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 - 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-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 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 faults87G
87G-25V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF013
PRESENT
OR
STOREDVOLTAGE REGULATION
1.DEF: Voltage too low
2.DEF: Voltage too high
NOTESSpecial note:
Deal with the faults DF012 Alternator and DF007 UPC - alternator connection first
if they are present or stored.
Conditions for applying the fault finding procedure to stored faults:
The fault is declared present with the engine running.
Use Wiring Diagrams Technical Note for Mégane II or Scénic II.
Check the conformity of the wiring (see Test no. 2 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.
Check the conformity of the parameter PR004 Battery voltage (see Interpretation of parameters).
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.
USM_V48_DF013/USM_V4C_DF013
ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-26V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF014
PRESENT
OR
STOREDLEFT-HAND SIDE LIGHT CIRCUIT
CO: Open circuit
CC.0: Short circuit to earth
CO
NOTESSpecial note:
To display this fault as present or stored, run the command
AC016 Electrical supply circuit test.
Use Wiring Diagrams Technical Note for Mégane II or
Scénic II.
Check that the front left-hand side light bulb is sound.
Repair if necessary.
Check the condition and connection of the connector to the left-hand headlight, component code 227 (tabs bent,
broken, oxidised).
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 that the earth connection code MAS, for the left-hand headlight connector is perfect.
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 condition and connection of the Protection and Switching Unit 8-track connector AN (tabs broken, bent
or oxidised).
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:
–LPG between components 1337 and 227.
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 fitting and switch on the left-hand headlight.
Repair if necessary or replace the light if it is faulty.
If the fault is still present, contact the Techline.
AFTER REPAIRRun command AC016 "Electrical supply circuits test".
Erase 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_DF014/USM_V4C_DF014
ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-27V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF014
CONTINUED
CC.0
NOTESSpecial note:
To display this fault as present or stored, run the command
AC016 Electrical supply circuit test.
Use Wiring Diagrams Technical Note for Mégane II or
Scénic II.
Check the conformity of the fuse F1 (7.5A) for the Protection and Switching Unit, component code 1337.
Check the insulation, continuity and the absence of interference resistance on the following connection:
–MAS between components 1337 and 227.
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, contact the Techline.
AFTER REPAIRRun command AC016 "Electrical supply circuits test".
Erase the faults from the computer memory, switch the + after ignition supply off and
back on again and run another check using the diagnostic tool.
ENGINE COMPARTMENT CONNECTION UNIT
Fault finding - Interpretation of faults87G
87G-28V7 MR-372-J84-87G050$330.mif
UPC
Vdiag No.: 48, 4C
DF015
PRESENT
OR
STOREDRIGHT-HAND SIDE LIGHT CIRCUIT
CO: Open circuit
CC.0: Short circuit to earth
CO
NOTESSpecial note:
To display this fault as present or stored, run the command
AC016 Electrical supply circuit test.
Use Wiring Diagrams Technical Note for Mégane II or
Scénic II.
Check that the front right-hand side light bulb is sound.
Repair if necessary.
Check the condition and connection of the right-hand headlight, component code 226 (tabs broken, bent or
oxidised).
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 that the earth connection code MAS for the right-hand headlight connector, component code 226 is
perfect.
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 condition and connection of the Protection and Switching Unit 8-track AN connector, component code
1337 (tabs broken, bent or oxidised).
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:
–LPD, between components 1337 and 226.
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 fitting and switch on the right-hand headlight.
Repair if necessary or replace the light if it is faulty.
If the fault is still present, contact the Techline.
AFTER REPAIRRun command AC016 "Electrical supply circuits test".
Erase 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_DF015/USM_V4C_DF015