Brakes (a)
12.3 COMPONENT DESCRlPTlONS
ABS / TC CM (3 Fig. 1)
The ABS / TC CM, located just below the hydraulic valve
block on the bulkhead, is the system controller and pro-
cesses all thevarious information supplied from the external
sensors and probes. The unit monitors ABS / TC operation
giving fault indication and disabling the systems when de- fects are detected. The unit is self testing and cannot be fault
diagnosed beyond 'black box' level i.e. faulty module. Sys-
tem fault codes are stored in a non-volatile memory for in- terrogation by external diagnostic equipment.
Solenoid Valves (2 Fig. 1)
The solenoid operated hydraulic valves, located within the
hydraulic module valve block, regulate the supply of pres- sure to the braking circuits allowing individual control of all wheels with a full ABS /TC system.
Nnfe: For ABS only, the driving (rear) wheels are con-
trolled by a common braking circuit.
The traction control system isolating valve has the
same characteristics as
a normally open valve. a
Hydraulic Pump /Motor Unit (1 Fig. 1)
This unit, located above the hydraulic valve block, ensures
that brake fluid is transmitted around the system at the cor- rect operating pressure. The 250W ds. motor draws 32A
current at peak operation and has an internal resistance of 0.m.
Wheel Speed Sensors (Fig. 2)
The four wheel speed sensors are identical in function and
construction. Wheel rotation creates the signal within the
sensor. This signal is supplied to the ABS /TC
CM where it provides wheel speed information. The sensor coil has a re- sistance value of 1.1 k Q and will have a voltage of 2.5V pres- ent on each connecting pin when the vehicle is stationary.
Throttle Flap Actuator Motor / Position Sensor (Fig. 3)
The throttle flap actuator motor, mounted adjacent tothe hy- draulic control unit, adjusts throttle position, irrespective of
accelerator pedal position, by regulating throttle opening
when traction control is demanded. The actuator motor
nominal 12V terminal voltage is supplied by ABS
/ TC CMduring normal operation. The motor has an internal re- sistance of approximately 1.6Q. The throttle position sensor
supplies information relative to the position of its centre tap
to the ABS
/ TC CM which regulates actuator movement.
The sensor has a resistance of 6.4 K!2. Aterminal voltage of 5V is supplied by ABS/TC CM to connection 3 during normal
operation,voltage between connections 1 and 2 will vary be- tween 0 and 5V dependant on wiper position.
Fig. 1
Fig. 2
Jrn 270
Fia. 3
X300 EDM 5 Issue 1 August 1994
Electrical IT
SECTION CONTENTS
Sub
-Section 15.2 lnsfrumenfs
Subsection Title SRO Page
15.2 ............. Instruments .................................................................... 15.2-1
15.2.1
............ Introduction .................................................................... 15.2-1
15.2.2
............ Instrument Pack Connectors - Pin Locations ......................................... 15.2-3
15.2.3
............ Component Description .......................................................... 15.24
15.2.3.1 .......... Speedometer ................................................................... 15.24
15.2.3.2 .......... Tachometer .................................................................... 15.24
15.2.3.3
.......... Engine Oil Pressure and Warning Lamp ............................................. 15.24
15.2.3.4 .......... Engine Coolant Temperature ...................................................... 15.24
15.2.3.5 .......... Fuel Tank Level Gauge and Warning Lamp .......................................... 15.24
15.2.3.6
.......... Battery Voltage Gauge and Warning Lamp .......................................... 15.24
15.2.3.7
.......... Liquid Crystal Display ........................................................... 15.24
15.2.3.8 .......... Trip Computer .................................................................. 15.2-5
15.2.4
............ Primary Warning Lamps (Illuminated Red) .......................................... 15.2-5
15.2.4.1
.......... Exhaust Temperature ............................................................ 15.2-5
15.2.4.2
.......... Low Oil Pressure ................................................................ 15.2-5
15.2.4.3
.......... Seat Belt ....................................................................... \
