1994 JAGUAR XJ6 instrument panel

E I ect r ica I cl
Electrical schematic - Rapid Continuous MIL Lamp Flashing
a
0
0
10
I P20
1. Instrument Panel Fuse
586-1881
6. Passenger-side Air Bacr
7. RH tmpict Sensor 2. Engine Compartment Fuse 3. Safing Sensor 8. LH Impact Sensor
4. Cable Reel Cassettes 9. Air Bag MIL Lamp 5. Driver-side Air Bag 10. Diagnostic Module
-
Fig. 1
X300 EDM 15.1 - 47 Issue 1 August 1994

Electrical n
15.2 INSTRUMENTS
15.2.1 Introduction
The instrument pack is a self-contained, removable unit, which incorporates all the main display gauges and warning
indicators that are used to present vehicle condition information. The instrument pack is programmed during vehicle
build, to match the vehicle's individual requirements using 'Programmable Electronic Control Units System'
(PECUS). This is achieved via the diagnostic communication line, and therefore, should be renewed like-for-like. The primary
function of the instrument display is to provide the driver with information usual to normal driving requirements. The
secondary function is to display trip computer information.
The trip computer functions are selected via the steering column stalk switch
(LH). The messages are displayed in the
following order:
Odometer
- Distance - Range - Fuel Used -Average Fuel -Average Speed - Instant Fuel - Odometer (return).
Two trip computer switches, 'Reset' and 'Odo', are incorporated into the facia switch panel.
Instrument pack information is received from sensors positioned
at various locations about the vehicle (Fig. 1, follow-
ing page) via one of the two multi-pin sockets located at the rear of the instrument pack.
Information concerning vehicle condition and operation is displayed in one of three ways:
0 Information necessary to confirm normal vehicle operation: road speed, engine speed, oil pressure, battery
condition, fuel level, coolant temperature. This information is displayed using analogue gauges.
0 Information indicating the presence of a hazard/fault condition (low oil pressure/door open etc.) or operational
action (indicator flashing / headlamp full beam 'on' etc.). This information is provided by twenty two warning
lampsltell-tales, arranged in four groups; two groups of seven at the left and right sides of the instrument pack
and two groups of four
at the bottom of the instrument pack.
0 A Liquid Crystal Display (LCD) is located at the bottom-centre of the instrument pack and is normally used to
display the odometer reading, but it can also be used to display SRS fault conditions and trip computer informa-
tion such as vehicle speed, fuel usage and distance travelled.
0
X300 EDM 15.2 - 1 Issue 1 August 1994

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.
-&
60
eus KL
* \/ I I! I
I ~
I
I I
1
Ill I I '
Ill I I
I
w1
-2
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

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