2008 RENAULT SCENIC air condition

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - Introduction87B
87B-3
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - Introduction87B
87B-3V9 MR-372-J84-87B000$043.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
Faults
Faults are declared present or stored (depending on whether they appeared in a certain context and have
disappeared since, or whether they remain present but are not diagnosed within the current context).
The present or stored status of faults should be taken into consideration when the diagnostic tool is used after the
forced + after ignition feed is switched on (without acting on 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 electric lines on which there is a fault;
–The connectors on those lines (corrosion, bent pins, etc.);
–The resistance of the faulty component;
–The condition of the wires (insulation melted or split, chafing, etc.).
Conformity check
The aim of the conformity check is to check data that does not produce a fault on the diagnostic tool because the
data is inconsistent. Therefore, this stage is used to:
–carry out fault finding on faults that do not have a fault display, and which may correspond to a customer complaint.
–check that the system is operating correctly and that there is no risk of a fault recurring after repairs.
This section gives the fault finding procedures for statuses and parameters and the conditions for checking them.
If a status is not behaving normally or a parameter is outside the permitted tolerance values, consult the
corresponding fault finding page.
Customer complaints - Fault finding chart
If the test with the diagnostic tool is OK but the customer complaint is still present, the fault should be processed by
customer complaints.
A summary of the overall procedure to follow is provided on the following page in
the form of a flow chart.

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-26
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-26V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
b/ Locking the steering column:
The steering column is locked with the engine off, after the Renault card is removed from the card reader. This
locking operation requires:
–a valid 0 mph (0 km/h) speed signal,
–a correctly functioning airbag and no impact detected,
–a deactivated + after ignition connection.
When the engine has not been started but the after ignition feed is active (e.g. forced after ignition feed), certain
conditions in which there is a drop in the after ignition feed do not cause the steering column to lock ("steering
column not locked" message).
Steering column lock fails if:
1/ Normal non-locking scenarios:
–the card is present in the card reader,
–more than 20 minutes has elapsed with the card in the reader and the engine off,
–the vehicle speed is not zero,
–power is demanded by the steering column lock too frequently.
With regard to vehicles fitted with UCH computer Vdiag 4F or above:
–the Renault card is removed from the card reader when the vehicle is in forced + after ignition feed,
–3 minutes have elapsed following a starting failure due to an engaged gear,
–the Renault card is removed from the card reader following a starting failure due to an engaged gear,
–a front door is open following a starting failure due to an engaged gear and the card is not in the reader.
To lock the steering column, start and stop the engine again.
2/ Abnormal non-locking scenarios:
–the airbag unit is faulty or locked,
–the airbag unit is disconnected,
–the airbag has been triggered,
–the speed signal is not available.
In the event that a steering column does not lock, the driver is informed via the message Steering column not locked.
1.2.3 Locking the injection computer:
When the + after ignition feed has been established, the UCH and the injection computer compare their codes via
the multiplex network. If the codes are identical, the vehicle immobiliser is deactivated (ET046 Immobiliser).
If there is a failure, the immobiliser remains active.
Reactivating protection: the immobiliser is reactivated when the engine stops.

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-33
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - System operation
87B
87B-33V9 MR-372-J84-87B000$086.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
1.4.1.6 The door locking motors:
These are direct current motors (12 V supply). The door locking motors are controlled by the UCH.
The deadlocking function requires a second motor per door.
1.4.2 Main components of the PROTECTION sub-function:
The protection sub-function is based on 4 main coded components:
–The Renault cards.
–The UCH.
–The electric steering column lock.
–The injection computer.
These parts are coded definitively: a part coded for one vehicle may not be used on another vehicle.
It is possible to replace a coded part with an uncoded part using special procedures in the CLIP tool and the vehicle
repair code (See Configuration and programming).
1.4.2.1 The Renault card:
The Renault card enables the vehicle to be started in two modes:
–starting by inserting the card into the reader:
–hands-free starting without insertion of the card into the card reader (hands-free vehicles).
The Renault card is powered by a 3 V battery. This battery is necessary to operate in standard and hands-free mode.
If the battery is too old, or if the vehicle is in an area of frequency interference, hands-free starting is not possible, but
always possible by inserting the Renault card into the reader.
1.4.2.2 The UCH:
a) The UCH detects the starting request (Start button pressed under starting conditions).
b) The UCH authenticates the Renault card via the starting aerials for hands-free mode, or via the card reader for
transponder mode.
c) The UCH manages the exchange with the steering column lock:
The UCH sends an unlocking request to the steering column via the vehicle's multiplex network, and the steering
column responds with the status of the lock bolt.
d) The UCH requests activation of the + after ignition feed from the Protection and Switching Unit.
e) The UCH manages the exchange with the injection computer:
The UCH and the injection computer exchange their codes via the vehicle's multiplex network to deactivate protection
and unlock the immobiliser.
f) The UCH requests the Protection and Switching Unit to supply the starter motor.

