Page 112 of 208
DIESEL EQUIPMENT
Injection warning light
13
OPERATING PRINCIPLE OF THE DIESEL INJECTION WARNING LIGHT ON THE INSTRUMENT PANEL
On switching on the ignition, the diesel injection fault warning light is illuminated. It extinguishes as the en-
gine begins to run.
•Fault in a component of the injection assembly
Faults in the following components may cause the warning light to illuminate :
- injector with sensor
- advance solenoid valve,
- engine speed sensor ,
- load lever potentiometer,
- pre-postheating (according to version).
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Page 113 of 208

DIESEL EQUIPMENT
Pre-postheating control
13
The pre-postheating function is controlled by the
computer, which controls the preheating plug re-
lay housing.
1) Ignition - Preheating
The preheating process is divided in two
phases :
a) Variable preheating
This is dependent on the coolant tempera-
ture, on the battery voltage and on alti-
tude (internal computer sensor) when the
ignition is switched on (the preheating
warning light illuminates).b) Fixed preheating
After the preheating warning light has
extinguished (variable preheating), the
plugs remain fed for 8 seconds before the
engine is started.
2) Starting the engine
During the action of the starter motor, the
four plugs are fed continuously.
3) Engine running - Postheating
The postheating also may be divided in two
phases:
a) Fixed postheating
After starting the engine, the plugs are
supplied simultaneously for a period of 10
seconds.
b) Variable postheating
Variable postheating begins when fixed
postheating ends. The time during which
the plugs are fed (continuously) depends
upon :
- the coolant temperature
- the engine speed ,
- the load (load potentiometer on pump
lever ).
Maximum preheating limit (battery vol-
tage lower than 9.3 volts and altitude hi-
gher than 2 000 m).
Minimum preheating limit (battery
voltage greater than 10.5 volts altitude
lower than 350 m).
13041S
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Page 114 of 208
DIESEL EQUIPMENT
Pre-postheating control
13
- 20 180time (s)
For an idle speed and load lever
position
Coolant temperature °C0204060
Variable postheating may be interrupted :
- permanently, if the coolant temperature is >
60°C,
- temporarily , if the unit receives full load
information for more than 3 seconds; the
function is established once again if the
engine returns to idle speed or low load,
- temporarily again if the battery voltage is
>16 V; the function is restored if Ubatt
< 15 V.
In all cases, the total duration of the postheating
function will never exceed 3 minutes.
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Page 117 of 208
DIESEL EQUIPMENT
Computer
13
PRM1316
CONNECTION
1-<-
2-----
3-----
4-->-
5-->-
6-->-
7-<--
8-<--
9-->-
10-<--
11-<--
12-<--
13-><-Computer supply
Computer earth
Sensor earth
Potentiometer lever supply
EGR solenoid control
Advance corrector control
Needle lift signal
Engine speed signal
Preheating warning light control
Fault finding information line L
AC status
Vehicle speed signal
Fault finding information line KPlug relay control
Altimetric corrector relay control
Fast idle speed control
Load lever position information
Fault finding warning light control
AC prevention control
Power assisted steering pump assembly
relay control
Engine speed information
Not used
Load lever signal
Air temperature signal
Coolant temperature signal14-->-
15-->-
16-->-
17-->-
18-->-
19-->-
20 -->-
21-----
22
23-<--
24-<--
25-<--
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Page 118 of 208

DIESEL EQUIPMENT
Defect modes
13
If there is a fault with one of the components listed below, the computer enters "defect mode", which means
that replacement values are used to ensure engine operation.
Faulty
componentSet values (for replacement)
Advance
corrector Pre-postheating
timeEGR function Fast idle speed AC function
Coolant sensorRunning time
functionPreheating : -
30°C
Postheating :
80°CCutRunning time
function-
Air sensorTemperature
= 22°C- Cut - -
Load
potentiometer100 % load lever
positionPostheating:
30 % load lever
position Cut - 20 % load lever
position
Altitude sensorAltitude
= 900 mAltitude
= 900 mCut - -
Battery
16 V < U < 6 VUbatt = 13.5V Not controlled - - -
TDC sensorMinimum
advance
Solenoid valve
fully open
position Postheating :
Not controlled
until ignition is
switched off
then on againCutSpeed
= 2 000 rpmSpeed
= 2 000 rpm
Needle lift
sensorDefect mode
advance
(Carto soft
F8Q 662)
Maximum
advance
(F8Q 630)----
Vehicle speed
sensor--Position :
V = 175 km/hPosition :
V = 175 km/hPosition :
V = 175 km/h
Heater plugs
relay housing- Cut - - -
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