1998 JAGUAR X308 ignition

Yes
R
EPAIR 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 U2
.
U2: CHECK T H
E MECHANICAL GUARD SENSE
CIRCUIT FOR SHORT TO HIGH VOLTAGE
Re
connect the battery negative terminal.
1
Turn the ignition swi
t
ch to the ON
position.
2
Measure t
he voltage between PI42, pin 01 (BY) and GROUND.
3
Is the volt

age greater than 10 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 U3
.
U3: CHECK T H
E MECHANICAL GUARD SE
NSE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swit
ch to the OFF
position.
1
Measure t
he resistance between PI42, pin 01 (BY) 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 U4
.
U4: CHECK THE MEC H
ANICAL GUARD SENSOR POWER SUPPLY CIRCUIT
Re
conn
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 5 volts?
Yes
REPAIR the power supply circuit. This circuit includ es the ECM. For additional information, refer to
the wiring diagrams. CLEAR the DTC. TE ST the system for normal operation.
No INSTALL a new mechanical guard sensor. CLEAR the DTC. TEST the system for normal operation.
PINPO
INT TEST V : DTC P1240, P1241, P1242
; SENSOR REFERENCE VOLTAGE MALFUNCTION,
HIGH/LOW VOLTAGE (THROTTLE SENSORS, FUEL TANK PRESSURE SENSOR)
TE S
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
V
1
: CHECK THE REFERENCE VOLTAGE AT TH
E APP SENSOR/MECHANICAL GUARD SENSOR
Disc
onnect the APP sensor electrical connector, PI42.
1
Turn the ignition swi
t
ch to the ON
position.
2
Measure the voltage between PI
42,
pin 04 (UW) and GROUND.
3
Is th
e volt
age less than 5 volts?
Yes GO to V2
.
No
GO to V3
.
V2
: CHECK THE APP SENSOR/MECHA
NICAL GUARD SENSOR REFERENCE VOLTAGE CIRCUIT FOR HIGH
RESISTANCE
Di sc
onnect the battery negative terminal.
1
D
i
sconnect the ECM electrical connectors, EM10 and EM11.
2
Me
asure
the resistance between PI42, pin 04 (UW) and EM10, pin 21 (UW).
3
Me
asure
the resistance between PI42, pin 04 (UW) and EM11, pin 08 (UW).
4
Is either resi
stance 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 V3
.
V3
: CHECK THE APP SENSOR/MECHA
NICAL GUARD SENSOR REFERENCE VOLTAGE CIRCUIT FOR SHORT TO
HIGH VOLTAGE

R
econnect the battery negative terminal.
1
Turn the ignition swi

tch to the ON
position.
2
Measure the
voltage between PI
42, pin 04 (UW) and GROUND.
3
Is th
e voltage greater than 6 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 V4
.
V
4: CHECK THE APP SENSOR/MECHA
NICAL GUARD SENSOR REFERENCE VOLTAGE CIRCUIT FOR SHORT TO
GROUND
Turn the ignition swi
tch to the
OFF position.
1
Meas
ure the resistance between PI42, pin 04 (UW) 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 V5
.
V
5: CHECK THE REFERENCE VOLTAGE AT THE THROTTLE POSITION SENSOR
Re

connect the ECM electrical connectors, EM10 and EM11.
1
Disc

onnect the TP sensor electrical connector, PI06.
2
Turn the ignition swi

tch to the ON
position.
3
Measure the
voltage between PI
06, pin 04 (UW) and GROUND.
4
Is th
e voltage less than 5 volts?
Yes GO to V6
.
No

GO to V7
.
V
6: CHECK THE THROTTLE POSITION SENSOR REFE
RENCE VOLTAGE CIRCUIT FOR HIGH RESISTANCE
Turn the ignition swi
tch to the OFF
position.
1
D
isconnect the ECM electrical connectors, EM10 and EM11.
2
Me

asure the resistance between PI06, pin 04 (UW) and EM10, pin 21 (UW).
3
Me

asure the resistance between PI06, pin 04 (UW) and EM11, pin 08 (UW).
4
Is either resi

stance
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 V7
.
V
7: CHECK THE THROTTLE POSITION SENSOR REFERENCE VOLTAGE CIRCUIT FOR SHORT TO HIGH VOLTAGE
Turn the ignition swi

