ignition RENAULT MEGANE SCENIC 1995 Service User Guide

DIESEL EQUIPMENT
Pre-post-heating unit
13
DIAGRAM KEY
104Ignition switch
163Starter
171Air conditioning clutch
206Air conditioning trifunction pressure switch
247Instrument panel
251Bi-function coolant temperature switch
257Pre-heating unit
398EGR solenoid valve
412Fast idle solenoid valve (AC version)
597Engine fuse box
642AC / pre-heating separation diode
645Passenger compartment fuse box
680Pre-heating unit n° 1
681Pre-heating unit n° 2
682Pre-heating unit n° 3
683Pre-heating unit n° 4
711Diesel fuel pump
741Altimetric capsule
743Altimetric relay
777Power feed for fuse boxConnector (A)
+ Bat+ before ignition feed
Connector (B)
1Feed to heater plugs 1 and 3
2Feed to heater plugs 2 and 4
Connector (C)
A1 / S2Load dependence solenoid valve
control
A2 / PCLoad lever microswitch information
A3 / CTNCTN type sensor coolant temperature
information
B1/+APC+ after ignition feed
B2 / DEMStarter information
B3 / TemPre-heating warning light control (via
earth)
C1 / S1Not used
C2 / -Bat Earth
C3 / ClimFast idle solenoid valve control during
post-heating phase
92206-2R
IDENTIFICATION OF CONNECTORS
13-30

DIESEL EQUIPMENT
Pre-post-heating unit
13
PRINCIPLE OF OPERATION FOR GAS PRE-POST-
HEATING
1. "Pre-heating" when the ignition is turned on
a) Variable pre-heating
The time period during which the warning
light is illuminated and the heater plugs
are fed is dependent on the coolant
temperature.3. "Post-heating" while the engine is running
Post-heating has two phases:
a) Fixed post-heating
After the engine has been started, the
plugs are for for 10 seconds.
b) Variable post-heating
Variable post-heating begins when fixed
post-heating has ended.
During this phase, the plugs are fed
alternately 1 - 3 and 2 - 4 depending on
the coolant temperature.
If the coolant temperature sensor is faulty,
the heater plugs are fed systematically for
14 seconds.
b) Fixed pre-heating
After the pre-heating warning light has
extinguished (variable pre-heating), the
plugs remain fed for up to 8 seconds
before the engine is started.
2. Starting
The plugs remain fed while the starter is
activated.If the coolant temperature sensor is faulty,
the heater plugs are fed systematically for
30 seconds.
Variable post-heating may be
interrupted:
- finally when the coolant temperature
> 65°C,
- momentarily when the unit receives
full load information (post-heating
microswitch opens) for more than 1
second ; post-heating begins again
when the engine returns to idle speed
or low load (microswitch closes).
DI1304
DI1305
13-32

DIESEL EQUIPMENT
Pre-post-heating unit
13
FAULT FINDING
1. The pre-heating warning light does not operate
TEST SOLUTION
Earth the warning light output of connector (C) using
a 2 A fuse when the ignition is turned on (track B3).
• The fuse blows.
• The warning light does not illuminate.
• The warning light does illuminate.The warning light wiring in the instrument panel is in
short circuit. Repair the wiring.
The bulb is blown or the wiring is faulty.
Replace the bulb or repair the wiring.
Check:
- + battery on connector (A),
- + after ignition on connector (C),
- battery earth on connector (C).
If the feed is correct, replace the pre-post-heating
unit.
2. The pre-heating warning light only operates for a fraction of a second when the ignition is turned on.
TEST SOLUTION
Disconnect connector (B) and test the pre-heating:
• The warning light illuminates and there is a
voltage at the connector outputs (B).
• The warning light illuminates and there is no
voltage at the connector outputs (B).
• The pre-heating warning light illuminates for a
fraction of a second only.Check the plugs circuit. If it is correct, check and
replace the faulty plug(s).
Replace the pre-post-heating unit.
Check the before ignition feed to the pre-heating
unit.
13-33

DIESEL EQUIPMENT
Pre-post-heating unit
13
FAULT FINDING
3. There is no fast idle when engine is cold (with air conditioning option)
TEST SOLUTION
Run the air conditioning.
• The fast idle operates
• The fast idle does not operate.Check the connections at the pre-post-heating unit
(connector C).
Ensure continuity between track C3 of connector (C)
and track 1 on the solenoid valve.
Replace the pre-post-heating unit (ensure the
warning light operates correctly when the ignition is
turned on).
If the fast idle solenoid valve opens the pneumatic
circuit, repair the circuit between the vacuum pump,
the solenoid valve and the diaphragm.
If the solenoid valve does not open the circuit,
measure the voltage between the 2 tracks on the
solenoid valve connector.
•12 volts
Replace the solenoid valve after testing the
connections.
•0 volt
Ensure the following continuities :
- between track 2 on the connector and earth,
- between track 1 and track C3 of the pre-post-
heating unit.
13-34

