motor RENAULT SCENIC 2008 J84 / 2.G Engine Compartment Connection Unit Workshop Manual

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - System operation87G
87G-8V7 MR-372-J84-87G050$110.mif
UPC
Vdiag No.: 48, 4CENGINE COMPARTMENT CONNECTION UNIT
Fault finding - System operation
General operation
The Protection and Switching Unit is involved in the following functions:
–Access - Safety.
–Air conditioning.
–Lighting.
–Wipers.
–Charging circuit.
–Oil pressure detection.
–Electric power distribution.
1 - Electric power distribution
The main function of the Protection and Switching Unit is to switch and distribute the power supply to the vehicle's
systems, actuators or computers.
Part of this function is handled within the unit, but it is not electronically controlled by the computer.
+ 12 V battery feed
The Protection and Switching Unit receives energy from the battery via the Busbar and MM connectors (tracks 6 and
4) and redistributes the + 12 V feed.
+ 12 V after ignition
The UCH sends the Protection and Switching Unit the + 12 V after ignition feed request via the multiplex network.
When the Protection and Switching Unit receives this request, it actuates the after ignition relay unconditionally. The
signal is distributed to the sensors, actuators and computers.
2 - Charge circuit
One of the main functions of the Protection and Switching Unit is managing the charge circuit.
Purpose and components:
The main function of the charging circuit is to produce and distribute the electrical energy required to operate the
various electrical consumers on the vehicle (computers, lights, etc.).
It is also used to start the engine.
The main components are a battery, an alternator and a starter motor.
MR-372-J84-87G050$110.mif

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - System operation87G
87G-9V7 MR-372-J84-87G050$110.mif
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Vdiag No.: 48, 4C
a) Battery
The principal purpose of the battery is to provide the powerful current briefly required by the starter motor to start the
engine. For optimum starting, the current supplied by the battery must be sent to the starter motor with minimum
loss. To achieve this, the electrical connections (wires, terminals, connectors, etc.) must be in good condition.
When the engine is not running, the battery must feed the accessories that operate constantly, even with the ignition
switched off, such as the alarm, radio codes, computers, etc.
–PR004 Battery voltage represents the supply voltage of the Protection and Switching Unit.
–PR008 Battery voltage after rest represents the battery charge status. If PR008 is less than 12.1 V
(battery discharged) during the first few miles, a "Charge battery" message is displayed on the instrument panel.
The Protection and Switching Unit determines what the voltage across the battery terminals should be, based on the
battery charge status, the operating phase and the battery temperature.
To obtain this voltage, the Protection and Switching Unit actuates the alternator.
b) Alternator
The alternator only operates when the engine is running. Its function is to recharge the battery, and at the same time
to supply the electrical power required to operate all the electrical accessories on the vehicle.
The Protection and Switching Unit is linked to the alternator by a serial connection. The Protection and Switching
Unit and the alternator communicate via this connection.
Alternator management is therefore completely new in relation to previous Renault vehicles.
The Protection and Switching Unit intelligently manages the alternator regulation voltage according to the engine
phase, the battery charge and the temperature.
The alternator sends the Protection and Switching Unit the following signals:
–Type of alternator: the Protection and Switching Unit configures itself according to the alternator specifications.
The Protection and Switching Unit can detect electrical or communication faults on this connection and signal them
using fault DF007 UPC - Alternator connection.
When the battery charge and PR008 Battery voltage after rest decline, the Protection and Switching Unit can
temporarily increase the alternator voltage by 1 V for a duration of 30 minutes after starting.
Before the engine is started and during starting, the alternator voltage is fixed at 10.6 V.
A maximum of 30 seconds after the engine is started, the Protection and Switching Unit sets the alternator voltage
at the optimum calculated value.Note:
A battery must always be fully charged, even when stored.

ENGINE COMPARTMENT CONNECTION UNIT
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Vdiag No.: 48, 4C
5 - Exterior lighting
The Protection and Switching Unit receives lighting requests from the UCH via the multiplex network.
The computer then switches the power relays:
–side lights,
–dipped headlights,
–main beam headlights,
–front fog light.
