1998 JAGUAR X308 body processor module

General Information - Terminology Glossary

Description an
d Operation

This glossary of terms is intended to cover emissions-related (to SAE J 1930) term inology, and other abbreviations that may
be used in this manual.
The required term may be looked-up in th e left-hand column, and subsequent columns give the standard acronym, unit or
abbreviation, and definition.
Te rm
(s)
Acr
ony
m /
Unit /
Abbreviation
De fi
nition
A
Accel
e
rator Pedal
AP
Af
ter Botto
m Dead
Center
ABDCEvent occurri ng after
BDC
Af
ter Top Dead CenterATDCEvent occurri ng after
TDC
Ai
rbag /
Supplementary
Restraint System
Airbag, SRSAi rbag restraint system for
dr
iver and front seat passenger
Air Cleane rACL
Air ConditioningA/C
Air Conditioning Con t
rol
Module
A/CCMModule c
ontrolling air conditioning, heating and ventilation
Air Conditioning SignalACSA
i
r conditioning compressor clutch operation is signalled to the ECM which
induces idle speed corrections to co mpensate for engine load changes
Alternating cu
rrent
ac
Ai
r Fuel R
atio
AFRN
omi
nally 14.7 parts air to one part fuel
Ampe
reASI unit of current
Ampere hourAhA current of one ampere
fl
owing for one hour
Anti-Lock Braking SystemABSS
y
stem which prevents wheel lock-up
under braking by sensing lack of
rotation of a wheel(s) and divertin g fluid pressure away from it (them)
ABS Control Mo
dule
ABS CM
ABS /
T
raction Control
Control Module
ABS / T
C CM
Atmosph
e
re
atmU
n
it of pressure (1.01325 bar)
Au
to
matic Stability
Control
ASCA form of vehicle
control
in which the ECM reduces en gine torque to control
wheel-spin
B
Baro me
tric Absolute
Pressure Sensor
BAR OSensor measuring the pressure of surr ou
nding air at any given temperature
and altitude
Bat t
ery positive voltage
B+The posi
ti
ve voltage from a battery or
any circuit connected directly to it
Before Bottom Dead
CenterBBDCEvent occurri ng before BD
C
Before Top Dead

Center
BTD
CEvent (usual ly
ignition) occurring before TDC
Blowe
rBLRDe
vice which supplies a current of air at
moderate pressure, e.g. heater or
A/C blower
Body Processor M
odule
BPMControl modu
le
for body electrical systems, e.g. interior lamps, windshield
wash / wipe control
Bott om D
ead Center
BD
CLowest poin t of piston
travel in a reciprocating engine
Brake hors
epowe
r
bhpEffecti
ve horsepower devel
oped by an
engine or motor, as measured by a
brake applied to its output shaft
Brake Mean Effective
Pres sureBME PThat p
art of the effective
pressure developed in a cyli nder that would result in
a cylinder output equal to the bhp of the engine
Brake On/ O
ff
BOOIn
dic
ates the position of the brake pedal
Br
it
ish Standard
BSStan
dar
d specification issued by the British Standards Institution
Br
it
ish Standard
Automotive
BSAu
BusTopology of a commu n
ication network
Bypass
AirBPAMechanica l
control of throttle bypass air
C
Camshaft Posit
i
on Sensor
CMPSIndi
cat
es camshaft position
Canadian Motor
V
ehicle
CMVSS

Safety Standard
Canister PurgeCANPControls pu
rging of the EVAP canister
Carbon dioxideCO2Colorless gas with

a density of a
pproximately 1.5 ti mes that of air
Carbon mon
oxide
COPoi
sonous gas produced as the re
sult of incomplete combustion
Case G
round
CSE GNDControl modu
le casing ground
Catal

ytic converter
In
-line exhaust system device used to reduce the level of engine exhaust
emissions
Ce
lsius
CSI ter
m for the Centigrade scale, with
freezing point at zero and boiling point
at 100°
Central
Processor Unit
CPUTh
e section of a computer that contai
ns the arithmetic, logic and control
circuits. It performs arithm etic operations, controls instruction processing, and
provides timing signals and other housekeeping operations
Cl
osed Loop
CL
Cl

osed Loop System
CLSControl
system with one
or more feedback loops
Col
umn/Mirror Control
Module
C/MC
M
Control ModuleCMA

self-contained group of electrical/electronic components, designed as a
single replaceable un it, and controlling one or more processes
Controll
er Area Network
CANA
communication system which allows control modules to be linked together
in a network.
Crankshaft Posi
tion
Sensor
CKPSGenerates crankshaft positi on informa
tion in conjunct
ion with the CKPTR (also
generates speed information in certain applications)
Crankshaft Posi
tion
Timing Ring
CKPT
R
Toothe
d ring which
triggers the CKPS
Crankcase Ventila
tion
System
CVSys
tem which scavenges camshaft cover and crankcase emissions and feeds
them into the inlet manifold
Cubic ce nt
imeter
cm
3
Curb weightWe

