1998 JAGUAR X308 ECM

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.

Thi
s sensor uses a piezo-electric sensing element to detect kn
ock which may occur under acceleration at critical conditions.
Should detonation be present the ECM will retard ignition timing of individual cylinders.
Exhaust G
as Recirculation
The EGR
valve (where fitted) reduces NOx
emissions by recirculating a portion of the exhaust gases back into the inlet
manifold.
Heated Oxyg
en Sensors
The h
eated oxygen sensors, one per bank, are situated upstream of the catalysts. Integral
to the sensors are heaters
(under ECM control) which allow the sensor s to reach their operating temperature as soon as possible after engine start. A
comparison between the level of oxygen in the exhaust gas to that in the atmosphere produces an output signal. This signal
is used by the engine closed loop fuel strategy to make fuelling corrections and so control overall emission levels.
Oxygen Sensors

Thes
e sensors, one per bank, are situated downstream of the
catalyst. The comparison of upstream and downstream signals
allows determination of cata lyst conversion efficiency.




Knock Sensor

En
gine - Engine
D
iagnosis and Testing
Sym

ptom Chart
Sy
mptom Chart
Pinp

oint test A: P1392 (P1397)
VVT solenoid circuit low input
S
pecial Tool(s)

D

igital multimeter

Generi

c scan tool
Sy

mptom
Possib
le Sources
Acti
on
D

TC P1392 VVT solenoid A circuit low input
So
lenoid coil open circuit
Harness open circuit or blown fuse
Connector pins(s) bent , loose or corroded
*
*
*
GO to
P
inpoint Test A

*
D
TC P1397 VVT solenoid B circuit low input
So
lenoid coil open circuit
Harness open circuit or blown fuse
Connector pins(s) bent , loose or corroded
*
*
*
GO to
P
inpoint Test A

*
D
TC P1393 VVT solenoid A circuit high input
So
lenoid coil short circuit
Harness short circuit
Connector pins(s) bent , loose or corroded
*
*
*
GO to
P
inpoint Test B

*
D
TC P1398 VVT solenoid B circuit high input
So
lenoid coil short circuit
Harness short circuit
Connector pins(s) bent , loose or corroded
*
*
*
GO to
P
inpoint Test B

*
D
TC P1396 VVT solenoid B malfunction
O
il pressure failure
VVT solenoid sticking
Connector pins(s) bent , loose or corroded
Crankshaft position sensor failure
ECM failure
*
*
*
*
*
GO to
P
inpoint Test C

*
P
INPOINT TEST A : P1392 (P1397) VVT SOLENOID CIRCUIT LOW INPUT
•
NOTE: References in brac
kets are for Bank B (2)
T
EST CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1

: RETRIEVE DTCS
•

NOTE: Battery and or ECM disconnection prior to scanning wi
ll erase all data, ensure that the correct DTC is present.

Pin
point test B: P1393 (P1398) VVT solenoid circuit high input
W
ith EM014 disconnected, measure the resistance
between EM014/009 and ground EM016L
1
I
s the resistance < 0.5 OHM?
Yes Reconnect EM014, EM015, PI031 or (PI032)
GO to A6
No Inspect harness / connector EM014, ground stud and
splice EMS37 for corrosion, damage, bent or pushed back
pins and repair as required. Test the system for normal
operation.
A6
: END
Perform

appropriate service drive cycle and check for the
presence of DTC.
1
Has
the fault code cleared?
Yes STOP
No Contact Jaguar Service
P
INPOINT TEST B : P1393 (P1398) VVT SOLENOID CIRCUIT HIGH INPUT
•
NOTE: References in brac
kets are for Bank B (2)
T
EST CONDITIONS
D
ETAILS/RESULTS/ACTIONS
B1

: RETRIEVE DTCS
•

NOTE: Battery and or ECM disconnection prior to scanning wi
ll erase all data, ensure that the correct DTC is present.