tch to the ON
position.
1
Measure the
voltage between PI
06, pin 04 (UW) and GROUND.
2
Is th
e voltage greater than 6 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 V8
.
V
8: CHECK THE THROTTLE POSITION SENSOR REFE
RENCE VOLTAGE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swi
tch to the OFF
position.
1
Meas
ure the resistance between PI06, pin 04 (UW) 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 V9
.
V
9: CHECK THE REFERENCE VOLTAGE AT THE FUEL TANK PRESSURE SENSOR
Di

sconnect the FTP sensor electrical connector, FP01.
1
Re

connect the ECM electrical connectors, EM10 and EM11.
2
Turn the ignition swi

tch to the ON
position.
3

Measure the voltage between FP 01
, pin 03 (UW) and GROUND.
4
Is th
e volt
age less than 5 volts?
Yes GO to V10
.
No
CHECK
for DTCs associated with
TP sensor, APP/mechanical guard sensor, or FTP sensor. INSTALL a
new sensor as indicated by the DTC. CLEAR the DTC. TEST the system for normal operation.
V
10: CHECK
THE FUEL TANK PRESSURE SENSOR
REFERENCE VOLTAGE CIRCUIT FOR HIGH RESISTANCE
Disc
onnect the battery negative terminal.
1
D
i
sconnect the ECM electrical connectors, EM10 and EM11.
2
Measure t

he resistance between FP01,
pin 03 (UW) and EM10, pin 21 (UW).
3
Measure t
he resistance between FP01,
pin 03 (UW) and EM11, pin 08 (UW).
4
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 GO to V11
.
V11: CHECK
THE FUEL TANK PRESSURE SENSOR REFE
RENCE VOLTAGE CIRCUIT FOR SHORT TO HIGH VOLTAGE
Re
connect the battery negative terminal.
1
Turn the ignition swi
t
ch to the ON
position.
2
Measure the voltage between FP 01
, pin 03 (UW) and GROUND.
3
Is th
e volt
age greater than 6 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 V12
.
V12: CHECK
THE FUEL TANK PRESSURE SENSOR
REFERENCE VOLTAGE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swit
ch to the OFF
position.
1
Measure t
he resistance between
FP01, pin 03 (UW) 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 CHECK for DTCs associated with TP sensor, APP/mechanical guard sensor, or FTP sensor. INSTALL a
new sensor as indicated by the DTC. CLEAR the DTC. TEST the system for normal operation.
PI
NPOINT TEST W : DTC P1243; SENSOR RE
FERENCE GROUND MALFUNCTION (THROTTLE
SENSORS, FUEL TANK PRESSURE SENSOR, ECT, IAT, IAT 2 SENSORS)
TE S
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
W1: CHECK THE SENSO
R
REFERENCE
GROUND AT THE THROTTLE SENSORS
Disc
onne
ct the TP sensor electrical connector, PI06.
1
Meas
ure t
he resistance between PI06, pin 01 (BG) and GROUND.
2
Is th
e res
istance greater than 5 ohms?
Yes GO to W2
.
No
GO to W3
.
W2: CHECK TH
E THROTTLE SENSOR REFERENCE GROUND CIRCUIT FOR HIGH RESISTANCE
D
i
sconnect the ECM electrical connectors, EM10 and EM11.
1
Meas
ure t
he resistance between PI06,
pin 01 (BG) and EM10, pin 20 (BG).
2
Measure t
he resistance between PI06,
pin 01 (BG) and EM11, pin 12 (BG).
3
Is either resistance greater
than 5 ohms?
Yes REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. CLEAR the
DTC. TEST the system for normal operation.
No GO to W3
.
W3: CHECK THE SENSO R
REFERENCE GROUND AT
THE APP SENSOR/MECHANICAL GUARD SENSOR