15.2-5
15.2.4.4
.......... Trunk Lid Open ................................................................. 15.2-5
15.2.4.5
.......... DoorAjar ...................................................................... 15.2-5
15.2.4.6
.......... Engine Coolant LeveL ............................................................ 15.24
15.2.4.7
.......... SRS Airbag Fault ................................................................ 15.24
15.2.4.8 .......... Charging Fault .................................................................. 15.24
15.2.4.9 .......... Brake System Fault .............................................................. 15.24
15.2.4.10 ......... Bark Brake ..................................................................... 15.24
15.2.5. ........... Secondary Warning Lamps (Illuminated Amber) ...................................... 15.2-7
15.2.5.1
.......... Transmission Fault ............................................................... 15.2-7
15.2.5.2
.......... Washer Fluid Level .............................................................. 15.2-7
15.2.5.3
.......... Bulb Fail ....................................................................... \
15.2-7
15.2.5.4
.......... Traction Control Fail ............................................................. 15.2-7
15.2.5.5
.......... Anti-lock Fail .................................................................. 15.2-7
15.2.5.6
.......... Low Fuel Level ................................................................. 15.2-7
15.2.5.7
.......... Check Engine ................................................................... 15.2-7
15.2.6.1
.......... Transmission Sport Mode ......................................................... 15.2-8
15.2.6.2
.......... Traction Control OFF ............................................................ 15.2-8
15.2.6.3
.......... Direction Indicators ............................................................. 15.2-8
15.2.6.4
.......... Main Beam .................................................................... 15.2-8
15.2.6
............ Status
and Warning Lamps ........................................................ 15.2-8
m
a
0
e
0
X300 EDM ii Issue 1 August 1994
Electrical IT
SECTION CON TENTS
Subsection 15.2 Instruments (continued)
Sub-Section Title SRO Page
15.2.7 ............ Fault Diagnosis ................................................................. 15.2-9
15.2.7.1
.......... Active High /Low Inputs ......................................................... 15.2-9
15.2.8.
........... Instrument Pack Pin-point Tests .................................................. 15.2-1 0
15.2.8.1 .......... Oil Pressure, Battery Condition, Coolant Temperature and Fuel Gauges ................. 15.2-1 0
75.2.8.2
.......... Speedometer .................................................................. 15.2-10
15.2.8.4
.......... Liquid Crystal Display .......................................................... 15.2-17
15.2.8.6
.......... Door Open Warning Lamp ...................................................... 15.2-12
15.2.8.7
.......... Exhaust Temperature Warning Lamp .............................................. 15.2-1 3
15.2.8.8 .......... Luggage Compartment Warning Lamp ............................................. 15.2-14
15.2.8.9
.......... Seat Belt Warning Indicator ...................................................... 15.2-1 5
15.2.8.3
.......... Tachometer ................................................................... 15.2-11
15.2.8.5
.......... Trip Computer ................................................................. 15.2-11
15.2.8.70
......... Park Brake Indicator ............................................................ 15.2-16
15.2.8.71
......... Main Beam Indicator ........................................................... 15.2-17
75.2.8.12
......... Direction Indicator Tell Tales ..................................................... 15.2-18
15.2.8.14
......... Washer Fluid Level Indicator ..................................................... 15.2-20
15.2.8.16
......... Brake Fluid Level Indicator ...................................................... 15.2-22
75.2.8.17
......... General Bulb Failure Indicator ................................................... 15.2-23
15.2.8.18
.........
75.2.8.19 .........
