2008 RENAULT SCENIC sensor

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Introduction87G
87G - 2V7 MR-372-J84-87G050$055.mif
187G
UPC
Vdiag No.: 48, 4C ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Introduction
1. SCOPE OF THIS DOCUMENT
This document presents the fault finding procedure applicable to all computers with the following specifications:
2. PREREQUISITES FOR FAULT FINDING
Documentation type:
Fault finding procedures (this manual):
–Assisted fault finding (integrated into the diagnostic tool), Dialogys.
Wiring Diagrams:
–Visu-Schéma (CD-ROM), paper.
Type of diagnostic tools:
–CLIP + multiplex line sensor
Special tooling required:Vehicle(s): Mégane II, Scenic II
Function concerned: Engine compartment
connection unitName of computer: Protection and Switching Unit
Program No.: C54
Vdiag no.: 48, 4C
Special tooling required
Multimeter, oscilloscope
Elé. 1681Universal bornier
USM_V48_PRELI/USM_V4C_PRELI
MR-372-J84-87G050$055.mif

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-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 - Interpretation of faults87G
87G-22V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 4C
DF009
PRESENT
OR
STORED+ APC CIRCUIT
1.DEF: Permanent low level
2.DEF: Permanent high signal
NOTESSpecial note:
This fault only applies to Vdiag 4C.
Conditions for applying the fault finding procedure to present faults:
The fault is declared present after the ignition has been switched on.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Check the connection and condition of the LPG electric control unit connector, component code 997.
Check for a voltage on connection AP31 to the connector for the LPG electric control unit, component code 997.
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.
Check the connection and condition of the multifunction switch, the reverse gear switch and the manual
gearbox neutral sensor/reversing lights, component codes 485, 155, and 1109.
Check for a voltage on connection AP11 to the connectors for the multifunction switch, the reverse gear switch
and the manual gearbox neutral sensor/reverse lights, component codes 485, 155, and 1109.
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.
Check the connection and condition of the passenger compartment electric control unit, component code 645.
Check for a voltage on connection APCB to the connector for the passenger compartment electric control unit,
component code 645.
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.
Check the connection and condition of the electric steering column lock, component code 1088.
Check for a voltage on connection AP15 to the connector for the electric steering column lock, component code
1088.
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.
Check the connection and condition of the airbag/pretensioner electric control unit and the electric power-
assisted steering system, component codes 756 and 1232.
Check for a voltage on connection AP44 to the connectors for the airbag/pretensioner electric control unit and
the electric power-assisted steering system connectors, component codes 756 and 1232.
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.
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_V4C_DF009

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of statuses87G
87G-65V7 MR-372-J84-87G050$550.mif
UPC
Vdiag No.: 48, 4CENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of statuses
ET002
FRONT WIPER PROTECTION
NOTESSpecial notes:
Only apply the checks if the status is ACTIVE or BLOCKED.
If the status is ACTIVE, this indicates that after a wiping request, the Protection and
Switching Unit has detected abnormal operation for more than 6 seconds
(constrained or blocked).
If the status is BLOCKED, this means that the total duration of intermittent pauses is
greater than 2 minutes.
The status returns to INACTIVE as soon as the UCH requests another wiping setpoint
(wiper control adjusted, or request by the rain sensor).
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Make sure that nothing is mechanically blocking the movement of the wiper arms (blades stuck, condition and
assembly of the wiper mechanism linkage and that there are no objects that could impede the movement of the
mechanism).
Check that the wiper mechanism is not seized.
Repair if necessary.
Check the condition and connection of connectors CT1 and CN on the Protection and Switching Unit,
component code 1337.
If the connectors are faulty and 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 condition and connection of the windscreen wiper motor connector, component code 212.
If the connector is faulty and 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 connections:
–14M between components 1337 and 212,
–14L between components 1337 and 212,
–14K between components 1337 and 212.
If the connections are faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
If the fault is still present, contact the Techline.
AFTER REPAIRRepeat the conformity check from the start.
USM_V48_ET002 /USM_V4C_ET002
MR-372-J84-87G050$550.mif

ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of statuses87G
87G-66V7 MR-372-J84-87G050$550.mif
UPC
Vdiag No.: 48, 4C
ET004
REVERSE GEAR ENGAGED
NOTESSpecial notes:
Only apply the checks with the ignition switched on and when no faults are present.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
5- and 6-speed manual gearbox
Check the condition and connection of the connector of the reverse gear switch, component code 155, the
manual gearbox neutral/reversing lights sensor, component code 1109, and UPC connector MN,
component code 1337.
If the connector is faulty and 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 ignition on and reverse gear engaged, check for + 12 V on connection codes H66P and AP11 of
Protection and Switching Unit connector MN, component code 1337.
If the connection is faulty and 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:
–AP11 between components 1337 and 1109,
–H66P between components 1337 and 1109.
Reverse gear engaged:
–between AP11 and H66P on component 155.
If the connections are faulty and there is a repair procedure (see Technical Note 6015A, Electrical wiring repair,
Wiring: Precautions for repair), repair the wiring, otherwise replace it.
If the fault is still present, contact the Techline.
AFTER REPAIRRepeat the conformity check from the start.
USM_V48_ET004 /USM_V4C_ET004