P
INPOINT TEST Y : DTC P1260; SECURITY INPUT MALFUNCTION
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
Y1

: CHECK THE KTM TO ECM CIRCUIT FOR HIGH RESISTANCE
D

isconnect the ECM electrical connector, EM10.
1
D

isconnect the KTM electrical connector, FC22.
2
Me

asure the resistance between EM10, pin 06 (O) and FC22, pin 16 (O).
3
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 INSTALL a new KTM. CLEAR the DTC. TEST the system for normal operation.
PINPO
INT TEST Z : DTC P1474; INTERCOOLER COOLANT PUMP RELAY MALFUNCTION
•
NOTE: Early production vehicl
es have connector pin numbers that differ fro m the volume production pin numbers shown.
Use the wire color code for pin identifi cation on early production vehicles.
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
Z1

: CHECK THE INTERCOOLER PUMP RELAY TO ECM DRIVE CIRCUIT FOR HIGH RESISTANCE
Di

sconnect the battery negative terminal.
1
R

emove the intercooler pump relay.
2
D

isconnect the ECM electrical connector, EM13.
3
Meas

ure the resistance between the rela
y base, pin 01 and EM13, pin 10 (RY).
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 Z2
.
Z2
: CHECK THE INTERCOOLER PUMP RELAY TO EC
M DRIVE CIRCUIT FOR SHORT TO HIGH VOLTAGE
R
econnect the battery negative terminal.
1
Turn the ignition swi

tch to the ON
position.
2
Meas
ure the voltage between the
relay base, pin 01 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 Z3
.
Z3
: CHECK THE INTERCOOLER PUMP RELAY TO
ECM DRIVE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swi
tch to the OFF
position.
1
Meas
ure the resistance between th
e relay base, pin 01 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 Z4
.
Z4: CHECK THE INTER
COOLER PUMP RELAY GROUND CIRCUIT
Meas

ure the resistance between th
e relay base, pin 02 and GROUND.
1
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 INSTALL a new intercooler pump re lay. CLEAR the DTC. TEST the system for normal operation.
P
INPOINT TEST AA : DTC P1475; RADIATOR
FANS SLOW (SERIES) CIRCUIT MALFUNCTION
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS

AA1: CHECK THE RA
DIATOR FAN MODULE TO ECM
'SERIES' DRIVE CIRCUIT FOR HIGH RESISTANCE
Disc
onnect the battery negative terminal.
1
D
i
sconnect the ECM electrical connector, EM13.
2
Disc
onne
ct the fan module electrical connector, LS31.
3
Meas
ure t
he resistance between EM13, pin 15 (W) and LS31, pin 09 (W).
4
Is th
e 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 GO to AA2
.
AA2: CHECK THE RA
DIATOR FAN MODULE TO ECM 'SER
IES' DRIVE CIRCUIT FOR SHORT TO HIGH VOLTAGE
Re
connect the battery negative terminal.
1
Turn the ignition swit

ch to the
ON position.
2
Measure t
he voltage between EM13, pin 15 (W) and GROUND.
3
Is the 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 AA3
.
AA3: CHECK THE R A
DIATOR FAN MODULE TO ECM
'SERIES' DRIVE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swit
ch to the
OFF position.
1
Meas ure t
he resistance between EM13, pin 15 (W) 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 AA4
.
AA4:
CHECK THE RADIATOR FAN MODULE IGNITION SUPPLY
Reconn

ect the ECM electrical connector, EM13.
1
Turn the ignition swit

ch to the
ON position.
2
Measure the voltage between LS 31,
pin 08 (WP) and GROUND.
3
Is the vol
t
age greater than 10 volts?
Yes INSTALL a new radiator fan module. REFER to Section 303
-03
A Engine Cooling
/
303-03B Supercharger Cooli
ng
. CLEA
R the DTC. TEST the sy stem f
or normal operation.
No REPAIR the circuit. This circui t includes the EMS fuse box, (f use 14), the EMS relay, etc. For
additional information, refer to the wiring diagrams. CLEAR the DT C. TEST the system for normal
operation.
PINPOINT TE ST
AB : DTC P1476; RADIATOR
FANS FAST (PARALLEL) CIRCUIT MALFUNCTION
TES
T
CONDITIONS
D E
TAILS/RESULTS/ACTIONS
AB1
:
CHECK THE RADIATOR FAN MODULE TO ECM
'PARALLEL' DRIVE CIRCUIT FOR HIGH RESISTANCE
Disc
onnect the battery negative terminal.
1
D
i
sconnect the ECM electrical connector, EM13.
2
Disc
onne
ct the fan module electrical connector, LS31.
3
Meas
ure t
he resistance between EM13, pin 16 (WU) and LS31, pin 07 (WU).
4
Is th
e res
istance greater than 5 ohms?
Yes REPAIR the high resistance circuit. For additional information, refer to the wiring diagrams. CLEAR the
DTC. TEST the system for normal operation.
No GO to AA2
.
AB2:
CHECK THE RADIATOR FAN MODULE TO ECM 'PARALLEL' DRIVE 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
Measure t
he voltage between EM13, pin 16 (WU) 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 AB3
.
AB3
: CHECK THE RADIATOR FAN MODULE TO ECM
'PARALLEL' DRIVE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swi
tch to the OFF
position.
1
Meas
ure the resistance between EM13, pin 16 (WU) 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 AA4
.
AB4
: CHECK THE RADIATOR FAN MODULE IGNITION SUPPLY
Re

