sensor RENAULT SCENIC 2008 J84 / 2.G Gas Injection LPG 3000 Workshop Manual

17C-2
MR-372-J84-17C000$059.mif
V2
17C
GAS INJECTION
Fault finding - Introduction
1. SCOPE OF THIS DOCUMENT
This document presents the fault finding procedures 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.
Type of diagnostic tools
–CLIP + multiplex line sensor
Special tooling required
3. REMINDERS
Procedure for Mégane 2
To carry out fault finding on the vehicle's computers, switch the ignition to fault finding mode (forced + after ignition).
Proceed as follows:
–Put the vehicle card in the card reader.
–Press and hold Start button (longer than 5 seconds) with start-up conditions not fulfilled.
–connect the diagnostic tool and perform the required operations.
To cut off the + after ignition feed, proceed as follows:
–disconnect the diagnostic tool,
–press the Start button twice briefly (less than 3 seconds),
–ensure that the + after ignition feed has been cut off by checking that the computer indicator lights on the
instrument panel have gone out.
Procedure for Logan
To run fault finding on the vehicle computers, switch on the ignition. Connect the diagnostic tool and perform the
required operations.Vehicle (s): LOGAN and MEGANE 2
Function concerned: Gas Injection
Engines: K4M 764/788/698Computer name: GAS 3000
Program No.: AB
Vdiag No.: 08/10
Special tooling required
Multimeter
Elé. 1681 Universal bornier
Note:
The left-hand and right-hand xenon bulb computers are powered when the dipped headlights are lit.
Fault finding on these computers is therefore not possible until after the ignition has been switched on in
diagnostic mode (forced + after ignition) and the dipped beam headlights have been switched on.
GAZ3000_V08_PRELI / GAZ3000_V10_PRELI
LPG 3000
Program No: AB
Vdiag No: 08/10
MR-372-J84-17C000$059.mif

17C-9
MR-372-J84-17C000$118.mif
V2
17C
GAS INJECTION
Fault finding - System operation
1. System operation:
Composition
–The LPG injection system consists of the:
–LPG tank,
–fuel sender,
–overpressure unit (thermally triggered),
–LPG solenoid valve relay,
–tank solenoid valve,
–reducer (LPG) or expansion valve (CNG),
–expansion valve,
–filling spigot or socket,
–LPG hose,
–tank pressure sensor,
–LPG pipes,
–unions,
–airtight cover,
–regulator valve or anti-return valve,
–excess pressure valve,
–LPG filter,
–temperature and pressure sensor,
–LPG computer,
–LPG expansion solenoid valve,
–gas injectors,
–LPG or petrol selection switch,
–fuel sender relay,
–LPG tank relay,
–fuel pump cut-off relay.
Operating principle
The GAS 3000 computer electronically manages the operation of the LPG systems (Liquefied Petroleum Gas) and
CNG (Compressed Natural Gas).
The engine must be started in Petrol mode. The vehicle will automatically switch to "Gas" mode after starting if the
"gas" configuration was selected beforehand. "Petrol" mode switches to "gas" mode after a certain time delay, which
depends on the engine coolant temperature.
Petrol mode operates autonomously. Information is shared between the Petrol computer and the LPG computer via
a CAN connection.
The K line shared by the two computers allows diagnostics to be run on both the petrol and the LPG systems.
The Petrol computer is also the supervisor of the LPG system and includes, in addition to petrol-specific functions,
functions for adapting engine management programming to LPG operation.
Therefore, the Petrol computer includes settings and variables that are specific for LPG operation, e.g. ignition
advance adjustment in LPG mode, LPG flow rate setting, richness regulation, engine operating mode, etc.
It controls the choice of program (petrol start-up etc.) and controls the transition phases for switching from one
operating mode to the other: Petrol → Gas or Gas → Petrol. The fuel pump is regularly supplied to keep the system
under pressure in the event of a possible return to "Petrol" mode (if the "Gas" tank is detected as empty or if a fault
is detected).
LPG 3000
Program No: AB
Vdiag No: 08/10
MR-372-J84-17C000$118.mif

17C-11
MR-372-J84-17C000$118.mif
V2
GAS INJECTION
Fault finding - System operation
LPG 3000
Program No: AB
Vdiag No: 08/10
17C
Expansion valve (CNG):
–Purpose:
–It enables the pressure of the gas from the tank to be lowered to a value which is compatible with the injection
system (injectors and temperature pressure sensor downstream from the expansion valve).
–The gas pressure is approximately 3 bar at the expansion valve outlet.
–It regulates the pressure in the injector rail to the pressure in the manifold.
Reducer (LPG):
– Purpose:
–It has the same functions as the expansion valve. Furthermore, it ensures that the fuel switches from a liquid state
to a gaseous state (the gas pressure is approximately 2 bar at the reducer output).
–Operation:
The LPG expansion valve and the CNG reducer are essential components and are composed of:
●a stage for lowering the pressure from 25 bar maximum to a pressure in line with the manifold pressure,
P
output = Pmanifold + 0.85 bars (LPG)
Poutput = Pmanifold + 1.8 bars (CNG with 100 bar of pressure in the tank)
●a pressure regulator, comprised of a system of valves, springs and diaphragms,
●a cut-off solenoid valve,
●a water heating system.
–The expansion solenoid valve
This component controls only supply of gas to the expansion valve. Controlled by the computer, the solenoid valve
allows LPG into the two stages of the expansion valve, thus supplying the LPG injectors.
2. Intersystem connections:
Connections to the other computers:
–Petrol injection computer,
–protection and switching unit
–instrument panel.