DIESEL EQUIPMENT
Pre-post-heating unit
13
FAULT FINDING
4. Engine operation fault (difficulty in starting, idle speed unstable, noise...)
Check:
- the feed to the pre-post-heating unit :
•+before ignition at connector A.
•+after ignition on track B1 of connector C.
•earth on track C2 of connector C.
- at the pump connector, the resistance of the ALFB solenoid valve (between earth and track
A1) : 7Ω ± 0.5,
- the coherence of the temperature reading given by the coolant temperature sensor,
Temperature (°C) 25 80
Resistance (Ω) 2 610 to 2 990 310 to 350
- the adjustment and operation of the post-heating microswitch,
- the coherence of the open or closed status of the altimetric capsule switch according to the altimetric
pressure of the test site (the switch should be closed for a pressure > 925 ± 20 mbars).
If the fault persists carry out a complete re-adjustment of the pump.
13-35

ANTIPOLLUTION
Fuel vapour recirculation
14
CHECKING THE OPERATION OF THE CANISTER
BLEED VALVE
A malfunction in the system could cause the idle
speed to be unstable or the engine to stall.
Check the circuit conforms (see diagrams).
Take care to check that the pipe marked "CAN"
on the solenoid valve is connected to the canister.
Check the condition of the pipes up to the fuel
tank.
97393R4
1Inlet manifold
2Canister bleed solenoid valve
3Canister
4Fuel tankAt idle speed, check by connecting a pressure
gauge (- 3 ; +3 bars) (Mot. 1311-01) to the "CAN"
outlet on the solenoid valve, that there is no
vacuum (in the same manner, check the command
value read by the
XR25 using #23 remains at a
minimum X = 0.7 % for F3R and K7M engines). Is
there a vacuum ?
YESIgnition off, use a vacuum pump to apply a
vacuum of 500 mbars to the solenoid valve
at (C). The vacuum should not vary by more
than 10 mbars in 30 seconds.
Does the pressure vary?
YESThe solenoid valve is faulty, renew
it. Air must also be blown into the
pipe connecting the solenoid valve
to the canister to eliminate any
particles of active carbon.
NOThere is an electrical fault - check
the circuit.
NOUnder bleeding conditions (engine not at
idle speed, engine warm), there should be
an increase in the vacuum (at the same
time, the value for #23 on the XR25 should
increase forF3R and K7M engines).
The fuel tank breather pipe can also be checked.
After removing the filler cap, use a vacuum pump
to apply a vacuum to the pipe at (B). If a vacuum
can be applied to the pipe this shows that the
overfilling valve is correctly sealed.
As soon as the filler cap is replaced, however, the
vacuum should disappear quickly as the pipe is no
longer blocked and the internal degassing
chambers in the fuel tank are connected.
14-8

ANTIPOLLUTION
Exhaust gas recirculation (EGR)
14
K7M engine
OPERATING CONDITIONS FOR THE EGR SOLENOID
VALVE
The EGR system is operational if the following
conditions are met:
• coolant temperature greater than 20°C,
• air temperature greater than 5°C,
• no load position not recognised and throttle
position less than a set threshold, dependent
on engine speed (at 1024 rpm the throttle
position must be greater than 59 seen
using # 17 ;
at 5120 rpm the throttle position must be
greater than 103 seen using # 17),
• manifold vacuum greater than a certain
threshold.
The EGR solenoid valve is not operated if a fault is
detected with the :
- air temperature sensor,
- manifold pressure sensor,
- throttle potentiometer,
- EGR system.
A status bargraph on the XR25 visualises
operation of the EGR solenoid valve by the
computer.
It is however better to carry out a road test to
show this status. A test with the vehicle stationary,
engine operating under low loads is not
sufficient.
A faulty component in the EGR system will cause
an obvious worsening of the exhaust gas values.
CHECKING THE SEALING AND OPERATION OF THE
EGR SOLENOID VALVE
After the cooling fan has operated at least once,
stop the engine and turn the ignition off.
Disconnect the electrical connector.
Supply a 12 V feed directly to the solenoid valve.
Disconnect the pipe (D) connected to the vacuum
reservoir from the solenoid valve. In its place
connect a vacuum pump.
Create a vacuum of 300 mbars. The pressure
should not drop by more than 2 mbars per second
(120 mbars per minute).
Eliminate the vacuum to return the solenoid valve
to atmospheric pressure.
Run the engine at idle speed.
Create a vacuum of 300 mbars again, the engine
should run at idle speed, but unsteadily. If this is
not the case, replace the solenoid valve assembly.
Erase the computer memory after the operation.
14-16

