1998 JAGUAR X308 pedal

P1122Acce
lerator pedal position (APP)
sensor circuit 'A' low voltage
A
PP sensor to ECM sense circuit
'A' (sensor pin 5) open circuit or
high resistance
Sensor power su
pply fault
APP s

ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1123Acce
lerator pedal position (APP)
sensor circuit 'A' high voltage
A
PP sensor to ECM sense circuit
'A' (sensor pin 5) short circuit to
high voltage
APP s
ensor failure
For APP
sensor circuit tests, GO to
Pinpoint Test R.
, and G
O to Pinpoint
Test S.
.
P1221Acce
lerator pedal position (APP)
sensor circuit 'B'
range/performance
A
PP sensor to ECM sense circuit
'B' (sensor pin 3) open circuit,
short circuit or high resistance
Sensor power su
pply fault
Sensor r

eference ground fault
APP s

ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1222Acce
lerator pedal position (APP)
sensor circuit 'B' low voltage
A
PP sensor to ECM sense circuit
'B' (sensor pin 3) open circuit or
high resistance
Sensor power su
pply fault
APP s

ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1223Acce
lerator pedal position (APP)
sensor circuit 'B' high voltage
A
PP sensor to ECM sense circuit
'B' (sensor pin 3) short circuit to
high voltage
APP s
ensor failure
For APP
sensor circuit tests,GO to
Pinpoint Test R.
, andG
O to Pinpoint
Test S.
.
P1224Throttl
e control position error
Thro
ttle position adaptations not
performed after ba ttery disconnect
TP se
nsor disconnected
TP se

nsor to ECM sense circuits
open circuit, hi gh resistance
Throttl
e motor power relay failure
Throttl

e motor power relay to ECM
circuit fault
Throttl
e motor power relay power
supply open circuit
ECM ground circuit faul
t (relay coil
drive)
Th
rottle motor to ECM drive circuits

open circuit, short circuit, high
resistance
Throttl
e motor failure
Throttl

e assembly failure
Carry
out throttle adaptation
procedure. For TP sensor circuit
tests,GO to Pinpoint Test D.
, andG
O
to Pinpoint Test K.
. F
or throttle motor

circuit tests,GO to Pinpoint Test T.
.
F
or throttle body information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1226Mechanica

l guard sensor
range/performance
Mechanica
l guard sensor to ECM
sense circuit open circuit, short
circuit or high resistance
Sensor power su
pply fault
Sensor r

eference ground fault
Mechanica

l guard sensor failure
Mechanica

l guard actuator
seized/spring broken
For mech
anical guard circuit tests,GO
to Pinpoint Test U.
. F
or sensor power
supply circuit tests,GO to Pinpoint
Test V.
. F
or sensor ground circuit
tests,GO to Pinpoint Test W.
. For
throttle body i
nformation,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1227Mechanica

l guard sensor circuit
low voltage
Mechanica
l guard sensor to ECM
sense circuit open circuit or high
resistance
Sensor power su
pply fault
Mechanica

l guard sensor failure
For mech
anical guard circuit tests,GO
to Pinpoint Test U.
. F
or sensor power
supply circuit tests,GO to Pinpoint
Test V.
. F
or throttle body
information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1228Mechanica

l guard sensor circuit
high voltage
Mechanica
l guard sensor to ECM
sense circuit short circuit to high
voltage
Mechanica
l guard sensor failure
For mech
anical guard circuit tests,GO
to Pinpoint Test U.
. F
or throttle body
information,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.
P1229Throttl

e motor control circuit
mallfunction
Throttl
e motor disconnected
Th

rottle motor to ECM drive circuits

short circuit or open circuit
Throttl
e motor failure
Fo
r throttle motor circuit tests,GO to
Pinpoint Test T.
.
P1230Fue
l pump relay malfunction.
NOTE. This DTC covers the S/C
system fuel pump 1
F
uel pump relay failure
F

uel pump to ECM circuit fault
F

uel pump relay coil power supply
F
or fuel pump relay circuit tests,
REFER to Section 303
-04
Fuel
Charging and Con

trols
.

op
en circuit
ECM ground circuit faul
t (relay coil

drive)
P1235Vacuu m
switching valve (VSV) 1
circuit range/ performance
(mechanical guard position)
Vac u
um leak/blockage between the

throttle elbow and the throttle
vacuum actuator
Vacuu m
actuator failure
Mechanica
l
guard actuator
seized/spring broken
Carr y out mechanical checks
for
vacuum leak/blockag e, failed vacuum
actuator, and broken /siezed actuator
spring.
P1236Vacuu m
switching valve (VSV) 1
(vacuum) circuit failure
VSV 1 disconne cted

VSV 1 to ECM drive circu
i
t high
resistance, open circuit or short
circuit
VSV 1 powe r supply open
circuit
VSV 1 failu
r
e
For VSV tests,

