
Automatic Transmission (V12) Powertrain 
Engine Speed 
The engine  speed is provided by  an open collector  signal supplied  from the engine  management  control module 
(ECM). 
Throttle Position 
This signal,  from the ECM,  performs the  following two functions: 
1. 
2. 
Engine  Torque  (and warm-up) 
This signal,  from the ECM,  performs the  following three functions: 
1.  During  cranking  to convey  the completion  of an  engine warm
-up  cycle  to TCM. 
2. To  convey engine  torque information,  under normal running  conditions, to TCM. 
3. To  convey engine  torque fault signals to TCM. 
Engine ‘warm
-up’  cycle commences  from ignition ON until 500ms after the engine  exceeds 400rpm. After this time 
delay  either  an engine torque,  or torque  fault signal  will be transmitted. 
Transmission Input Speed 
The  transmission  input speed sensor  is mounted  within the transmission housing  and produces a variable frequency 
signal,  directly  proportional  to forward  clutch housing rotational  speed which  is transmitted  to the  TCM.  Sensor resis- tance equals 1.25kQ f 0.25. 
Transmission  Output Speed 
The transmission  output speed sensor is mounted  within the transmission housing  and produces a variable frequency 
signal,  directly  proportional  to the  rear carrier  rotational speed which  is transmitted  to the  TCM.  Sensor resistance 
equals 
1.25w2 + 0.25. 
hake Application 
When a brake  application signal  is received, due  to brake  switch  operation,  the torque  convertor clutch  lock-up sole- noid  is de-energized,  releasing lock-up mode  if already  applied 
Transmission  Oil Temperature 
The  transmission oil temperature  sensor, located within the internal  harness,  monitors  oil temperature  and transmits a corresponding signal  to the  TCM. 
To convey  throttle position information  to the  TCM. 
To  indicate  fault conditions  between ECM and throttle  potentiometer. 
8.2.4.2 OUTPUTS 
Gear  Shift Solenoids 
The two  gear  shift solenoids, located  within the transmission  housing, determine  gear ratio  when  the selector  is in  any 
of the forward  gear positions. 
Force Motor 
The force  motor,  mounted within the transmission  housing acts as a transmission  torque fluid pressure regulator. 
Torque  Converter  Clutch (TCC) Solenoid 
The torque converter clutch  solenoid, mounted within the transmission  housing, provides a direct drive from the en- gine, via  the converter  clutch, to the driven  wheels, giving the  efficiency of a manual  gearbox.  The  solenoid also pro- vides a  ’ramp‘ apply and  release to engage / disengage  the clutch  gently. 
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X300 EDM Issue 1 August 1994 6  

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 
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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 
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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. 
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X300 EDM 15.2 - 1 Issue 1 August 1994  

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 
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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  

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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.