1994 JAGUAR XJ6 warning light

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)
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

E I ect r ical
15.2.3 COMPONENT DESCRIPTION
15.2.3.1 Speedometer
The speed indication input signal, sent as a pulse rate, is generated by an open collectortransistor within the ABS con- trol module. The instrument pack converts the frequency of this signal to drive the speedometer and to provide two
road speed outputs:
Speed output
1 (pin 2,48 way connector)
This output is connected to the radio head unit, security control module and the power steering module.
Speed output 2 (pin
3,48 way connector)
This output is connected to the body processor unit, cruise control control module, air conditioning control module
and the engine management system.
15.2.3.2 Tachometer
The tachometer input, all engine variants, is provided by the engine management control module. When the engine
is running the control module generates three high state pulses per engine revolution.
15.2.3.3
This signal comes direct from the variable resistance type oil pressure sensor, mounted on the engine. The sensor
resistance values range from 75Q (8 Bar) to 330Q (0 Bar).
When the gauge reaches
a pre-determined reading the instrument pack illuminates the warning light.
Engine Oil Pressure and Warning lamp
15.2.3.4 Engine Coolant Temperature
This signal comes direct from the coolant temperature sensor (variable resistance type), mounted on the engine. The
sensor resistance values range from 34Q (hot) to 241Q (cold), when disconnected from the vehicle.
Note: The coolant temperature gauge is calibrated to indicate at approximately 'Normal' for a wide range of normal
engine operating temperatures.
15.2.3.5 Fuel Tank level Gauge and Warning lamp
This signal (pin 20,24-way connector) comes direct from the variable resistor type fuel level sensor. The sensor resis- tance values range from 80 ohms (full tank) to 900 ohms (empty tank).
When the gauge reaches a pre
-determined reading, the instrument pack illuminates the warning lamp.
15.2.3.6
Battery voltage is displayed on the gauge by measuring the ignition voltage.
The red charge warning lamp will illuminate if either the voltage is too low (below
10.5V) or too high (above 15.5V). In addition, the generator provides a low signal to the instrument pack (pin 9,48-way connector) when battery charging
is unsatisfactory.
Battery Voltage Gauge and Warning lamp
15.2.3.7 Liquid Crystal Display
A single line, six digit, 7 segment display with six trip function flags used for odometer, trip computer and driver mess- ages.
!Y,Q&: If the instrument pack has not been PECUS programmed, the back illumination of the LCD will not switch on.
Check that a PECUS label is attached to the back of the pack.
Issue 1 August 1994 15.2 - 4 X300 EDM