output to the charge warning lamp.
Generator - Internal Circuit Diagram

As with most vehicle ac generators, there is only minimal residual magnet ism in the field (rotor) windings. To compensate
for this and to achieve high current outp ut at low engine speed, the field is excited by battery voltage supplied to the
generator at the 'IG' terminal.
To control the level of field excitation and ultimately, generator output, the voltag e supplied to the field (rotor) is controlled
by the voltage regulator.
The voltage regulator senses (at the 'B' terminal) battery terminal voltage, which within limits is proportional to the state o f
charge of the battery. The regulator then adjusts the supplied voltage between the 'IG' terminal and the regulator 'F'
terminal (a continuously variable process) to maintain the 'B+' output at a constant level.

ItemDescription
1Generator Assembly
2Voltage Regulator
3Main Terminal 'B+'
4Ignition Supply Terminal 'IG' to Rotor
5Output Terminal L to Charge Lamp
6Rotor
7Stator
8Rectifier Pack

If the field were not controlled, the 'B+' output would rise to a level which could damage bulbs and ECMs. The regulator
compares the output voltage to an intern al voltage reference circuit to achieve the controlled output of the generator.
Suppression Module

Although the output from the generator is fi nely controlled and relatively smooth, it is still a pulsed DC output at a varying
frequency proportional to engine speed.
The suppression module damps ou t any ripple which may be sensed on the main output of the generator. This prevents
possible interference via the power supply, affecting the radio reception or, where fitted, the telephone.
The module is located on the right hand side of the engine compartment, on the inner panel just above the chassis leg,
adjacent to the generator. It is secured to two anti-vibration rubber moun tings. The illustration shows the suppression
module viewed from below the vehicle.
A fuse is fitted internally to the suppression module to protect the generator output in the event of a short circuit within th e
suppression module.
Drive Belt Automatic Tensioner

Generator and Regulator - Generator
Diagnosis and Testing
Refer to PDU User Guide
Refer to the PDU User Manual for detailed instructions on testing the charging circuit.
When diagnosing the charging ci rcuit, the PDU indicates only whether the generator is charging or not charging. The reason
for this is that the PDU cannot handle the potential full charging current and that the voltage control circuits are located
within the generator assembly, making th em inaccessible by the PDU directly.
It is possible that the battery has failed. In this case, the voltage output at the generator could be correct, but the voltage
at the battery terminals, and therefore the rest of the vehicl e system, will be adversely affected by the faulty battery.
The same result is given by the PDU if the battery is faulty (generator not faulty), wiring fault (damaged or severe corrosion
at the terminals) or if th e generator is at fault.
Inspection and Verification
The following manual tests help to pinpoint which component is at fault.
Testing the Battery Circuit
Using the Vehicle Battery

Remove the battery cover.
Ensure that all electrical loads are swit ched OFF and that the engine is cool.
Start the engine and allow to IDLE.
Whilst the engine is idling, disconnect the battery negative terminal and, using a digital multimeter (DMM), measure the
voltage between the terminal on the batter y negative cable and the battery positive terminal. If the generator is working,
the measured voltage should be within the range 13V to 15V.
This indicates the system voltage without the battery in circuit. If the generator is inoperative, the engine will stall when t he
ground lead is disconnected.
Repeat the test, using the ground bolt, as indicated (shown dotted on the illustration). There should be hardly any
MechanicalElectrical
Visually check the condition of the drive beltConnections on the rear face of the generator
are fully located?
Check that the belt we ar indicator, located on the automatic belt
tensioner, is within the limit marks

detectable difference in the voltage reading (due to minimal current flow); if there is a detectable difference, clean the cable terminal and the adjacent area of the body.
When the voltage has been measured, STOP THE ENGINE.
Reconnect the battery or fit a new battery if it was established that the battery was at fault (Refer to 414-01).
If the cooling fans operate during the above test, the large demand of current will overload the generator and cause the
engine to stall.
If the battery is in a low state of charge the voltage will rise momentarily when the battery is disconnected. However, the
maximum that the voltage can increase to with this new gene rator is 25V and then only for a maximum time of 200 mS.
Using a Substitute Battery
A substitute battery may be fitted for the tests. This batter y must be a known good example and must have been off-charge for at least twelve hours, with a term inal voltage of approximately 12.8V.
Ensure that all electrical loads are swit ched OFF and that the engine is cool.
Start the engine and allow to IDLE.
Measure the voltage across the battery term inals. It should have dropped a little due to the large start current and then
risen to a value of between 13V and 15V.
If the above test (whichever one used) indicates that the generator is not working then the connections on the rear face of
the generator should be checked. If there is a faulty connection, then the ge nerator will not perform correctly no matter
how fast it is driven.
Checking Generator Connections