ight of vehicle with fuel, lubrican
ts and coolant, but excluding driver,
passengers or payload
D
Dat
a Link Connector
DLCConne
ctor providing access and/or control of the vehicle information,
operating conditions, and diagnostic information
De
gree
deg, °Angle or tempe
rature
D

epartment of
Transportation (US)
DO
T
D

epartment of Transport
(UK)
DTp
De
utsche In
stitut für
Normung
DINGerman stand
ards regulation body
Di

agnostic Module
DMSuppl
emental Restraint System (non-c
ontrolling) module for diagnostics
overview
Di
agnostic Test Mode
DTMA le
vel of capability in an OBD system.
May include different functional states
to observe signals, a base level to re ad DTCs, a monitor level which includes
information on signal levels, bi-directional control with on /off board aids, and
the ability to interface with remote diagnosis
Diagnostic Trouble CodeDTCAn al
pha/numeric identifier for a fault
condition identified by the On-Board
Diagnostic (OBD) system
D
ial test indicator
DTIA mechan
ical measuring
instrument, with a rotary indicating pointer
connected to a linear operating probe
D
ifferential pressure
Pressure di
fference betwee
n two regions e.g. between intake manifold and
atmospheric pressures
D
ifferential Pressure
Feedback EGR
DP
FE
An
EGR system that monito
rs differential EGR pressure across a remote orifice
to control EGR flow
D
irect current
dcCurrent which f
lows in on
e direction only, though it may have appreciable
pulsations in its magnitude
Du
al linear switch
DLSJ
-gate switch connected to the TCM on SC vehicles
E
EGR

Temperature EGRT
Sensor
EGRTSens
ing EGR function based on temperature change
EGR Vacu

um Regulator
EVRControls EGR
flow by changi
ng vacuum to the EGR valve
EGR Valve
Position
EVPAn EGR
system that direct
ly monitors EGR valve position to control EGR flow
Electrically E
rasable
Programmable Read-Only
Memory
EEP
ROM

Speed an
d load
Coo
l
ant temperature
Ti
me el
apsed from start up
Cl
osed l
oop fuelling
Determination of the vapour concentration is made by stepped opening of the EVAP valve and subsequent monitoring of the
fuelling correction. This function is performed prior to purging, so that at the onse t of purging the EVAP valve can be set to
the optimum position. Should the ECM be unable to determine the concentration before purging, a default value is
employed, which is then modified whilst purging is in progress.
When the purging process is operational th e ECM modifies the basic fuelling calculation to maintain the correct air / fuel
ratio.
Purging is inhibited during fuel cut-off and stability / traction control intervention.
Coolant Temperature Sen
sor
Th
e
sensor outputs a voltage to the ECM which decreases as temperature increases.
Cooling Fans


In response to engi
ne coolant temperat
u
re and climate control system demand, the ECM will energize the cooling fans.
Climate Control Compressor
The E
C
M will allow the compressor clutch to be engaged if th
e engine temperature and load demand are normal. Should the
driver require maximum engine powe r or the coolant temperature be high, the request will be denied.
Cranking Signal

The ECM reacts to a signal fr
om th
e Body Processor Module (BPM) when the starter motor relay is energi
zed. This signal is
used to trigger starting, fu el and ignition strategies.
Engine Speed and Cranksh
aft Position
Engine
speed and cran
k position are moni
tored by a sensor which is mounted on the cylinder block (flywheel housing)
behind the crankshaft drive plat e. It indicates rotational speed to the ECM in the form of 12 pulses per crank revolution.
Engine speed is used for synchronization of fuel an d ignition systems, as well as other functions.
Camshaft Position
The ca
mshaft position sensor is mounted at
the rear of Bank 2 cylinder head on the inlet side and provides one signal every
720 degrees of crankshaft rotation. The signal, in conjunction with the signal from the crankshaft position sensor, indicates
to the ECM that the piston of cylinder 1A is approaching TDC on the compression stroke.
Variable Valve
Timing (Where Fitted)
By energi
si
ng a solenoid to allow the pass
age of pressurized oil on each of the inle t camshaft drives, the ECM can vary by a
single stepped amount, the relati ve timing of the inlet valves.
Ign
ition
Ignit
i
on spark is produced by
individual on-plug coil units.
There are two ignition amplifiers; module #1 drives coils 1A, 2B, 3B and 4A, whilst module #2 drives coils 1B, 2A, 3A and
4B. The ECM controls the amplifiers.

