2008 RENAULT SCENIC relay

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-7
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-7V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
General operation:
The UCH is involved in the following five functions (shared between several computers):
1/ Access-safety function
This function is divided into three sub-functions: Access, Protection and Starting.
2/ Air-conditioning function
This function is divided into three sub-functions, which are: User selection, Heating and Cold loop (see: 62A, Air
conditioning).
In this function, the UCH manages the triggering of the passenger compartment heating resistor control relays, as
well as the heated rear screen and air conditioning indicator lights.
3/ Wiping function
This function is divided into two sub-functions, which are: Wiper control and Wiper power.
4/ Lighting function
This function is divided into two sub-functions, which are: Lighting control and Lighting power.
5/ Tyre function
This function is divided into three sub-functions which are: Tyre reception, Tyre management and Tyre display.
MR-372-J84-87B000$086.mif
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-20
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-20V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
1.1.11 Special features of vehicle wiring (Mexico):
The glovebox locking/unlocking control is wired differently depending on the type of vehicle:
–Vehicle manufactured before 11/07/2005 for BCELJRK type:
1Passenger door, rear doors and boot opening control
2Passenger door, rear doors and boot closing control
3Glovebox motor
–Vehicle manufactured after 11/07/2005 for BCELJRK type:
1Driver's door and fuel filler flap closing control
2Driver's door and fuel filler flap opening control
3Glovebox motor
4Glovebox locking control relay
5Glovebox locking control

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-25
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-25V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
1.2.2 Unlocking/locking the steering column:
1Steering column lock
2multiplex line
3Supply
4Sensor Line
5Safety line
a/ Unlocking the steering column lock
Following authentication of the Renault card:
1/ The UCH sends a code to the electric steering column lock with an unlocking request via the multiplex network
(ET119 UCH request to steering column lock).
2/ If the electric steering column lock recognises the code, it unlocks and sends its unlocked status to the UCH
(ET073 Steering column lock sensor signal).
3/ When the UCH receives the "Steering column unlocking completed" signal, it orders the Protection and Switching
Unit to activate the + after ignition relay and the procedure continues.
The physical status of the column lock can be displayed by status ET072 Steering column lock and its
programming can be displayed by status ET071 Steering column lock blank.
The steering column lock remains locked if:
–There is excessive mechanical load on the steering column (e.g.: wheel jammed against a kerb),
–the battery voltage is too low,
–the power demanded by the column lock is too high (thermal protection of the column lock electric motor). Note:
After ignition feed can only be established if the steering column unlocking procedure is performed
correctly.

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-34
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-34V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
1.4.2.3 The electric steering column lock:
The electric steering column lock is controlled by the UCH. The steering column lock works by inserting and
removing a lock bolt. It replaces the Neimann type lock.
The steering column lock is powered outside + after ignition feed. The steering column lock supply is via the after
ignition relay (located in the Protection and Switching Unit) in its rest position, from where it is distributed to the
column lock by the UCH.
The UCH sends an unlocking request and a code to the steering column lock, via the vehicle's multiplex network.
The multiplex network unlocks the steering column lock if the code is recognised.
A sensor located on the column lock bolt informs the UCH, via the multiplex network and by wire connection, that it
is unlocked.
When unlocking is confirmed, the UCH activates the + after ignition feed via the Protection and Switching Unit. The
column lock is no longer supplied.
The column lock has a "+ after ignition feed present on vehicle" wire signal which inhibits locking while the feed is
active.
1.4.2.4 The injection computer:
The injection computer is coded and unlocks following the encrypted challenge exchange with the UCH.
1.4.2.5 The starting aerials (hands-free vehicles):
There are 3 transmitter aerials located in the passenger compartment. They are controlled by the UCH to interrogate
the card during a starting request or in confirming the presence of the card in the vehicle (e.g. after a door is
opened).
The power used allows the whole passenger compartment to be covered, including the boot. Overspill outside the
passenger compartment is minimal.
1.4.2.6 The card reader:
The card reader is connected to the UCH by a wire connection. It provides the transponder function (like a key
recognition ring). It therefore allows authentication of a Renault card without a battery.
If the card is not detected or recognised during hands-free starting, the card reader flashes to tell the customer to
insert the Renault card.IMPORTANT IMPORTANT
The steering column lock is:
–not removable when the bolt is disengaged,
–fitted with a left-hand thread self-shearing mounting bolt.