For the operation of this function and the role of the Protection and Switching Unit in the control of this function,
(see 80D, Lighting).
6 - Wiping - Washing
The Protection and Switching Unit receives wiping requests from the UCH via the multiplex network.
The computer then switches the power relays:
–low or high-speed windscreen wiper,
–headlight washers pump relay.
–The Protection and Switching Unit also receives the windscreen wiper park position signal. Using this signal the
computer can determine whether the blade is jammed, and decide whether to stop the wiper motor to protect it.
For the operation of this function and the role of the Protection and Switching Unit in the control of this function,
(see 85A, W ipers-Washing).
7 - Oil pressure detection
The Protection and Switching Unit receives the oil pressure sensor signal and distributes it over the multiplex
network.
8 - Reverse gear engaged signal
The Protection and Switching Unit receives the reverse gear engaged position sensor signal and distributes it over
the multiplex network.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Conformity check87G
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Vdiag No.: 48, 4C
FUNCTION: AIR CONDITIONING
SUB-FUNCTION: COLD LOOP
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine stopped, + after ignition feed on.
FunctionParameter or Status
Check or ActionDisplay and Notes Fault finding
Compressor
controlAC008:Compressor
controlYou should be able to hear
the compressor clutch
(stops the motor running).In the event of a fault, apply the
procedure for dealing with
command AC008.
Fan assemblyAC009:Low-speed fan
assemblyThis command is used to
activate the fan assembly
at low speed.In the event of a fault, apply the
procedure for dealing with
command AC009.
AC010:High-speed fan
assemblyThis command is used to
activate the engine cooling
fan at high speed.In the event of a fault, apply the
procedure for dealing with
command AC010.
Low-speed
engine fan
assembly relay
controlET014:Low-speed
engine fan
assembly relay
controlINACTIVE
ACTIVEIn the event of a fault, consult
the interpretation for status
ET014.
High-speed
engine fan
assembly relay
controlET013:High-speed
engine fan
assembly relay
controlINACTIVE
ACTIVEIn the event of a fault, consult
the interpretation for status
ET013.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Conformity check87G
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Vdiag No.: 48, 4C
FUNCTION: WIPING
SUB-FUNCTION: WIPER POWER
NOTESOnly carry out this conformity check after a complete check with the diagnostic tool
(fault reading and configuration checks).
Application conditions: engine stopped, + after ignition feed on.
FunctionParameter or Status
Check or ActionDisplay and Notes Fault finding
WiperAC005:Low-speed
windscreen wiperThis command is used to
activate the windscreen
wiper motor at low
speed.In the event of a fault, apply the
procedure for dealing with
commands AC005 and AC006.
AC006:High-speed
windscreen wiperThis command is used to
activate the windscreen
wiper motor at high
speed.
Windscreen
wiper protectionET002:Windscreen
wiper protectionINACTIVEIn the event of a fault, refer to the
interpretation for status ET002.
Windscreen
wiper park
positionET018:Windscreen
wiper park
positionPRESENT (if the wiper
is not active)
ABSENTIn the event of a fault, refer to the
interpretation of status ET018.
Headlight
washerAC013:Headlight washer
relayThis command is used to
activate the headlight
washers relay on the
right and left-hand side
alternately.In the event of a fault, apply the
procedure for dealing with
command AC013.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of statuses87G
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Vdiag No.: 48, 4CENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of statuses
ET002
FRONT WIPER PROTECTION
NOTESSpecial notes:
Only apply the checks if the status is ACTIVE or BLOCKED.
If the status is ACTIVE, this indicates that after a wiping request, the Protection and
Switching Unit has detected abnormal operation for more than 6 seconds
(constrained or blocked).
If the status is BLOCKED, this means that the total duration of intermittent pauses is
greater than 2 minutes.
The status returns to INACTIVE as soon as the UCH requests another wiping setpoint
(wiper control adjusted, or request by the rain sensor).
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Make sure that nothing is mechanically blocking the movement of the wiper arms (blades stuck, condition and
assembly of the wiper mechanism linkage and that there are no objects that could impede the movement of the
mechanism).