ANTIPOLLUTION
Catalytic converter - oxygen sensor
14
CHECKS TO BE MADE BEFORE THE ANTI-
POLLUTION TEST
Ensure:
- the ignition system is operating correctly
(correct spark plugs, correctly set plug gap,
high voltage leads in good condition and
correctly connected).
- the injection system is operating correctly
(supply is correct - check using the XR25).
- the exhaust pipe is correct and is sealed.
- the EGR is operating correctly.
Check the vehicle history if possible (run out of
fuel, lack of power, use of incorrect fuel).
CHECKING ANTI-POLLUTION STANDARDS
Run the engine until the engine cooling fan has
operated twice.
Connect a correctly calibrated four gas analyser to
the exhaust tail pipe.
Keep the engine speed at 2500 rpm for
approximately 30 seconds then let the engine
return to idle speed and note the pollutant values.
CO
≤0.3 %
CO
2≥14.5 %
HC
≤100 ppm
0,97
≤λ≤1.03
1
NOTE : λ = ————
richness
λ>1→lean mixture
λ<1→rich mixture
If, after these tests, the values are correct, the
antipollution system is correct.
If the values are not correct, additional tests must
be carried out:
- Check the condition of the engine (condition
of the oil, valve clearances, timing, etc,...),
- Check the correct operation of the oxygen
sensor (see section 17) ,
- test for the presence of lead (see following
page).
If the test for the presence of lead is positive, en-
sure the vehicle uses two or three full tanks of un-
leaded fuel before replacing the oxygen sensor.
If, after all these tests have been carried out, the
values still do not conform, the catalytic converter
must be replaced. Petrol engine
14-21

STARTING - CHARGING
Alternator
16
OPERATION - FAULT FINDING
These vehicles are fitted with alternators with in-
ternal ventilation, an integral regulator and a
warning light on the instrument panel which ope-
rates as follows :
- when the ignition is turned on, the warning
light illuminates,
- when the engine starts, the warning light ex-
tinguishes,
- if the warning light illuminates again when
the engine is running, there is a "charging"
fault.
LOOKING FOR FAULTS
The warning light does not illuminate when the
ignition is turned on.
Check:
- the electrical connections are correct,
- the bulb is not blown (to do this, earth the cir-
cuit; the bulb should illuminate).
The warning light illuminates when the engine is
running
There is a charging fault which could be due to:
- the alternator drive belt being broken or the
charging cable being cut,
- internal damage to the alternator (rotor, sta-
tor, diodes or brushes),
- regulator fault,
- an excess voltage.The customer complains of a charging fault and
the warning light operates correctly.
If the regulated voltage is less than 13.5 V, check
the alternator. The fault could be caused by:
- a destroyed diode,
- a cut phase,
- track contamination or wear.
Checking the voltage
Connect a voltmeter across the battery terminals
and read the battery voltage.
Start the engine and increase the engine speed
until the voltmeter needle stabilises at the
regulated voltage.
This voltage should be between 13.5 V and 14.8 V.
Connect as many consumers as possible, the
regulated voltage should remains between 13.5 V
and 14.8 V.
IMPORTANT: if arc welding is carried out on the
vehicle, the battery and the regulator must be
disconnected.
16-2

STARTING - CHARGING
Alternator
16
OPTIMA 5800 diagnostic station
CHECKING THE CHARGING CIRCUIT USING THE DIAGNOSTIC STATION
The OPTIMA 5800 diagnostic station is used to test the alternator by measuring the voltage and current flow,
with and without electrical consumers.
NOTE : the ampermetric clamp on the station is of the inductive type (measuring range : 0 to 1000 A). It may
be positioned without disconnecting the battery, whichallows computers to retain their memory and set-
tings.
Depending on the engine, the ampermetric clamp may be positioned in different locations (the diagnostic
station will detect incorrect positioning) :
- F3R, F8Q engines : directly at the alternator output, the arrow on the clamp pointing towards the alterna-
tor.
- E7J, K7M engines : on the cable connecting the positive battery terminal to the alternator (this cable
crosses the battery compartment partition).
Measurements are made in three stages:
- measurement of battery voltage, ignition off,
- measurement with no consumers of the regulated voltage and current flow,
- measurement with the maximum number of consumers of the regulated voltage and current flow.
At the end of the test, the values noted will form the basis of a diagnostic report message:
- Battery voltage no load < 12.3 V = battery discharged.
Without consumers:
- Regulated voltage > 14.8 V = > regulator faulty,
- (Regulated voltage no load < 13.2 V) or (charging current < 2 A = > charging fault).
With consumers:
- Regulated voltage > 14.8 V = > regulator faulty,
- Regulated voltage < 12.7 V = > check the alternator flow with reference to its specifications:
Engine E7J K7M F3R F8Q
Without air conditioning 75 (45) 75 (50) 75 (50) 75 (50)
With air conditioning / 110 (80) 110 (80) 110 (80)
Notes for the table: - Current values in Amps.
- The value in brackets corresponds to the minimum flow which should be
supplied by the alternator when all consumers are connected.
FAULT FINDING
SPECIAL TOOLING REQUIRED
16-7