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-36
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-36V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
1.4.3.7 Automatic gearbox computer (if fitted):
The computer informs the UCH of the selector position (park, neutral, etc.) via the multiplex network.
2 AIR CONDITIONING FUNCTION
The type of air conditioning control can be displayed by configuration reading LC013 Air conditioning type and
configured using command CF019 Air conditioning type (can be configured during configuration of the UCH
by the SC008 UCH type command).
2.1 Sub-function: USER SELECTION (Non-regulated air conditioning only)
The UCH receives the signal from the air conditioning panel via cable connection for the air conditioning request, for
electric heated rear screen and the signal for passenger compartment blower operation.
The UCH sends the request to the Protection and Switching Unit to start electric heated rear screen de-icing.
The UCH sends the request to the injection system to activate the air conditioning compressor.
The following statuses can be displayed:
–ET029 Air conditioning button.
–ET028 Heated rear screen button.
–ET015 Passenger compartment fan.
Operation of the indicator lights on the air conditioning and electric heated rear screen request buttons can be
checked using the following actuator commands:
AC015 Air conditioning button indicator and AC019 Heated rear screen indicator.
2.2 Sub-function: HEATING
The UCH manages the passenger compartment heating resistors (RCHs) by controlling power relays according to
the request for ventilation in the passenger compartment, the engine coolant temperature, the external temperature,
the electrical power balance, engine loading and, for the cabriolet version, if the roof is open.
The following statuses and parameters produced by the UCH can be displayed:
–PR001 Battery voltage.
–PR002 External temperature.
–ET015 Passenger compartment blower only with non-regulated air conditioning.
–ET017 Number of RCH*s required.
–ET018 Number of RCH*s authorised by alternator alternator charge rate.
–ET019 Number of RCH*s authorised by injection system.
–ET020 Number of RCH*s activated.
–ET021 RCH* 1 control.
–ET022 RCH* 2 control.
–ET031 Fast idle request for RCH.
–ET169 Engine.
–ET025 Retractable roof for cabriolet version only.
–ET026 Heated rear screen switch.
*RCH = Passenger Compartment Heating Resistors

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-37
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-37V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
Relay 1 controls a passenger compartment heating resistor unit consisting of one resistor.
Relay 2 controls a passenger compartment heating resistor unit consisting of two resistors.
Check the operation of the passenger compartment heating resistors using actuator commands:
AC016 RCH relay 1, AC017 RCH relay 2 and AC018 RCH relay 3.
The configuration can be displayed using LC030 Heating resistor types.
2.3 Sub-function: COLD LOOP
The UCH requests the injection to switch on the compressor via the multiplex network, depending on the external
temperature, the passenger compartment blower activation signal and whether the engine is in operation. The
following statuses and parameters can be displayed:
–ET030 Air conditioning request 2.
–ET169 Engine.
–ET015 Passenger compartment fan.
–PR002 External temperature.Passenger compartment
heating resistor powerRelay 1 Relay 2
0 W 0 0
333 W 1 0
667 W 0 1
1000 W 1 1

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-38
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-38V9 MR-372-J84-87B000$129.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
3 WIPER FUNCTION
3.1 Sub-function: WIPER CONTROL
The UCH receives the driver's request when the wiper stalk is used.
Windscreen wiper:
The UCH requests the Protection and Switching Unit via the CAN network to supply power to the windscreen wiper.
The park position is managed by the Protection and Switching Unit.
The wiper control stalk has four positions (neutral, intermittent wiping, slow speed and fast speed) and a wiper
intermittent speed ring which varies the time between each wipe.
Special notes:
If the windscreen wiper is set to low speed when the vehicle is moving and then the vehicle stops, the system switches
to intermittent wipe.
The requests made to the UCH by the wiper stalk can be displayed using statuses: ET077 Wiper stalk position and
ET096 Wiper intermittent speed ring.
If the vehicle is fitted with a rain sensor, (see special features of the rain and light sensor).
Rear screen wiper:
Rear wiper speed and power supply are also controlled by the UCH.
Windscreen wiper outside neutral position:
–The rear screen wiper starts to operate as soon as reverse gear is engaged and rain drops are detected on the
windscreen wiper.
–When the vehicle is stationary, the wipers operate intermittently every 7 seconds; over 36 mph (60 km/h) they
operate every 3 seconds. There is no continuous wiping function, except during the rear screen washer control.
The statuses corresponding to operation of the rear screen wiper can be displayed using statuses ET080 Rear
screen wiper request, ET097 Rear screen wiper park position and ET109 Reverse gear engaged or ET108
Automatic gearbox lever position, by configuration reading LC064 Rear screen wiper and by configuration
CF166 Rear screen wiper.
Windscreen washers:
The front and rear windscreen washers are controlled directly by the wiper control stalk, via a wire connection.
These connections are doubled up to the UCH to permit command status reading.
ET078 Windscreen washer request,
ET079 Rear screen washer request.
Special features of headlight washers
For vehicles fitted with xenon bulbs, the headlight washers are actuated at the same time as the windscreen washer,
only if the headlights are on.
Two cases are possible concerning the control of the headlight washers.
First case: (vehicles fitted with a SIEMENS Vdiag 44 UPC): the UCH sends the command by cable to two headlight
washer relays on a relay plate underneath the UPC.
Second case: (vehicles fitted with a LEAR Vdiag 48 or later): the UCH requests the UPC via the multiplex network to
activate the washer relays.
WARNING
If the UCH does not manage to determine the position of the control stalk, or inform the Protection and Switching
Unit of the control stalk's position, the Protection and Switching Unit will activate the windscreen wiper at low speed
(defect mode).
MR-372-J84-87B000$129.mif

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-39
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-39V9 MR-372-J84-87B000$129.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
3.2 Sub-function: WIPER POWER
The UCH controls the rear screen wiper's power (and that of the headlight washers if the vehicle is fitted with xenon
headlights and a SIEMENS Vdiag 44 UPC).
Their operation can be checked using commands AC007 Rear screen wiper, AC030 Headlight washer relay 1
and AC031 Headlight washer relay 2.
Rain and light sensor
Information displays Multiplex network
Steering column
control
UCH Protection and
Switching Unit
Rear screen wiper Rear screen wiper
Windscreen and rear
screen washers
Headlight
washers