2008 RENAULT SCENIC relay

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-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-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 - System operation87G
87G-11V7 MR-372-J84-87G050$110.mif
UPC
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 - System operation87G
87G-12V7 MR-372-J84-87G050$110.mif
UPC
Vdiag No.: 48, 4C
9 - Injection
The Protection and Switching Unit is involved in injection operation, relating to supplying the computer and its
sensors.
Supply malfunctions may lead to engine management customer complaints (rough idle, etc.).
10 - Fuse fault finding
The Protection and Switching Unit can detect the condition of its fuses and indicate faults using:
DF014 LEFT-HAND SIDE LIGHT CIRCUIT.
DF015 RIGHT-HAND SIDE LIGHT CIRCUIT.
DF016 LEFT-HAND DIPPED HEADLIGHT CIRCUIT.
DF017 RIGHT-HAND DIPPED HEADLIGHT CIRCUIT.
DF018 LEFT-HAND MAIN BEAM HEADLIGHT CIRCUIT.
DF019 RIGHT-HAND MAIN BEAM HEADLIGHT CIRCUIT.
DF020 FRONT FOG LIGHT CIRCUIT.
DF021 REVERSING LIGHT(S) CIRCUIT.
DF022 REAR SCREEN DE-ICER CIRCUIT.
DF023 FRONT WINDSCREEN WIPER CIRCUIT.
DF024 GAS COMPUTER SUPPLY.
DF025 AIRBAG/ELECTRIC POWER-ASSISTED STEERING SUPPLY.
DF026 AUTOMATIC TRANSMISSION SUPPLY.
DF029 STEERING COLUMN LOC/ENGINE MANAGEMENT SUPPLY.
DF030 AIR CONDITIONING COMPRESSOR SUPPLY CIRCUIT.
DF031 HEADLIGHT WASHERS SUPPLY CIRCUIT.
DF032 + 12 V RELAY SUPPLY CIRCUIT.
DF036 STEERING COLUMN LOCK SUPPLY CIRCUIT.
To carry out fault finding on the fuses, run command AC016 Test electrical supply circuits.
If a fuse is faulty, the associated fault becomes STORED.
Once the fuse has been replaced or the repair completed, run command AC016 Test electrical supply circuits
again to clear the fault.
Protection and Switching Unit Version
There are 4 Protection and Switching Unit versions:
–N1: vehicle with a 340 W fan assembly.
–N2: vehicle with a 460 W fan assembly.
–N3: vehicle with a 550 W fan assembly (external relay).
–N4: vehicle with 340 W, 460 W or 550 W fan assemblies + automatic transmission and/or LPG and/or with
headlight washers.

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Replacement of components87G
87G - 13V7 MR-372-J84-87G050$165.mif
UPC
Vdiag No.: 48, 4CENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Replacement of components
To remove and refit the UPC computer:
–Mégane (see MR 364, Mechanical, 87G, Engine compartment connection unit: Removal - Refitting).
–Scénic (see MR 370, Mechanical, 87G, Engine compartment connection unit: Removal - Refitting).
Once this operation is complete, run VP004 Vehicle parameters (see Configurations and programming).
Switch the ignition off and on again for the configurations to be recognised.
IMPORTANT
Removing or replacing the Protection and Switching Unit computer relays is forbidden.
MR-372-J84-87G050$165.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-23V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 4C
DF009
CONTINUED
Check the connection and condition of the passenger compartment fuse and relay box, the gear lever display,
the steering column top control module, the additional heater relay 1 and 2, the diagnostic socket, the
parking distance control ECU, the right and left-hand rear electric window switch, the radio, the electric
door mirror control, the front and rear electric window locking controls and the passenger electric window
switch, component codes 260, 1129, 1546, 1067, 1068, 225, 1222, 130, 131, 261, 134, 135, 1511, 1512
and 133.
Check for a voltage on connection AP43 to the connectors for the passenger compartment fuse and relay box,
the gear lever display, the steering column top control module, the additional heater relay 1 and 2, the
diagnostic socket, the parking distance control ECU, the right and left-hand rear electric window switch,
the radio, the electric door mirror control, the front and rear electric window locking controls, the
passenger electric window switch, component codes 260, 1129, 1546, 1067, 1068, 225, 1222, 130, 131, 261,
134, 135, 1511, 1512 and 133.
If the connection or connections are faulty and if 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 connections:
–AP31 between components 1337 and 997,
–AP11 between components 1337, 485, 155 and 1109,
–APCB between components 1337 and 645,
–AP15 between components 1337 and 1088,
–AP44 between components 1337, 756 and 1232,
–AP43 between components 1337, 260, 1129, 1546, 1067, 1068, 225, 1222, 130, 131, 261, 134, 135, 1511, 1512
and 133.
If the connections are faulty and if there is a repair procedure (see Technical Note 6015A, Electrical wiring
repair, Wiring: Precautions for repair), repair the wiring, otherwise replace it.
Check the connection and condition of 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.
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.