Check that the wiper mechanism is not seized.
Repair if necessary.
Check the condition and connection of connectors CT1 and CN on the Protection and Switching Unit,
component code 1337.
If the connectors are faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check the condition and connection of the windscreen wiper motor connector, component code 212.
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check the insulation, continuity and the absence of interference resistance on the following connections:
–14M between components 1337 and 212,
–14L between components 1337 and 212,
–14K between components 1337 and 212.
If the connections are faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
If the fault is still present, contact the Techline.
AFTER REPAIRRepeat the conformity check from the start.
USM_V48_ET002 /USM_V4C_ET002
MR-372-J84-87G050$550.mif

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of commands87G
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Vdiag No.: 48, 4C
AC005
WINDSCREEN WIPER LOW SPEED
NOTESSpecial notes:
Check the condition and connection of fuse 9 (25A) on the Protection and Switching
Unit. Replace it if necessary.
Check that status ET002 Front wiper protection remains INACTIVE.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Check the condition and connection of the wiper motor component code 212 (tabs broken, bent or oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check for earth connection code MAS on the wiper motor component code 212.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check for + 12 V on connection code 14K on the wiper motor whilst running the command.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check the condition and connection of the Protection and Switching Unit CN connector, connection code 1337
(tabs broken, bent or oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check the insulation, continuity and the absence of interference resistance on the following connection:
–14K, between components 1337 and 212.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
If the fault is still present, contact Techline.
AFTER REPAIRRepeat the conformity check from the start.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of commands87G
87G - 81V7 MR-372-J84-87G050$770.mif
UPC
Vdiag No.: 48, 4C
AC006
WINDSCREEN WIPER HIGH SPEED
NOTESSpecial notes:
Check the condition and connection of fuse 9 (25A) on the Protection and Switching
Unit. Replace it if necessary.
Make sure that status ET002 Windscreen wiper protection remains INACTIVE.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Check the condition and connection of the wiper motor component code 212 (tabs broken, bent or oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check for earth connection code MAS on the wiper motor component code 212.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check for + 12 V on connection code 14L on the wiper motor whilst running the command.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check the condition and connection of the Protection and Switching Unit CN connector, connection code 1337
(tabs broken, bent or oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check the insulation, continuity and the absence of interference resistance on the following connection:
–14L, between components 1337 and 212.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
If the fault is still present, contact Techline.
AFTER REPAIRRepeat the conformity check from the start.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of commands87G
87G - 83V7 MR-372-J84-87G050$770.mif
UPC
Vdiag No.: 48, 4C
AC009
LOW-SPEED FAN ASSEMBLY
NOTESSpecial notes:
Make sure nothing is hindering the rotation of the blades.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Check the condition and connection of the fan assembly connector, component code 188 (tabs broken, bent or
oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check the condition and connection of the 6-track Protection and Switching Unit MM connector (tabs broken,
bent or oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check for earth, connection code M of the motor-driven fan assembly, component code 188.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check for + 12 V on the motor-driven fan assembly component code 188 when the command is running.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check the insulation, continuity and the absence of interference resistance on the following connection:
–49L, between components 1337 and 188.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
If the fault is still present, contact Techline.
AFTER REPAIRRepeat the conformity check from the start.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of commands87G
87G - 84V7 MR-372-J84-87G050$770.mif
UPC
Vdiag No.: 48, 4C
AC010
HIGH-SPEED FAN ASSEMBLY
NOTESSpecial notes:
Make sure nothing is hindering the rotation of the blades.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Check the condition and connection of the fan assembly connector, component code 188 (tabs broken, bent or
oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check the condition and connection of the 6-track Protection and Switching Unit MM connector (tabs broken,
bent or oxidised).
If the connector is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Check for earth, connection code M of the motor-driven fan assembly, component code 188.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check for + 12 V on the motor-driven fan assembly component code 188 when the command is running.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check the insulation, continuity and the absence of interference resistance on the following connection:
–49R, between components 1337 and 188.
If the connection is faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
If the fault is still present, contact Techline.
AFTER REPAIRRepeat the conformity check from the start.