Alternator 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
UPC
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
Fault finding - System operation87G
87G-10V7 MR-372-J84-87G050$110.mif
UPC
Vdiag No.: 48, 4C
Only on vehicles with M9R injection:
The injection computer also acts on the alternator regulation voltage. The injection computer sends the maximum
authorised power delivered by the engine, to the UPC computer via the multiplex network. If the power from the engine
is less than the power consumed by the alternator, the UPC computer will reduce the alternator voltage.
For vehicles with any injection type except M9R:
The UPC sends the alternator charge to the injection to regulate the idling speed.
c) Starter
This turns the engine over to make it start, and requires a very powerful electric current, which the battery must be
able to supply.
The computer receives the starter activation request via the multiplex network from:
–injection,
–UCH,
–the automatic gearbox.
(see ET010 Starting conditions met)
The computer controls the starter relay.
In the event of a fault with the starter, refer to section 16A, Starting - Charging, Starter.
3 - Keyless vehicle
Under the keyless vehicle function, the Protection and Switching Unit is involved in the starting sub-function. The
computer:
–receives the supply request from the passenger compartment starter via the multiplex network, as well as the clutch
pedal position,
–controls the starter relay,
–inhibits or cuts out this relay control according to a signal prohibiting starting which is sent by the injection computer
or gearbox via the multiplex network (see 87B, Passenger compartment connection unit).
4 - Air conditioning
For the operation of the air conditioning and the role of the Protection and Switching Unit in the control of this
function (see 62A, Air conditioning).
Cold loop:
The computer receives the compressor switch-on request from the injection via the multiplex network.
The computer controls the compressor clutch engagement relay.
Heating:
The computer manages the alternator charge and sends back the signal over the multiplex network.
The computer also controls the rear screen de-icing.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Configurations and programming87G
87G-14V7 MR-372-J84-87G050$220.mif
UPC
Vdiag No.: 48, 4CENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Configurations and programming
This operation is used to configure the Protection and Switching Unit to the equipment present in the vehicle.
Procedure to follow for modifying these configurations:
●Establish dialogue with the UPC.
●Select the repair mode menu.
●Select the configure menu.
●Select line VP004 Vehicle parameters.
●Select the line corresponding to the vehicle equipment from the drop-down menus.
●Confirm the configurations selected and then click on validate.
●Switch the ignition off and then back on for the configurations to be recognised by the computer.
●In the configuration reading menu, check that each configuration has been performed.
Make sure that all the vehicle's equipment is working.Equipment required
CLIP diagnostic tool
Configuration Configuration reading Name of configuration
Automatic
(the alternator is
automatically recognised
by the Protection and
Switching Unit)LC001 Type of alternator
VP004 LC008 Gearbox type
VP004 LC007 Front fog lights
VP004 LC013 Headlight washers
MR-372-J84-87G050$220.mif

ENGINE COMPARTMENT CONNECTION UNIT
87G
87G - 15V7 MR-372-J84-87G050$275.mif
UPC
Vdiag No.: 48, 4CENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Fault summary table
Summary of faults on which fault finding can be performed by the Protection and Switching Unit.
(With corresponding design office codes).
Tool fault Associated DTC Diagnostic tool title
DF006 920E COMPUTER
DF007 9211 UPC - ALTERNATOR CONNECTION
DF009 9214 + AFTER IGNITION FEED CIRCUIT (Vdiag 4C only)
DF012 9210 ALTERNATOR
DF013 920F VOLTAGE REGULATION
DF014 9217 LEFT-HAND SIDE LIGHT CIRCUIT
DF015 9218 RIGHT-HAND SIDE LIGHT CIRCUIT
DF016 9215 LEFT-HAND DIPPED HEADLIGHT CIRCUIT
DF017 9216 RIGHT-HAND DIPPED HEADLIGHT CIRCUIT
DF018 921B LEFT-HAND MAIN BEAM HEADLIGHT CIRCUIT
DF019 921C RIGHT-HAND MAIN BEAM HEADLIGHT CIRCUIT
DF020 921D FRONT FOG LIGHT CIRCUIT
DF021 9226 REVERSING LIGHT(S) CIRCUIT
DF022 921E REAR SCREEN DE-ICER CIRCUIT
DF023 921A WINDSCREEN WIPER CIRCUIT
DF024 9222 GAS COMPUTER SUPPLY
DF025 9223 ELECTRIC POWER ASSISTED STEERING/AIRBAG
SUPPLY
DF026 9224 AUTOMATIC GEARBOX SUPPLY
DF027 9225 ACCESSORIES SUPPLY
DF029 9221 INJECTION/STEERING COLUMN LOCK SUPPLY
DF030 9219 CLIMATE CONTROL COMPRESSOR SUPPLY CIRCUIT
DF031 921F HEADLIGHT WASHER SUPPLY CIRCUIT
DF032 9227 +12 V RELAY SUPPLY CIRCUIT
DF033 9229 FAN ASSEMBLY SUPPLY CIRCUIT
DF034 9212 ALTERNATOR TYPE
DF035 9213 COMPUTER SUPPLY VOLTAGE
DF036 9220 STEERING COLUMN LOCK SUPPLY CIRCUIT
MR-372-J84-87G050$275.mif

