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

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Introduction87G
87G - 3V7 MR-372-J84-87G050$055.mif
UPC
Vdiag No.: 48, 4C
3. REMINDER
PROCEDURE
To run fault finding on the vehicle's computers, switch on the ignition in fault finding mode (forced + after ignition
feed). Run the self-test procedure for the UPC internal relays and fuses using AC016 Electrical supply circuit
test.
Depending on the type of vehicle equipment, proceed as follows:
To cut off the + after ignition feed, proceed as follows:
Faults
Faults are declared as either present or stored (depending on whether they appeared in a certain context and have
disappeared since, or whether they remain present but have not been diagnosed within the current context).
The present or stored status of faults should be taken into consideration when the diagnostic tool is used following
the + after ignition supply being switched on (without operating the system components).
For a present fault, apply the procedure described in the Interpretation of faults section.
For a stored fault, note the faults displayed and apply the instructions in the Notes section.
If the fault is confirmed when the instructions in the Notes section are applied, the fault is present. Deal with the fault
If the fault is not confirmed, check:
–the electrical lines which correspond to the fault,
–the connectors on these lines (corrosion, bent pins, etc.),
–the resistance of the component detected as faulty,
–the condition of the wires (melted or split insulation, wear). WARNING
Switch off all unnecessary consumers:
–Radio navigation system.
–Switch the passenger compartment ventilation speed to 0.
–Switch off the interior lights (forced off).
With the vehicle card in the card reader, press and hold the start button (+ 5 seconds) outside starting conditions,
connect the diagnostic tool and carry out the required operations.
Press the start button twice briefly (less than 3 seconds); check that the + after ignition feed has cut (computer
indicator lights on the instrument panel go out).

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 - 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-24V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF012
PRESENT
OR
STOREDALTERNATOR
1.DEF: Alternator mechanical or electrical fault
NOTESConditions for applying the fault finding procedure to present faults:
The fault is declared present after the engine has been running for at least 1 minute.
Special note:
The fault illuminates the Battery and STOP warning lights on the instrument panel.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
1.DEF
NOTESNone.
Check the fitting, condition and tension of the accessories drive belt.
Visually check that the alternator is not clogged.
Clean out the alternator cooling vents using an air gun.
Check the wiring, the connections and the earths (see Test no. 1 Wiring test).
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.
Run command AC014 Alternator regulation (see Interpretation of commands).
With the bonnet closed, start the engine.
Leave the engine to run for 2 minutes at idle speed.
If the fault is still present, 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.
USM_V48_DF012/USM_V4C_DF012

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of parameters87G
87G-73V7 MR-372-J84-87G050$660.mif
UPC
Vdiag No.: 48, 4C
PR008
BATTERY VOLTAGE AFTER REST
NOTESSpecial notes:
This value can only be interpreted after the engine and electrical consumers have been
stopped for at least 8 hours.
Apply if the Charge battery message is displayed on the instrument panel.
Recharge the battery (see Technical Note 6512A, Charging).
Check the battery (see 80A, Battery).
AFTER REPAIRRepeat the conformity check from the start.
USM_V48_PR008 /USM_V4C_PR008