15.2.8.20 ......... Traction Control OFF Tell-tale .................................................... 15.2-24
0
75.2.8.13 ......... Generator IND Voltage Indicator ................................................. 15.2-19
7 5.2.8.15 ......... Engine Coolant Level indicator ................................................... 15.2-2 1
Transmission Sport mode Indicator ................................................ 75.2-24
Traction Control Failure Warning Lamp
............................................ 15.2-24
15.2.8.21
......... Anti-lock Failure Warning Lamp .................................................. 15.2-24
15.2.8.22
......... Check Engine Warning Lamp .................................................... 75.2-24
Issue 1 August 1994 iii X300 EDM
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
Electrical rl
JOS 1776
1. Instrument Pack 7. Powerwash Relay
2. Body Processor Unit
(BPU) 8. Washer Fluid Level Sensor
3. Oil Pressure Sensor 9. Brake Fluid Level Sensor
4. Coolant Level Sensor 10. Ignition Switch 5. Coolant Temperature Sensor 11. Column Switch
6. Coolant Recirculation Pump Relay 12. Fuel Tank Level Sensor
Fig. 1 Component Location Diagram
Electrical IT
15.2.2 INSTRUMENT PACK CONNECTORS
0
Socket A (24-way)
Pin Circuit Input
1. Fuel used 2. 12V ignition feed 3. Ground 4. Ground 5. Battery feed 6. 12V auxiliary feed 7. Anti-lock fail 8. -
Socket 6 (48-way)
Pin Circuit Input
1. - 2. Speed output 1
3. Speed output 2
4. Trip stalk cycle 5. - 6. - 7- 8. - 9. Generator indicator voltage 10. Brake fluid level 11. - 12. Trip reset 13. Screenwash fluid level 14. Transmission sport mode 15. Seat belt 16. Luggage compartment open
Pin
9.
10.
11.
12.
13.
14.
15.
16.
Pin
17.
18.
19. 20.
21.
22.
23.
24.
25.
26.
27.
28.
29.
30.
31.
32.
Circuit Input
Illumination feed
-
- -
Diagnostic serial output (K) Diagnostic serial input (L)
Distance
-
Circuit Input
Park brake (on)
D.I.
bulb fail - - -
Check engine
Exhaust temperature
Main beam
- - - - - - - -
Fig. 1 Pin Locations
Pin
17.
18.
19.
20.
21.
22.
23.
24.
Pin
33.
34. 35.
36.
37.
38.
39. 40.
41.
42.
43.
44.
45.
46.
47.
48.
Circuit Input
-
Coolant temperature
Fuel level
Oil pressure
Coolant temperature output
Tachometer
input - ECM
-
Circuit Input
Ground - trip keyboard
Traction control status
Trip clear
Coolant level
Side lights (on)
Left D.I. (on)
Right D.I. (on)
Trip
km / miles
General bulb fail
Transmission fail
Air bag fail
Door ajar
- Driver’s
Door ajar - Passenger’s
-
X300 EDM 15.2 - 3 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
15.2.3.8 Trip Computer
The instrument pack provides the trip computer functions, selected via the momentary stalk input and two action in- puts: 'Reset' and 'Odo'.
The signal used for each function are:
Distance:
Computed from the speed signal from the ABS control module.
Average Speed
Computed from the speed signal from the ABS control module.
Fuel Used
Computed from a pulsed signal from the engine management system.
Average Fuel Consumption
Computed from the speed signal and the fuel used signal.
Range
Computed from the speed signal, the fuel used signal and fuel level.
instantaneous Fuel
Computed from the speed signal and the fuel used signal.
15.2.4 PRIMARY WARNING LAMPS - ILLUMINATED RED
15.2.4.1 Exhaust Temperature (Japan only)
The exhaust temperature input (pin 23,48 way connector) is provided by the catalyst switching module (pin 6), which
pulls the line low when a fault occurs.
15.2.4.2 Low Oil Pressure
This signal comes direct from the variable resistance type oil pressure sensor. The sensor resistancevalues range from
7552 to 310Q.
15.2.4.3 Seat Selt
The seat belt input (pin 15,48 way connector) is provided by the seat belt stalk switch, via the body processor unit
(pin 26).
The seat belt lamp will illuminate when
a low signal is seen on the instrument pack input.
15.2.4.4 Trunk Lid Open
A microswitch located in the trunk lid lock provides a signal (pin 16,4&wayconnector) causing the trunk lid open indi- cator to illuminate whenever the trunk lid is opened or not closed correctly.
The trunk lid open indicator will illuminate when
a low signal is seen on the instrument pack input.
15.2.4.5 Door Ajar
Switches located in each door closing mechanism supply signals to indicate when any door is either open, or has not
been closed correctly. The system operates from two signals; an input from the driver's door (pin 46, 48-way con- nector) or a combined signal input from the passenger doors (pin 47,4&way connector).
The door ajar lamp will illuminate when
a low signal is detected on either of the two inputs.
X300 EDM 15.2 - 5 Issue 1 August 1994