The il
lustration above is a simplified expl
anation of how the starting system operates in conjunction with the Body Processor
Module (BPM) and the Engine Control Module (ECM).
Refer to the Starting Circuit Diagram in the Electrical Guide.
I g
nition Switch to ON Position
W
h
en the ignition key is set to the normal run position, the following sequence occurs:
The
is
olation relay in each fusebox is
energised to supply battery power to the fuses and associated circuits.
The BPM 'IGN
ON' terminal
is taken to 0V by the ignition switch.
The BPM
checks that various parameters are correct e.g. -
inertia switch is in the active condition - transmission is in
PARK - security system has been correctly disabled.
It e
m
De
scr
iption
1Batt
ery
2To Re ar
Fusebox
3Hi
gh Power Pr
otection Module
4To Front
Fu
seboxes
5Starter Re
lay
6Body Processor M
odule (BPM)
7Engine
C
ontrol Module (ECM)
8Ignition Switch
9CRANK Signal
10Ignition ON Signal
11Inertia Switch
12St
arte
r Motor and Solenoid
Starting System Operation

Starting System - Starting System
Diagn
osis and Testing
I
n
spection and Verification
W
A
RNING: Make sure
the vehicle is in NEUTRAL or PARK for vehicles with au tomatic transmission, NEUTRAL for
vehicles with manual transmissi on, and apply the parking brake. Failure to foll ow this instruction may result in personal
injury.
1. 1. Verify the customer concern.
2. 2. Visually inspect for obvious signs of mechanical or electrical damage, correct fitment, etc.
Vi
sual Inspection Chart
3.
3. If an obvi
ous cause for an observed or
reported concern is found, correct th e cause (if possible) before proceeding
to the next step.
4. 4. If the concern is not visually evident, refer to the Diagnostic trouble code (DTC) index.
CAUTION: When probing connectors to take measurements in the course of the pinpoint tests, use the adaptor kit,
part number 3548-1358-00. Failure to follow this in struction may result in damage to the vehicle.
• NOTE: When performing electrical voltag e or resistance tests, always use a digital multimeter (DMM) accurate to 3
decimal places, and with an up-t o-date calibration certificate. When testing resistance, always take the resistance of the
DMM leads into account.
• NOTE: Check and rectify basic faults before beginning diagnostic ro utines involving pinpoint tests.
Sym
ptom Chart
MechanicalElectrical
Starte
r motor
Flywheel

ring gear
Engine
s
eized
Batter
y condition, state of charge
Starte

r motor
F
u
se 3 of the EMS fuse box
High
power protec ti
on module
Starter relay Ignition switc
h

W
i
ring harness(es)
Damaged, loose or corroded connector
s

Body processor module (B
PM)

Engine
C
ontrol Module (ECM)
Sy
m
ptom
(
gene r
al)
Sy
m
ptom
(specific)
Possib l
e source
Acti
o
n
No
n
-Start
Engine does
not
crankEngine s
iezed
Batt
ery and
/or
cables
Inhibitor circuit St arte
r motor
Starter relay Ignition switc
h


ECM relay Body processor
modu le
Check that
the engine turns. Check the battery condition and state

of charge. For starter motor and ca ble tests,GO to Pinpoint Test A.
. For ECM relay
tests,
REFER to Section 303
-14
Electronic Engine Controls
.
Engine
c
ranks
too fast/slow
Batt ery and
/or
cables
St arte
r motor
Cy
linder
com
pression
Check the battery con
dition
and st
ate of charge. For starter motor
and cable tests,GO to Pinpoint Test A.
. Chec
k compressions.

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.

The In
strument Cluster is the primary electronic control module for the speedomete
r, tachometer, coolant temperature, fuel
level, driver information (Message Centre) and warning lamps.
The Instrument Cluster also:
- provides input / output informatio n signals for use by other modules.
- acts as a protocol converter (software language translator - the languages used on each network are very similar, but
neither can be directly interp reted by the opposite system) for communication between all modules on both the CAN and
SCP multiplexed networks. The Instrument Cluster is the only module on the vehicle which communicates between the two
networks.
Instrument Cluster Gauges

*Not used on all markets. Refer to the Drivers Handbook.
Although the gauges look like conventional analogue gauges, each pointer is driven by a stepper motor to provide more
12Ai
rbag Circuit Integrity
13Adaptive Damping
14Body Processor

Module
It

em
De
scription
1Low Fu

el Level
2Exhaus

t System Temperature *
3E

ngine Coolant High Temperature
4Di

rection Indicator Right Hand
5Side

/ Parking Lamps
6Handbrake ON / Low
Bra
ke Fluid Level
7Main

Beam
8Ai

rbag / Airbag System Fault
9Hi

gh Priority Text
Message Displayed
10M
essage Centre (Text Messages)
11Low Pri

ority Text Message Displayed
12Se

at Belt Not Fa
stened (Driver's)
13ABS Integrity
14EMS Fault
15D
irection Indicator Left Hand


accu

rate readings.
Refer to Section 413-08 for details of the Driver Information / Message Center.

Horn - Horn
Description and Operation
The horns, located behind the radiator gril le, each side of the radiator, are controlled by the Body Processor Module (BPM),
as described below.
The switch, located on the steering wheel pad, is operated, it signals the BPM to sound the horn. The BPM responds by
providing an earth from the horn-output to the horn relay coil. The relay contacts are subsequently closed and the horns
sound.
The horn operating relay, R6 is located in the engine compartm ent fusebox at the left hand side of the engine compartment.