REF
ER to Section 310
-03
Sp
eed
Control.
P1237Vacuu
m
switching valve (VSV) 2
(atmosphere) circuit failure
VSV 2 disconne cted

VSV 2 to ECM drive circu
i
t high
resistance, open circuit or short
circuit
VSV 2 power supply open
circuit
VSV 2 failu
r
e
For VSV tests,

REF
ER to Section 310
-03
Sp
eed
Control.
P1238Vacuu
m
switching valve (VSV) 3
(release) circuit failure
VSV 3 disconne cted

VSV 3 to ECM drive circu
i
t high
resistance, open circuit or short
circuit
VSV 3 powe r supply open
circuit
VSV 3 failu
r
e
For VSV tests,

REF
ER to Section 310
-03
Sp
eed
Control.
P1240Sensor r
e
fere
nce voltage
malfunction (throttle sensors, fuel
tank pressure se nsor) (ECM pins
EM10-21; EM11-8)
ECM t o
sensors reference voltage
short circuit to ground, short circuit
to high voltage, op en circuit, high
resistance
TP sensor , pedal position and
mechan
ical guard sensor(s), fuel
tank pressure sens or failure(s)
Fo
r sensor reference voltage circuit
tests,GO to Pinpoint Test V.
.
P1241Sensor re
ferenc
e voltage low
(throttle sensors, fuel tank
pressure sensor) (ECM pins EM10-
21; EM11-8)
ECM t o
sensors reference voltage
short circuit to ground
TP sensor , APP
and mechanical
guard sensor(s), fuel tank pressure
sensor failure(s)
F o
r sensor reference voltage circuit
tests,GO to Pinpoint Test V.
.
P1242Sensor re
ferenc
e voltage high
(throttle sensors, fuel tank
pressure sensor) (ECM pins EM10-
21; EM11-8)
ECM t o
sensors reference voltage
circuit open circuit, high resistance,
short circuit to high voltage
TP sensor , APP
and mechanical
guard sensor(s), fuel tank pressure
sensor failure(s)
F o
r sensor reference voltage circuit
tests,GO to Pinpoint Test V.
.
P1243Sensor re
ference ground
malfunction (throttle sensors, fuel
tank pressure sensor, ECT sensor,
IAT sensor, IAT sensor 2) (ECM
pins EM10-20; EM11-12)
ECM t o
sensors reference ground
circuit open circuit, high resistance
Throttle sensors, fuel
tank pressure

sensor, ECT sensor, IAT sensor,
IAT sensor 2 failures
F o
r sensor reference ground circuit
tests,GO to Pinpoint Test W.
.
P1245Engine crank signal low voltage Starter relay coi
l to ECM/BPM
circuit open circuit
For en gin
e crank circuit tests,GO to
Pinpoint Test X.
.
P1246Engine crank signal high voltage Starter relay coi
l to ECM/BPM
circuit short circuit to B+ voltage
B P
M failure
For en
gin
e crank circuit tests,GO to
Pinpoint Test X.
.
P1250Engine load
malfunction
Air in
take leak
Engine breath

er leak
TP sens

or circuit fault (DTC P0121)

Throttle
valve spring failure
Check air i
ntake system for leaks,
REFER to Section 303
-12
Intake Air
Distribution and Filterin

g
.
Check engi
ne breather system for
leaks,
REFER to Section 303
-08 En
gine
Emissi
on Control.
Se e
pinpoint test for P0121. For
throttle body information,
REFER to Section 303
-04 Fu
el
Charging and Con
t
rols
.
P1251Thr
o
ttle position malfunction
(engine off)
TP sensor to ECM wiri
ng open
circuit or high resistance
F o
r TP sensor circ
uit tests,GO to
Pinpoint Test D.
, andGO to Pinpoint

P3: CHECK
THE EMS SWITCHED
POWER SUPPLIES TO THE ECM
D
isconnect the ECM electrical connector, EM14.
1
Make sure the EMS re
lay i
s energized.
2
Meas

ure the voltage between EM10, pin 01 (WR) and GROUND.
3
Meas

ure the voltage between EM14, pin 03 (WR) and GROUND.
4
Are both

voltages greater than 10 volts?
Yes Contact Dealer technical support for advice on possible ECM failure.
No REPAIR the EMS switched power supply circuits. The su pply circuit to EM10, pin 01 includes fuse 18 of
the right-hand heelboard fuse box, the supply circuit to EM14, pin 03 includes fuse 01 of the trunk
fuse box. For additional information, refer to th e wiring diagrams. CLEAR the DTC. TEST the system
for normal operation.
PI
NPOINT TEST Q : DTC P1112, P1113; INTAKE
AIR TEMPERATURE (IAT) SENSOR #2 SENSE
CIRCUIT HIGH/LOW VOLTAGE
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
Q1:

CHECK IAT SENSOR 2 SENSE CIRCUIT FOR HIGH RESISTANCE
Di

sconnect the battery negative terminal.
1
Di

sconnect the IAT sensor 2 electrical connector, PI03.
2
D

isconnect the ECM electrical connector, EM12.
3
Me

asure the resistance between PI03, pin 02 (UP) and EM12, pin 07 (UP).
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 Q2
.
Q2: CH
ECK IAT SENSOR 2 SENSE CIRC
UIT 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
03, pin 02 (UP) 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 Q3
.
Q3:
CHECK IAT SENSOR 2 SENSE CIRCUIT FOR SHORT TO GROUND
Turn the ignition swi

tch to the OFF
position.
1
Meas
ure the resistance between PI03, pin 02 (UP) 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 INSTALL a new IAT sensor 2. CLEAR the DTC. TEST the system for normal operation.
P
INPOINT TEST R : DTC P1121, P1122, P1123;
ACCELERATOR PEDAL POSITION (APP) SENSOR
CIRCUIT "A" RANGE/PERFORMANCE, HIGH/LOW VOLTAGE
TE
ST
CONDITIONS
D
ETAILS/RESULTS/ACTIONS
R1: CHECK THE APP

SENSOR SENSE CIRCUIT FOR HIGH RESISTANCE
Di

sconnect the battery negative terminal.
1
D

isconnect the ECM electrical connector, EM11.
2
Di

sconnect the APP sensor electrical connector, PI42.
3
Meas

ure the resistance between EM11, pin 16 (K) and PI42, pin 05 (K).
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 DT
C. TEST the system for normal operation.
No GO to R2
.
R2: CHECK TH
E APP SENSOR SENSE 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
Me
asure the voltage between PI42, pin 05 (K) and GROUND.
3
Is th
e 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 R3
.
R3: CHECK THE APP SENSOR SENS
E CIRCUIT FOR SHORT TO GROUND
Turn the ignition swi
t
ch to the OFF
position.
1
Me
asure the resistance between PI42, pin 05 (K) 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 R4
.
R4: CHECK THE APP SENSOR COM
MON
REFERENCE VOLTAGE AT THE SENSOR
Reconn
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 4 volts?
Yes GO to R5
.
No
GO to R6
.
R5: CHECK THE APP SENSOR COM
M
ON REFERENCE VOLTAGE CIRCUIT
Turn the ignition swit
ch to the OFF
position.
1
Di
sconnect the ECM electrical connector, EM11.
2
Measure t

he resistance between EM11,
pin 08 (UW) and PI42, pin 04 (UW).
3
Is the 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 Check the ECM power supplies.
REFER to Electronic Engine Controls
in this
section.
R6: CHECK THE APP
SENSOR COM
MON REFERENCE GROUND
Meas
ure t
he resistance between PI42, pin 02 (BG) and GROUND.
1
Is th
e res
istance greater than 5 ohms?
Yes GO to R7
.
No
INST
ALL a new APP sensor. CLEAR the DTC.
TEST the system for normal operation.
R7: CHECK THE APP SENSOR COM
MON REFERENCE GROUND CIRCUIT
D
i
sconnect the ECM electrical connectors, EM10 and EM11.
1
Measure t

he resistance between EM10,
pin 20 (BG) and PI42, pin 02 (BG).
2
Measure t
he resistance between EM11,
pin 12 (BG) and PI42, pin 02 (BG).
3
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 Check the ECM GROUND circuits. If the GROUND circuits are sound, contact dealer technical
support for advice on possible ECM failure.
PINPO
INT TEST S : DTC P1221, P1222, P1223;
ACCELERATOR PEDAL POSITION (APP) SENSOR

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:

1.1. The hydraulic system has 'fail-safe' characteristics regardin g its electrical operation, such that should the power
supply be lost to the electro-hydraulic actuators the transmission will initiate a limp-home mode.
2. 2. Recognition of critical shift operation by monitoring the last element in the signal path, ie the solenoid valve, and
checking by means of redundant me asured variables, ie engine speed, input speed and output speed.
3. 3. Each time the vehicle is started there is a check on the entire safety hardware and the associated program parts
and signal paths. A malfunction in this part of the system, or triggering of the safety circuit, is communicated to
the operator through the illumination of the transmission warning lamp.
TCM Inputs
Input Speed Sensor (Torque Converter Turbine)
The input speed sensor provides the TCM with transmission inpu t shaft speed information. This signal is produced from an
inductive pick-up, generating 30 pulses per revolution.
Transmission Output Speed Sensor
The output speed sensor provides the TCM with transmission ou tput shaft speed information. This signal is produced from
an inductive pick-up, generati ng 36 pulses per revolution.
Transmission Oil Temperature Sensor
A thermistor which provides an electrical indication of the oi l temperature to the TCM. The signal is measured as a voltage
with reference to analog ue ground in the TCM.
Kickdown Switch (where fitted)
Kickdown is intended to provide maximum vehicle acceleration , via the appropriate downshift(s), when the operator uses
full throttle. A kickdown switch provides an electrical signal to the TCM wh en the accelerator pedal is fully pressed. The
switch is normally open, connected to vehicle ground. Should the switch fail the TCM will detect kickdown using the
accelerator pedal position.
Throttle Pedal Stop (where fitted)
This component, used where the kickdown switch is not fitted, limits throttle pedal travel .in the same way. The kickdown
feature is retained, but is controlled by throttle position only. The pedal stop must be set, using the PDU, in the same way
as the kickdown switch to optimize performance.
Mode Selection Switch
The mode selection switch is a two position switch indicati ng to the TCM the current performance mode selected by the
driver. The switch generates a tw o-bit digital input to the TCM.
Rotary Position Switch
The rotary position switch detects the position of the transmis sion selector shaft. The switch is supplied as part of a new
transmission assembly, mounted on the transmission body. The swit ch is used to indicate to the TCM the six positions of the shaft: Park, Reverse, Neutral, Drive, Third and Second. The switch provides a four-bit input to the TCM.
Drive to Fourth Switch
Detects the movement of the selector lever from Drive to Fourth position. The selector cable, and therefore the transmission selector shaft, does not move as the lever is operated between these two positions. The switch is located within the 'J-gate'
assembly, producing a digital output to indicate to the TCM that the lever has moved from D to 4 .
Serial Communications Interfaces

Controller Area Network (CAN)
The TCM is an integral part of the CAN system which facilitates the interchange of real-time data between control modules
and sensors. Please see section 303- 14 for a full description of CAN.
OBDII Interface
Data concerning OBDII related transmission failures is stored in the ECM for access via the J1962 socket.
System Functions
Range Selection
The selector lever is connected to the transmission via a bowden cable, which operates the transmission selector shaft
between all positions except Drive to 4 .
The TCM detects the gear selected by means of a rotary position switch fitted to the transmission selector shaft. A separate
Drive to 4 switch is located within the 'J' gate' assembly.
Movement of the selector lever between Park, Reverse, Neutral and Drive manually directs th e flow of transmission oil; the
TCM having control of the forward gears selected while the lever is in the Drive position.
Shift Point Selection
The gearshift points are selected, by the TCM, as a function of the output speed, engine load, selector position and shift
program selected. The operator has control over the shift points via the selector lever, throttle pedal movement, kickdown
function and mode switch.
'J' Gate Layout

Mode Switch
This switch allows the driver to select one of two base shift maps; Normal and Sport modes, the switch being illuminated
when Sport is selected.
Special Shift Programs
These specific condition shift maps are available to enhance the operation of the vehicle under specific driving conditions.
and are listed below in order of priority / title and operating condition.
1. 1. Traction: When traction intervention is active
2. 2. Hot mode: Extreme engine / transmission temperatures

CAN Input Signals
Traction status ABS malfunction ABS status Engine torque status Throttle position Accelerator pedal position Engine torque reduction confirmation Engine speed Engine coolant temperature Cruise status OBDII fault code clear request Throttle malfunction warning RED or AMBER All road wheel speeds Token for network status ECM Token for network status INST Token for network status ABS Diagnostic data in from external device (PDU)
Output Signals
Solenoid valve 1 <-> 2 and 4 <-> 5 shift Solenoid valve 2 <-> 3 shift Solenoid valve 3 <-> 4 shift Solenoid valve converter lock-up clutch Control valve - modulating pressure Control valve - shift pressure
CAN Output Signals
Engine torque reduction request MIL status (whether present DTC should operate MIL) Transmission input speed Transmission output speed Converter slip Kickdown status Gear position (actual) Gear position (selected) Gear selection fault Converter lock-up status Current selected shift map Transmission oil temperature Transmission malfunction Pecus flag (state of current TCM program) Target for next gear position Gear shift torque transfer progress at shift MIL status (response to activate the MIL relevant to a DTC) OBDII fault code clear acknowledgement Transmission DTCs (P codes) Token for network status TCM Diagnostic data out to external device (PDU)
Emergency Running (elect ronic limp-home mode)
The TCM constantly monitors the transmissi on for faults. In the event of a problem the TCM will adopt the limp-home mode, in which the gear currently held remains engaged, until P is selected. The modulati ng and shift pressures will increase to
maximum and converter lock-up will be inhibited.
Following the selection of P , the only ratios available will be 2 (irrespective of forward ratio manual selection) and R .
With the vehicle at rest, the procedure to manually select is as follows:
1. 1. Select P .