connect the ECM electrical connector, EM13.
1
Turn the ignition swi

tch to the ON
position.
2
Measure the
voltage between LS
31, pin 08 (WP) and GROUND.
3
Is the vol
tage greater than 10 volts?
Yes INSTALL a new radiator fan module. REFER to Section 303
-0
3A Engine Cooling
/
30
3
-03
B
Supercharger

Cooling
. CLEA
R the DTC. TEST the sy
stem for normal operation.
No REPAIR the circuit between LS31, pin 08 (WP) and battery. This circuit includes the EMS fuse box-
(fuse 14), the EMS relay, etc. For additional information, refer to the wiring diagrams. CLEAR the
DTC. TEST the system for normal operation.
P
INPOINT TEST AC : DTC P1516, P1517; GEAR
CHANGE PARK/NEUTRAL DRIVING MALFUNCTION
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
AC1: CH

ECK THE TRANSMISSION RANGE (TR) SE
NSOR TO ECM CIRCUIT FOR HIGH RESISTANCE
Di
sconnect the battery negative terminal.
1
Di

sconnect the TR sensor el
ectrical connector, EM47.
2
D
isconnect the ECM electrical connector, EM10.
3
Meas

ure the resistance between EM47, pin K (RU) and EM10, pin 15 (RU).
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 AC2
.
AC2: CH
ECK THE TRANSMISSION RANGE (TR)
SENSOR PARK/NEUTRAL SWITCHING ACTION
Meas
ure the resistance between pi
ns J and K of the TR sensor.
1
Mo
ve the selector lever from
PARK to NEUTRAL and back.
2
D
oes the resistance switch between open ci
rcuit and continuity as the lever moves?
Yes GO to AC3
.
No

INSTALL a new transmission range sensor. CLEAR th e DTC. TEST the system for normal operation.
AC3: CH
ECK THE D-4 SWITCH TO
TCM CIRCUIT FOR HIGH RESISTANCE
Di
sconnect the D-4 switch electrical connector, CC07.
1
Di

sconnect the TCM electrical connector, EM07.
2
Meas

ure the resistance between CC07,
pin 01 (US) and EM07, pin 13 (US).
3
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 INSTALL a new transmission range sensor. CLEAR th e DTC. TEST the system for normal operation.
P
INPOINT TEST AD : DTC P1606;
EMS CONTROL RELAY MALFUNCTION

E
lectronic Engine Controls - Engine
Control Module (ECM) Adaptation
Gen
eral Procedures
When to car

ry out adaptations
DTCs P1000/P1111 Conditions for adaptation
Fuelling Adaptations Drive Cycle
•
NOTE: Make sure the engine is at normal operating
temperature. (75°C, 167°F) 1.
Whenever the battery is disconnected, the Engine Control
Module (ECM) adaptations are reset to a "green" ECM
condition. In this condition, certain functions of the ECM are
inhibited, and the ECM must "r elearn" these functions. To
enable the ECM to do this, the vehicle will have to perform
some maneuvres which it may, or may not, do during a normal
road test. The routine in this pr ocedure should be carried out at
Pre-Delivery Inspection, and after any emissions related
rectification work involving the disconnection of the battery.
2. When the DTCs relating to a rectified concern are cleared,
P1000 (system checks not complete since last memory clear)
will be flagged. This DTC does no t indicate a failure, just that
diagnostic drive cycles need to be performed. The vehicle's on-
board diagnostic system will confirm that all the diagnostic
drive cycles are complete by flagging P1111, (system checks
complete since last memory clear)
1. Make sure these conditions are checked and corrected, if
necessary, before carrying ou t the adaptation procedure.
MechanicalElectrical
Engi
ne oil level correct
Coo