ItemDescription
1Multi-Plug Connector
2B+ Main Output Terminal

CAUTION: The engine must not be running when multiplugs are connected or disconnected.
Check that the main B+ terminal is clean and tight.
Check that the IG terminal is clean and ma king good contact; if this connection is faulty, the generator will never function
correctly.
Disconnect the multi-plug at th e rear of the generator. With the engine not running and with the ignition switched on, use a
DMM to check for battery voltage between the centre pin on the multi-plug connector and a good vehicle ground. If the
measured voltage is correct, switch off the ignition and reconnect the multi-plug.
Multiplug Connector

If no voltage or low voltage is indicated, check for continuity of the harness between the multi-plug and Fuse 5 (10A) in the
Engine Compartment Fusebox - Left Hand Si de. Repair any damage to the harness if necessary. It should be noted that if
Fuse 5 has blown, the starter motor will not operate and the Engine Control Module will not receive an ignition supply.
Consequently, the engine will not st art, even with a slave battery.
Start the engine and test for correct ch arge or voltage level; check as described previously. If not charging and the
generator is being driven ie. no be lt slipping - renew the generator.


3Ground Stud for Suppression Module
4Heatsink for Voltage Regulator
ItemDescription
1Not Connected
2IG - Ignition Supply to Generator
3WL - Output to Charge Warning Lamp

suppression module positive cable from the positive
terminal.
3. Where fitted, remove the nut which secures the
suppression module negati ve cable and disconnect
the cable from the generator. Reposition the
suppression module harness clear of the generator.

9. Remove the lower mounting bolt and reposition the harness
mounting bracket.

10. Remove the upper securing bolt and withdraw the generator
from the mounting bracket.

11. Carefully, manoeuvre the ge nerator forward towards the
radiator.
12. Change the position of the ge nerator and remove it upwards
between the engine and the radiator.

Installation


13. Move the spacing bush rearward s slightly in the generator
mounting bracket, to ease fitting the new generator.
1. Position a suitable length bolt through the bush, fit a
tubular spacer or socket spanner, fit a nut and
tighten the assembly to move the bush slightly.
Remove the nut, bolt and spacer.

1. Fit the generator to the engine.
1. From above, position th e generator and fit the upper
mounting bolt and nut, but do not fully tighten.

2. Fit the generator lower mounting.
1. From below, reposition an d align the harness clip to
the generator lower mounting.
2. Fit the lower mounting bolt and nut, tighten to 38-48
Nm.
3. Connect the harness.
1. Reposition the suppres sion module harness and
connect the negative cable to the generator negative
terminal. Fit and tighten the terminal nut.

Installation


15. Change the position of the ge nerator and remove it upwards
between the engine and the radiator.

16. Move the spacing bush rearward s slightly in the generator
mounting bracket, to ease fitting the new generator.
1. Position a suitable length bolt through the bush, fit a
tubular spacer or socket spanner, fit a nut and
tighten the assembly to move the bush slightly.
Remove the nut, bolt and spacer.

1. Fit the generator to the engine.
1. From above, position th e generator and fit the upper
mounting bolt and nut, but do not fully tighten.
2. Fit the generator lower mounting.
1. From below, reposition an d align the harness clip to
the generator lower mounting.

Exterior Lighting - Exterior Lighting
Description and Operation
A multi-function switch located on the left stalk of the steering column switch assembly permits selection of either parking
(side), headlamps, auto-headlamp or off. Selection of a particular mode provides the appropriate input to the body
processor module (BPM).
Where the auto headlamp function is incorporated, a light sensor in the interior rear view mirror monitors ambient light and
provides an input to the BPM. The BPM responds by switching the low beam headlamps on or off as appropriate for the
prevailing light conditions.
The front and rear fog lamp switch is located on the fascia outboard of the steering column.
Front Lamps

Headlamp assembly
Each headlamp assembly consists of tw o headlamp units. The dipped beam lamp unit is located outboard and the main
beam lamp unit located inboard also carries the front parking (side) lamp. Access for bulb replacement is from the engine
compartment.
ItemPart NumberDescription
1—Headlamp (dip beam)
2—Headlamp (main beam)
3—Front Parking (side) Lamp
4—Front Direction Indicator
5—Front Side Marker
6—Side Repeater Lamp
7—Fog Lamp

Module Communications Network - Communications Network
Description and Operation
Fuse Boxes and Relays (LH Steering)

Parts List
There are six fuse box assemblies per vehicle, five of which have conventional, replaceable fuses. The High Power Protection
Module does not have conventional fuses, it comprises three 250 Amp fusible links to protect the starting circuit (two
connected in parallel) and the battery positive supply to the other fuse boxes.
Wiring Harnesses
ItemPart NumberDescription
1—Engine and Transmission Cont rol Module Compartment Relays (RH Steering opposite)
2—Front Firewall Relays
3—Front Seat Relays - Right Hand Side
4—Heelboard - Right Hand Side
5—High Power Protection Module
6—Trunk Fuse Box
7—Heelboard - Left Hand Side
8—Front Seat Relays - Left Hand Side
9—Engine Management Fuse Box
10—Engine Compartment Fuse Box
11—Engine Compartment Front Relays