Pinpoint test C: P1396
VVT solenoid malfunction
W
i
th EM015, EM014 PI031 and PI032 disconnected,
measure the insulation resistance between EM015/009
and EM015/008
1
I s
the resistance > 10 MOHM?
Yes Reconnect all connectors
GO to B7
No Inspect EM015 and PI031 (PI032) for corrosion, bent /
pushed back pins or locate and repair the harness /
connector PI001/016 (PI001/027). Test the system for
normal operation.
B7: EN
D
Perform
a
ppropriate service drive cycle and check for the
presence of DTC
1
Has th
e fault code cleared?
Yes STOP
No Contact Jaguar Service
PINPOINT TES
T C : P1396 VVT SOLENOID MALFUNCTION
T
E
ST CONDITIONS
D
E
TAILS/RESULTS/ACTIONS
C1
: RETRIEVE DTC
S
•
NOTE
: Battery and or ECM disconnection prior to scanning wi
ll erase all data, ensure that the correct DTC is present.

Whe r
e considered necessary, some hose conn
ections have an indication mark to ensure correct orientation of the hose when
being fitted.
All joints use spring-band clips, except small pipes on the bleed system joints - which use cobra clips. The heater feed and
return hoses use quick-connection unions.
Supply and return hoses for the heater are located between the cylinder banks.
A connection on the rear of the A-bank provides coolant supply for the electronic throttle and the EGR valve (where fitted).
The outlet from the electronic throttle connects to the return hose from the heater.
Cool
ant Header and Recovery Tanks
A recovery system comp
rising the header tank
and a recovery tank is fitted. The recove ry tank is located in front of the left
hand front wheel arch liner.
The header tank provides the cooling system filling point and carries the coolant level sensor. The pressure cap allows
controlled release of coolant to the re covery tank during normal operation.
The recovery tank accommodates the expansion of the system coolant during normal operation. On engine cool-down, the
coolant contracts and is returned to the main system.
Coo lin
g Fans
The two
rad
iator cooling fans are mounted in
a cowl assembly within the cooling module.
The fans are controlled by the ECM dependent on the demand fr om the cooling system (temperature) or the air conditioning
ItemDescrip
tion
1EGR
E
ngines
2Non
-
EGR Engines
3Hea
ter Connections

s
ystem (pressure).
Outputs from the ECM control the radiator fans control module, located behind the left hand side of the bumper, to operate
the fans in the series mode (slow), paralle l mode (Fast) or Off modes. Hysteresis in the temperature and pressure switching
values prevents 'hun ting' between modes.
Under hot operating conditions, the fans may continue to operat e for some time after the engine has been switched off, but
will stop automatically when the coolant te mperature has been sufficiently reduced.
Engine Coolant Temperature Sensor (ECT) and ECM

The engine coolant temperature (ECT) sensor is located in the coolant outlet pipe and reacts to engine coolant temperature
changes, providing an input to the Engine Control Module (ECM). The sensor has a negative te mperature coefficient so that
the sensor resistance decrea ses as temperature rises.
Temperature / Resistance Relationship Graph

T
emperature / Resistance
Relationship Table

Pinpoint test
A: P0116, P0125
Connector
loose or corroded
*
D
TC P0118 ECT circuit high input
Sensor short
Harness open circui

t
Harness short
Connector loose or corroded
*
*
*
*
GO to Pinpoint

Test C
*
D
TC P1474 Intercooler coolant pump relay malfunction
Intercooler pump relay
failure
Intercooler pump relay to ECM drive circuit
fault Intercooler pump relay coil ground circuit
fault Harness fault
Connector loose or corroded
Connector pins(s) bent or tracking between
connections ECM power supply fault
*
*
*
*
*
*
*
GO to Pinpoint

Test D
*
P
INPOINT TEST A : P0116, P0125
T
EST CONDITIONS
D
ETAILS/RESULTS/ACTIONS
A1

: RETRIEVE DTCS
•

NOTE: Battery and or ECM disconnection prior to scanning wi
ll erase all data, ensure that the correct DTC is present.
Conne
ct the scan tool
1
Have the DTC(s) and fr

eeze
frame data been recorded?
Yes GO to A2
A2: ENGINE
COOLANT SYSTEM CHECK
•

NOTE: Do not use the instrument display, if th
e ECT has failed this will not operate correctly.
Chec
k engine temperature rise using a thermocouple or
similar device.
1
Engine
temperature increasing?
Yes GO to A3
No Check coolant level
Check coolant for contamination
Check/test thermostat