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-17V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF007
PRESENT
OR
STOREDUPC - ALTERNATOR CONNECTION
CO: Open circuit
CC: Short circuit to earth
1.DEF: Communication disrupted
NOTESSpecial notes:
–Check the conformity of the wiring (see Test no. 2 Wiring test).
Repair if necessary.
–The fault illuminates the Battery charge warning light on the instrument panel and
the STOP warning light.
–Conditions for applying the fault finding procedure to stored faults:
The fault is declared present after the engine has been running for 10 minutes.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
CO
NOTES+ APC.
Engine stopped.
Disconnect the UPC-Alternator connection for the alternator component code 103.
Check the connection and condition of the alternator connector, component code 103.
If the connector is faulty and if there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Measure the voltage on connection 2N between the alternator, component code 103 and the battery earth,
component code 107.
If the voltage is less than 3 V
Check the connection and condition of connector MT1 for the Protection and Switching Unit, component code
1337.
If the connector is faulty and if 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:
–2N between components 1337 and 103.
If the connection is faulty and if there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring otherwise replace the wiring.
If the fault is still present, replace the Protection and Switching Unit (see Replacement of components).
AFTER REPAIRErase the faults from the computer memory, switch the + after ignition supply off and
back on again, and run another check using the diagnostic tool after 10 minutes
with the engine running.
USM_V48_DF007/USM_V4C_DF007

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-18V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF007
CONTINUED 1
If the voltage is greater than 9 V
Replace the Protection and Switching Unit (see Replacement of components).
If the voltage is greater than or equal to 3 V and less than or equal to 9 V
If the voltage is greater than or equal to 3 V and less than or equal to 9 V:
Use an oscilloscope to record the presence of a square pulse signal on connection 2N between the alternator,
component code 103 and the Protection and Switching Unit, component code 1337 on the alternator side.
Connect the oscilloscope between the connector of the UPC- alternator connection on the alternator side and the
battery earth, component code 107.
Adjust the oscilloscope:
–calibration: 2.5 V/div,
–time base: 2 ms/div.
AFTER REPAIRErase the faults from the computer memory, switch the + after ignition supply off and
back on again, and run another check using the diagnostic tool after 10 minutes
with the engine running.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-19V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF007
CONTINUED 2
Perform three successive acquisitions at intervals of 10 to 15 seconds.
Check that the signal resembles the image above.
If so:
Replace the alternator (see MR 364 or 370 Mechanical, 16A, Starting - Charging, Alternator: Removal -
Refitting).
Otherwise:
Contact Techline.
MULTIMETER
UNIVERSAL SCOPE
TIME BASE
2 ms/div
TRIGGER
AUTO
RANGE
2.5 V/div
AFTER REPAIRErase the faults from the computer memory, switch the + after ignition supply off and
back on again, and run another check using the diagnostic tool after 10 minutes
with the engine running.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-20V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF007
CONTINUED 3
1.DEF
NOTESNone.
Check the connection and condition of the alternator connector, component code 103.
If the connector is faulty and if 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 connection and condition of connector MT1 for the Protection and Switching Unit, component code
1337.
If the connector is faulty and if there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
With the engine running, switch on the electrical heated rear screen.
Measure the voltage between the earth of the alternator casing component code 103 and the battery earth
component code 107.
If the difference is over 1 V, check the vehicle earths.
If the fault is still present, contact the Techline.
AFTER REPAIRErase the faults from the computer memory, switch the + after ignition supply off and
back on again and run another check using the diagnostic tool.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-21V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF007
CONTINUED 4
CC
NOTESNone.
Check the connection and condition of the alternator connector, component code 103.
If the connector is faulty and if 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 connection and condition of connector MT1 for the Protection and Switching Unit, component code
1337.
If the connector is faulty and if there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the connector, otherwise replace the connector.
Disconnect the UPC-Alternator connection for the alternator and the Protection and Switching Unit.
Ensure that the UPC-Alternator connection is insulated in relation to the + 12V supply and the earth:
–2N between components 1337 and 103.
If the connection is faulty and if there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring otherwise replace the wiring.
If the fault is still present, disconnect the connector from the Protection and Switching Unit.
In + after ignition feed, measure the voltage of the connector MT1 for the Protection and Switching Unit on
connection code 2N.
If the voltage is less than 3V or greater than 9V:
Replace the Protection and Switching Unit (see Replacement of components).
If the voltage is between 3V and 9V:
Replace the alternator (see MR 364 or MR 370 Mechanical, 16A, Starting - Charging, Alternator: Removal -
Refitting).
AFTER REPAIRErase the faults from the computer memory, switch the + after ignition supply off and
back on again and run another check using the diagnostic tool.