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 - Configurations and programming
87B
87B-57
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - Configurations and programming
87B
87B-57V9 MR-372-J84-87B000$215.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
5/ TYRE PRESSURE MONITORING SYSTEM FUNCTION
5.1 PROGRAMMING PROCEDURE FOR THE 4 VALVE CODES (SC002)
SC002:
Programming the four valve codes
IMPORTANT:
Any operation involving the replacement of a wheel sensor, requires perfect knowledge of the
recommendations defined in Repair Manual 364 (for Mégane II) or 370 (for Scénic II), section 35.
●Inflate the four tyres to 3.8 bar.
●Establish communication with the UCH using the diagnostic tool.
●Select the Repair mode menu.
●Select the Programming menu.
●Select line SC002 in the Tyre function.
●The stored codes and valve sets detected are displayed.
●Select the Valve set selection menu, then Summer or Winter.
●Confirm to display the Valve programming conditions table.
●Confirm by selecting next to obtain the Find valve codes menu.
●Excite each valve by holding the valve exciter against the tyre just below the valve in question.
●Start with the front left-hand wheel.
●Wait for the new code to appear on the screen before moving on to the next valve.
●The order for programming the codes is as follows:
Front left-hand Front right-hand Rear right-hand Rear left-hand
●Click on the "Confirm" button to transmit the codes to the UCH.
●Inflate the tyres to the recommended pressures.
●Carry out a road test: speed > 12 mph (20 km/h) for 10 minutes.
●Check that no message appears on the instrument panel.
IMPORTANT:
When swapping wheels over, reprogram the UCH with the new valve positions using the diagnostic tool and
program the valve codes.
The coloured rings will then have to be placed back in the location marked on the label on the driver's door.

PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - Configurations and programming
87B
87B-62
PASSENGER COMPARTMENT CONNECTION UNIT
Fault finding - Configurations and programming
87B
87B-62V9 MR-372-J84-87B000$215.mif
UCH
Vdiag No.: 44, 48,
4C, 4D, 4F, 50
8/ UCH TYPE CONFIGURATION PROCEDURE (SC008)
8.1 Vdiag 44, 48
This procedure will enable the UCH to be configured in relation to the vehicle to provide optimum running.
–Click on the Repair mode and in the Programming menu,
–confirm line SC008 UCH type,
–follow the procedure and enter the following data:
–CF097 Vehicle type (3-door/4-door/5-door/cabriolet/extended MPV/MPV/Estate),
–confirm, follow the procedure and enter the following data:
–CF010 Hands-free function (WITH or WITHOUT),
–CF023 Tyre pressure monitoring system function (WITH or WITHOUT),
–CF057 Type of heating resistors (NONE, 1000 W, or 1800 W),
–CF019 Type of air conditioning (HEATING, AUTOMATIC, MANUAL),
–CF027 Type of windscreen (TINTED, HEAT INSULATING),
–CF035 Rain/light sensor (WITH or WITHOUT),
–CF014 Daytime running lights (WITH or WITHOUT),
–CF022 Factory fitted perimeter protection (WITH or WITHOUT): function only available on vehicles for the
Mexican market,
–CF173 One-touch window(s)/Sunroof (WITH or WITHOUT),
–confirm, follow the procedure and enter the following data:
–CF036 Selective opening of the opening elements (WITH or WITHOUT) Only if CF010 = WITHOUT
–confirm, follow the procedure and enter the following data:
–CF085 Valet card function (WITH or WITHOUT) Function only available in Mexico,
–(This status will only be available if the following conditions are met: CF036 Selective opening of opening
elements = WITH),
–check that the options configured are those desired and finish.