1994 JAGUAR XJ6 Electrical Diagnostic Manual

w Automatic Transmission (AJ16)
SOL ENOlD VALVES
The following tests are performed continuously by a background task. If a fault is detected, it is filtered for a set period.
When filtering ends a fault code is stored in the TCM and action is taken to ensure the integrity of the system.
During limp home mode the internal relay is turned
off to remove the supply to the solenoids and the gearbox with default to fourth gear (if aforward gear is alreadyselected) and third gear (if P.R.N.). Selecting N and then D will engage
3rd gear only.
Each test checks that the feedback from the output stage module is consistent
with the driven state of the solenoid
output, detects short circuit to ground, short circuit to battery voltage and open circuit.
TORQUE CONVERTER CLUTCH SYSTEM - P 0743
PRESSURE CONTROL SOLENOID ELECTRICAL
- P 0748
SHIFTSOLENOID A ELECTRICAL - P 0753
SHIH SOLENOID B ELECTRICAL - P 0758
TCM TRANSMISSION
ccoo7/042 G B003/L
CC007l005 GBOOYH
ccoo7/024 GB003lK
CC007/006 GB003/B
CC007/0 19 G B003/M
TORQUE CONVERTER CLUTCH
SHIFT SOLENOID
A
SHIFT SOLENOID B
PRESSURE CONTROL SOLENOID
SOLENOID SUPPLY
Possible Causes:
. Faulty valve.
Faulty harness wiring /connectors.
Effects:
MIL illuminated.
. Transmission warning lamp illuminated.
Maximum fluid pressure applied.
Limp home mode applied.
Remedy:
Renew valve.
. Repair or renew harness I connector.
Issue 1 August 1994 14 X300 EDM

Automatic Transmission (AJ16) w
mnm
PnW%
wa Wn
1D Int
Fig. 1 Fault Codes PO743 I PO753 I PO758
171- I
1 1
1 L- 2
Fig. 2 Fault Code PO748
X300 EDM 15 Issue 1 August 1994

Automatic Transmission (AJ16)
TORQUE REDUCTION SIGNAL - P 1780
The diagnostic for this signal is based entirely on feedback from the ECM. If the torque reduction request is active for
greater than 2 seconds, the ECM starts the torque reduction fault timeout (IO seconds). If the signal returns to the
standby condition within this time, the timeout is reset. If the timeout matures then the ECM stores a fault code and
transmits 93% on the torque signal line and also lights the MIL where necessary.
The ECM will also initiate the torque reduction fault timeout
if the signal line is permanently high or low for greater
than 125ms. The conditions for resetting the timeout and the actions if the timeout matures are the same as previously
described above. When the TCM receives the correct indication on the torque signal line, this fault code will be stored
and
a substitute function will be adopted and the warning lamp will be illuminated. The engine management will send
normal torque signal when the torque reduction signal returns to standby or when the ignition is reset.
This torque reduction signal is used during gearshifts to conveythe actual amount of retard to be applied to the ignition
advance angle
afterthe other trims. The signal idles at 17% (or 12% if theTCM wishes to drive the MIL on), and changes
to 20% at the start of a gearshift. This represents 0" retard. When an amount of retard is required, the PWM will increase
to the desired value (between 20% and 90%) and return to 20% and then to idle state at the end of the shift.
TCM
PI HARNESS ECM
CC007/032 P1063/008 P1105/026
TORQUE SIGNAL MALFUNCTION - P 1781
The torque signal is a PWM signal from the ECM to the TCM which conveys information about the actual torque devel- oped by the engine in the range 0 to 510Nm. The base frequency is 91Hz and the signal which is active low should be
within the range 10% to 90% modulation. The torque signal is monitored continuously during initialization and oper
- ation. If the frequency of the signal is incorrect or the signal is out of range, then this fault code will be flagged. The
TCM will adopt a substitute function and the warning lamp will be illuminated. This fault code will only be flagged if the engine speed is above 448 rpm.
TCM
PI HARNESS ECM
CC007/02 1 P1063/007 PI 105/033
Possible causes:
. Faulty harness wiring I connector.
. Faulty signal from ECM.
Effects:
. Transmission warning lamp illuminated.
Substitute torque signal adopted by TCM.
. =Normal mode only available.
. No kickdown facility.
. Maximum fluid pressure applied.
Remedy:
. Repair or renew harness / connector.
Examine ECM fault diagnosis (refer to EDM, section 5.1).
Issue 1 August 1994 16 X300 EDM

Automatic Transmission (AJ16)
6
10
B
1
d8-1756
Fig. 1 Fault Codes PI780 / PI781
X300 EDM 17 Issue 1 August 1994

lw Automatic Transmission (AJ16)
TRACTION CONTROL INPUT ELECTRICAL - P 1782
The traction control input allows the ABS/TC CM, which performs the traction control function to inform theTCM when
traction control is in operation. This allows the TCM to select a specific shift pattern which increases the effectiveness
of the traction control.
The signal has two states; active and inactive. In the inactive state the line is pulled high by
a 1 k21 resistor in the TCM
and should rest at battery voltage. In the active state, the ABS /TC CM drives a square wave signal at 2.5 Hz ie on for 200ms, off for 200ms. During the off phase the voltage should be greater than battery voltage minus 1.5V and during
the on phase the voltage should be less than 1V.
Because traction control is not fitted to all vehicles the traction control input will be open circuit on some cars. Diagnos- tics are limited to detection of permanent short circuit to ground. Fault detection is triggered if the signal line voltage is less than 1.8V for longer than 200ms. If a fault is detected code P 1782 is stored and the traction control shift pattern
is inhibited. The diagnostic test is performed continuously during initialization and operation.
TCM ABS
/ TC CM
CC007/029 LS027/003 LHD
RS027/003 RHD
Possible causes:
Faulty harness wiring / connector.
. Faulty signal from ABS CM.
Effects:
. Traction control shift pattern disabled
Remedy:
Repair or renew harness / connector.
. Examine ABS /TC CM fault diagnosis (refer to EDM, section 12.1).
0
0
0
0
X300 EDM Issue 1 August 1994 18

0
0
Automatic Transmission (AJ16)
I
10
r
P29 7 I RP
'1 3
I
+12v T
n 1K21
1
I
r
n
J88-1791
Fig. 1 Fault Code PI782
X300 EDM 19 Issue 1 August 1994

w Automatic Transmission (AJ16)
TRANSMISSION WARNING LAMP - P 1785
The transmission warning indicator lamp is located in the instrument pack and is driven off by and active low signal
from the TCM. This means that if the TCM is not connected the warning lamp will be permanently illuminated.
This diagnostic runs continuously while in initialization and operation and will detect
a short circuit to battery or a short
circuit to ground on the input.
TCM
(CC007) BULKHEAD HARNESS (FC007) INSTRUMENT PACK (FCOOS)
PIN 16 -LAMP PIN 13 PIN 44
Possible causes:
Faulty wiring harness / connectors.
Faulty indicator lamp.
. Faulty instrument pack.
Effects:
. Permanent illumination of indicator lamp on instrument pack (if TCM or wiring faulty).
Remedy:
Repair or renew harness / connector.
Renew indicator lamp.
Examine instrument pack fault diagnosis (refer to EDM, section 15).
/I
b
M(t I
4r^
tl 1
11.1rn
Fig. 1 Fault Code P1785
Issue 1 August 1994 20 X300 EDM

Automatic Transmission (AJ16)
TP ELECTRICAL SIGNAL SYSTEM - P 1791
If the throttle angle signal line is held permanently high or low for more than looms, then this fault will be recognised
and stored. The TCM will adopt the substitute throttle value and turn on the warning lamp. The fault code will only be
stored if the engine speed is greater than 400rpm.
TCM PI HARNESS ECM
CC007/047 P1063/00 1 PI 1041032
Possible causes:
Faulty harness wiring I connection.
. Faulty ECM signal.
Effects:
Transmission warning lamp illuminated.
. MIL illuminated.
Normal mode only available.
Substitute throttle angle adopted.
No kickdown facility.
Remedy:
Repair or renew harness 1 connector.
Examine ECM fault diagnosis (refer to EDM, Section 5.1).
TP SIGNAL SYSTEM RANGE/ PERFORMANCE - P 1790
The throttle signal is a pulse width modulated (pwm) input which runs at a constant frequency of 183 Hz the information is contained in the duty cycle of the signal. If this information is out of range, that is, the duty cycle is less than 5% or
greater than 94%, then the TCM will use a substitute throttle value of 47% and will light the warning lamp and this fault code will be stored. During cranking, this signal is used to convey the engine coolant temperature. The coolant tem- perature signal persistsfor 500 msec after reaching the engine run threshold of 400 rpm. If theTCM does not recognise a valid throttle angle signal afterthis time then a substitute throttle value (47%) will be used and the warning lamp will
be
lit and this fault code will be stored. A fault code will only be stored if the engine speed is greater than 400 rpm. If an out of range coolant temperature is received then a substitute coolant temperature value (77" C) is used but no fault is stored.
X300 EDM 21 Issue 1 August 1994