lant level correct
F

uel level greater than
30%, less than 80%
F
uel filler cap correctly
fitted/secure, seal in good condition
Al
l rectification work
relating to DTCs completed
F
uel, ignition and cooling
systems in good order
Al
l Diagnostic Trouble
Codes (DTCs) cleared
Al
l rectification work
relating to DTCs completed
F
uses
Harnes

ses
E

lectrical connectors

1.
Either
the Jaguar approved diagnostic system (where
available), or a scan tool should be connected to measure the
Mass Air Flow rate. Most generi c scan tools should be capable
of reading this parameter.
Depending on road conditions and dealer location, it may be
difficult to achieve the road sp eeds necessary to reach the air
flow indicated. It is possible to reach these air flow figures by
inducing a load on the vehicle, (making use of hills, using a
lower gear ratio, etc) or, if no alternative is possible, by
restraining the vehicle and re aching the air flow figure
Si
te
Mass Air Flow
(gra
ms/second)
D
riving Conditions
1Up t

o 7 g/s
Idle
in
P for 2 minutes
21
0 to 14 g/s
O
pen throttle in
P for 2 minutes
31
8 to 22 g/s
O
pen throttle in
P or D with
guidance * for 2 minutes
42
5 to 30 g/s
D
rive with guidance * for 2
minutes

2.2. Check on non-volatile diagnostic memory by wr iting a test pattern and then reading it back.
3. 3. Internal 'watchdog' hardware to check whether the TCM has crashed.
Transmission Control Module Supply Voltage
The TCM monitors battery and igni tion switched supply voltages.
A permanent supply is used to maintain a battery backed 'memor y'. Should this supply be cut, due to battery disconnection
perhaps, the 'adaptive shift' valu es will be lost. This will result in a small reduction in shift quality for a period until th e
adaptions are 're-learned'
The TCM will adopt 'limp home' mode as a result of the supply voltage being >16V or <7V with an engine speed >1600
rpm.
Should the ignition supply be >7V but <9V the TCM will hold the gear that it has currently selected. If after 2.5 seconds,
with the engine speed >1600 rpm, the voltage remains at this level, 'limp home' mode will be adopted. The 2.5 second
delay is built in to prevent reaction to a momentary voltage fluctuation.
Operation
CAUTION: Disconnection of the TCM and / or the vehicle batt ery will cause system adaptions to be lost; this may be
apparent by shift quality degradation. Fo llowing reconnection, a period of 'varied' driving will reinstate adaptions and thus
normal operation. Please ensure that the customer is made aware that the adaption period is variable and may occur after
handover, as the transmission re-learns the prevailing driving style.
• NOTE: Should the TCM fail, please ensure that the control housing cooling fan is operating correctly. Failure of the cooling
fan MUST be rectified before renewing the TCM and details of a fan fa ilure should accompany the returned TCM.
The TCM processes information received in both analogue and digital form, such as:
Transmission input speed Transmission output speed Throttle position Pedal demand Gear selector position Engine torque Engine speed Transmission oil temperature Mode switch
This information is then used by the TC M to control shift energy management and decide which shift program to implement
and which gear to select.
The TCM uses the various sensors and inpu ts to monitor the correct operation of the system an d is programmed to take
default action and inform the operator when a fault occurs.
Safety Functions
The safety functions are designed to safeguard against inappr opriate actions by the operator as well as against system
malfunctions. The system prevents reve rse gear from being engaged at high forward speeds and prevents manual
downshifting at excessive engine speeds; these functions are not operational in mechanical limp-home mode.
The TCM constantly monitors the transmissi on for faults. In the event of a problem the TCM will adopt a 'limp home' mode
in which only P R N D - (selector in D but only fourth gear is enabled) are available. The operator will be made aware of
certain faults by an in strument panel warning.
The electrical and diagnostic system has been designed such that system integrity is protected at all times, the safety
concept being based on th e following three points: