1994 JAGUAR XJ6 Electrical Diagnostic Manual

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15.2.6 STATUS AND WARNING LAMPS
15.2.6.1 Transmission Sport Mode (green)
The transmission sport mode indicator is controlled by a signal from the Transmission Control Module (TCM). The
indicator is illuminated whenever 'Sport' mode is selected; a low signal is sent to the instrument pack (pin 14,48-way connector).
15.2.6.2 Traction Control OFF (green)
Two traction control lamps are provided: control fail and control off. Both lamps are controlled from one input from
the ABS I TC control module.
Under normal operating conditions, the input signal should be high.
If the input line is continuously low, traction con- trol has failed and both lamps will illuminate. If the input signal is a 4 Hz square wave the traction control system is
switched off, therefore the 'traction
off lamp will illuminate.
15.2.6.3
The operation of the direction indicator 'tell-tales' is controlled by the BPU. The 'tell-tales' are the only indicators on
the instrument pack which can be illuminated with the ignition OFF, for hazard warning.
The signal from the BPU to the instrument pack is pulsed, switching the direction indicators on and
off at the correct
frequency. The 'tell-tales'will illuminate when the signal is low. If the frequency doubles, this signifies that an exterior
direction indicator bulb has failed; the bulb failure warning lamp should also be illuminated.
The signal is fed to two separate inputs to the instrument pack, on the 48
-way connector; pin 40 for LH directional indi- cator 'tell-tale' and pin 41 for RH.
!We: If both direction indicator 'tell-tales' are permanently illuminated; this indicates that the BPU has not been
PECUS programmed. Check that a PECUS label is attached to the BPU.
Direction Indicators - LH & RH (green)
15.2.6.4 Main Beam (blue)
A low signal is supplied to the instrument pack (pin 24,48-way, connector) from the BPU when main beam is selected.
This illuminates the main beam 'tell-tail' indicator lamp.
Issue 1 August 1994 15.2 - 8 X300 EDM

15.2.7 FAULT DIAGNOSIS
15.2.7.1 Active High /Low Inputs
On certain inputs, ignition voltage is applied to the input via a 'pull-up' resistor inside the instrument pack (Fig. 1). This
supplies
a 'high' signal to the instrument pack input electronics. The signal can be pulled to ground by an external
component.
Active Low
This is where the component controlling the input to the instrument pack is normally in an open circuit condition, allow- ing the input to rise to the 'pull-up' voltage (ignition). When a function is required to be active (eg a warning lamp to
come on) the external component switches the input to a 'low' or ground condition, over-riding the 'pull-up'. The low
must be 1 volt or less, relative to the instrument pack's ground connection, to activate the function.
Active High
This is where the component controlling the input to the instrument pack is normally in a 'low' or ground condition,
over-riding the 'pull-up' voltage (ignition). When a function is required to be active (eg a warning lamp to come on)
the external component switches the input to
a 'high' or open circuit condition. The 'high' must be 5.0 volts or more,
relative to the instrument pack's ground connection, to activate the function. If the input is open circuit, the 'pull-up'
will raise the input voltage to ignition voltage and the resulting 'high' will activate the function.
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1
Speed Output 1 L .C 2 Speed Output 2
A Indicator Panel B Gauges
C LCDPanel
"C Temperature Output - A 1 CCM
Fig.
1 Instrument Pack Schematic Diagram
JEE-1838
Fault: Warning lamp / 'tell tale' does not illuminate when required
1.
2.
Switch ignition on and observe pack reset sequence. All lamps should illuminate. Renew any lamps which do not
illuminate.
If lamp still does not illuminate under the required conditions refer to Pin Point Tests for relevant circuit checks.
X300 EDM Issue 1 August 1994 15.2 - 9

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15.2.8 INSTRUMENT PACK PIN-POINT TESTS
15.2.8.1 Oil Pressure, Battery Condition, Coolant Temperature and Fuel Gauges
Gauge reads zero, full scale, too high or low
1.
2.
3. Oil
pressure and coolant gauges only; check relevant fluid level is within limits, top up if required and re-check
indication. If fluid levels are within limits on checking proceed to step 2.
Check connections to sensor are correct and secure. For battery gauge only check battery voltage is present at the
battery terminal posts.
Check resistance of sensor (if applicable) to ground, correct readings are as detailed in the following table:
Sensor title Resistance value
Oil pressure 3108 - 3308
Temperature
Fuel level 3461
(warm engine)
- 2418 (cold engine)
8061 (full tank) - 9008 (empty tank)
If resistance is out of range renew sensor.
If sensor resistance is proved correct, check the harness wiring continuity between the sensor and instrument pack
pin as detailed in the table below:
4.
I Sensor title I Instrument pack pin !
I Oil pressure I 21 (24-way connector) I Temperature I 19 (24-way connector) I
Fuel level 120 (24-way connector)
For battery condition gauge, checkvoltage between instrument pack 24
-way connector pins 2 and 4 is 13 f 2.5V. Refer to Section 15.5 for battery diagnostics.
If all previous checks prove correct remove and open the instrument pack. Examine flexi-circuit connections to
relevant gauge, ensuring correct and secure fitment.
Check continuity of flexi
-circuit tracks to gauge connections.
Check continuity of gauge driver windings by disconnecting gauge from flexi
-circuit and testing between the
upper central connection pin and each of the other two pins. If open circuit is recorded renew gauge.
5.
6.
7.
Gauge fluctuates
or gives erratic readings
1. Carry out steps 1 -4 above.
2.
Fit new sensor (where applicable) and re-check gauge.
3. Carry out steps 5
- 7 above
15.2.8.2 Speedometer
Gauge reads zero, full scale, too high or low
1.
2.
3.
4.
5. Refer
to Section 12,
ABS / Traction Control for fault diagnosis of wheel speed sensor.
Check harness wirin and connection from Instrument pack pin 15 (24
-way connector) and ABS /Traction Control
Control Module (AB!! /TC CM).
If all previous checks prove correct remove and open the instrument pack. Examine flexi
-circuit connections to
speedometer, ensuring correct and secure fitment.
Check continuity of flexi
-circuit tracks to speedometer connections.
Check continuity of speedometer driver windings by disconnecting from flexi
-circuit and testing between the
upper central connection pin and each of the other two pins. If open circuit is recorded renew speedometer.

6 15.2.8.3 Tachometer
Gauge reads zero, full scale, too high or low
1.
2.
3.
4.
5. Refer
to Section 5, Engine Management for fault diagnosis of tachometer signal.
Check harness wiring and connection from Instrument pack pin
24 (24-way connector) and Engine Management
Control Module (ECM).
If all previous checks prove correct remove and open the instrument pack. Examine flexi-circuit connections to
tachometer, ensuring correct and secure fitment.
Check continuity of flexi
-circuit tracks to tachometer connections.
Check continuity of speedometer driver windings by disconnecting from flexi
-circuit and testing between the
upper central connection pin and each of the other two pins, If open circuit is recorded renew tachometer.
15.2.8.4 Liquid Crystal Display
No (or patchy) illumination
1.
2. If no illumination check rear of instrument pack for attachment of 'PECUS' label. If label is not present then pack
will not have been programmed.
Check bulbs in rear of LCD module, renew as necessary.
Missing or Corrupt Segments
1. Switch ignition off, leave off for a minimum of 5 minutes, switch on and re-check panel display.
2. If display is still faulty remove instrument pack from vehicle and checkconnections between flexi-circuit and LCD
module.
15.2.8.5 Trip Computer
Inaccuracy
1. Check fuel sender, ABS /TC CM and ECM signals to instrument pack.
Issue 1 August 1994 X300 EDM 15.2 - 11

rl Electrical
15.2.8.6
1.
2.
3.
4.
Door I Pack pin connection I Switch connection
Driver 146,48-way I06
Door Open Warning lamp (Active low)
Close all four doors and turn ignition to ON.
Open each door in turn, checking that lamp illuminates.
On identification of non
-illumination, check continuity across suspect door switch, door closed -switch open cir- cuit, door open -switch short circuit.
If switch tests correctly check continuity from pack connector to the relevant door switch (see table below for pin
numbers).
I Passenger - front 147,4&way 118 I
Passenger - rear left 147,4&way I6L
Passenger - rear right I47,4&way I6R
(48 WAY) P4
(48 WAY) P4
1. Instrument pack
2. Driver’s door ajar switch 3. Passenger door ajar (front)
4.
5.
Passenger door ajar (RH rear)
Passenger door ajar
(LH rear)
1
Fia. 1 Door ODen Indication
J@6-1839

Electrical
15.2.8.7 fxhausf Temperafure Warning lamp (Active Low -Japan Only)
U: This lamp is present in all vehicle instrument packs but only Japanese market cars have the sensor circuitry
installed and connected. The lamp will be illuminated during instrument pack reset sequence
at each ignition
cycle.
1. Ensure harness wiring is intact from instrument pack pin 23 (48-way connector) to catalyst switching module and
from switching module to each thermocouple.
2. Check continuity across each thermocouple, renew if open circuit is recorded.
3. Measure voltage at pack pin
23,48-way connector, 0 volts indicates signal low ie lamp ON. A value of 12V at pin 15 indicates healthy signal, or no sensing circuitry fitted.
I 20
L
I WG
Exhaust temperature sensors
*+12V present only when ignition ON
'IS24
1. Instrument pack 20. Catalyst switching module
21. Thermocouple
J86-1900
Fig. 1 Exhaust Temperature
x300 EDM 15.2 - 13 Issue 1 August 1994

IT Electrical
15.2.8.8
1.
2.
luggage Compartment Warning lamp (active low)
Checkcontinuity across compartment latch switch. With trunklid open short circuit should be recorded, with trunk
lid closed open circuit should be recorded.
Measure voltage
at pack pin 16, &way connector, 0 volts indicates signal low ie lamp ON. Avalue of 12V at pin 16 indicates healthy signal.
(48 WAY) Pli
1
1. Instrument pack 6. Trunk lid ajar switch
J86-1840
Fig. 1 Luggage Compartment Warning Lamp

Electrical
15.2.8.9
1.
2.
Seat Self Warning Indicator (acfive low)
Check seat belt stalk switch for continuity across pins when belt is unlatched, when latched open should be re- corded. Ensure secure ground from switch pin ID
Measure voltage
at pack pin 15,48-way connector, 0 volts indicates signal low ie lamp ON. A value of 12V at pin
15 indicates healthy signal.
(48 WAY) Pl
I
I
I
1. Instrument pack
9. Body processor unit
20. Catalyst switching module
Fig. 1 Seat Belt Indication
X300 EDM 15.2 - 15 Issue 1 August 1994