17C-14
MR-372-J84-17C000$236.mif
V2
17C
GAS INJECTION
Fault finding - Configurations and programming
1. CONFIGURATION
CF LC010LPG downstream temperature sensor
WITH
NONE→ CNG
→ LPG
CF LC011LPG downstream pressure sensor
NONE
SAGEMJ/JCAE
BOSCH→ LPG
→ CNG
LPG 3000
Program No: AB
Vdiag No: 08/10
MR-372-J84-17C000$236.mif

17C-15
MR-372-J84-17C000$295.mif
V2
17C
GAS INJECTION
Fault finding - Fault summary table
Tool fault Associated DTC Description
DF0032617 Engine speed inconsistency
DF0071B47 Main relay circuit
DF0131B40 Tank solenoid valve circuit
DF0141B42 Gauge supply circuit
DF0161685 Impact detected
DF0171094 LPG leak detection downstream of expansion valve
DF0180512 + after ignition feed
DF0191B05 LPG pressure sensor circuit
DF0201B45 Fuel sender switching relay circuit
DF0211B46 LPG tank solenoid valve relay circuit
DF0221B60 Computer
DF0241B43 Fuel pump cut-off relay circuit
DF026C073 Multiplex network
DF0291B20 LPG tank sender signal voltage
DF0300657 LPG tank sender supply voltage
DF0311B61 LPG pressure downstream from expansion valve
DF061C100 Multiplex network
DF0740336 TDC signal circuit
DF0800560 Battery voltage
DF0811B32 Cylinder 2 injector circuit
DF0831B00 LPG pressure sensor circuit
DF0871B34 Cylinder 4 injector circuit
DF0881B33 Cylinder 3 injector circuit
DF0921B05 Expansion valve downstream LPG pressure sensor circuit
DF0951B10 LPG temperature sensor circuit
DF0960641 Sensor supply voltage
DF0981B31 Cylinder 1 injector circuit
DF0991B49 Instrument panel indicator circuit
DF1031B41 LPG expansion valve solenoid valve circuit
LPG 3000
Program No: AB
Vdiag No: 08/10
MR-372-J84-17C000$295.mif

17C-24
MR-372-J84-17C000$354.mif
V2
GAS INJECTION
Fault finding - Interpretation of faults
LPG 3000
Program No: AB
Vdiag No: 08/10
17C
DF019
PRESENT
OR
STOREDLPG PRESSURE SENSOR CIRCUIT
CC.0: Short circuit to earth
CO.1: Open circuit or short circuit to + 12V
1.DEF: Non-compliance with emission control standards
NOTESSpecial note:
The fault is declared present when the ignition is switched on.
Manipulate the wiring harness between the LPG computer and the LPG temperature/pressure sensor in order to
produce a change in status (present to stored).
Look for any damage to the wiring harness and check the connection and condition of the LPG pressure/
temperature sensor and its connections.
If necessary, repair or replace the connector.
Check for + 5V on track 3 of the LPG pressure/temperature sensor in LPG mode.
Check the insulation in relation to earth and the continuity and the absence of interference resistance on
the connection between:
LPG computer track A3 track 3 of the LPG temperature/pressure sensor
Repair if necessary.
Check for earth on track 1 of the LPG temperature/pressure sensor in LPG mode.
Check the insulation in relation to + 12V and the continuity and absence of interference resistance on
the connection between:
LPG computer track B3 track 1 of the LPG temperature/pressure sensor
Repair if necessary.
Check the insulation, continuity and the absence of interference resistance on the connection between:
LPG computer track C3 track 4 of the LPG temperature/pressure sensor
Repair if necessary.
Replace the sensor if the LPG pressure is not greater than 2 bar in relation to the manifold pressure PR001
Manifold pressure.
Check the pressure value using parameters PR001 Manifold pressure, PR003 Pressure difference: LPG/
manifold and PR112 LPG pressure downstream of expansion valve and ensure that PR003 = PR112 -
PR001.
If the fault is still present, deal with the other faults, then proceed to the conformity check.
AFTER REPAIRDeal with any faults displayed by the diagnostic tool.
Clear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
GAZ3000_V08_DF019 / GAZ3000_V10_DF019

17C-34
MR-372-J84-17C000$354.mif
V2
GAS INJECTION
Fault finding - Interpretation of faults
LPG 3000
Program No: AB
Vdiag No: 08/10
17C
DF031
PRESENT
LPG PRESSURE DOWNSTREAM OF EXPANSION VALVE
1.DEF: Signal incoherent
2.DEF: Signal outside lower limit
3.DEF: Signal outside upper limit
4.DEF: Non-compliance with emission control standards
NOTESNone.
Manipulate the wiring harness between the LPG computer and the LPG tank pressure sensor in order to produce
a change in status (present ↔ stored).
Look for any damage to the wiring harness and check the connection and condition of the LPG pressure sensor
downstream of the expansion valve and its connections.
If necessary, repair or replace the connector.
With the engine off, switch on LPG mode and check that the sender is not at minimum.
If necessary, put some LPG back into the tank.
Check that parameter PR112 LPG pressure downstream of the expansion valve is no more than 800 mbar
greater than the manifold pressure parameter PR001 Manifold pressure.
Check the pressure value using parameters PR001 Manifold pressure, PR003 Pressure difference:
LPG/manifold and PR112 LPG pressure downstream of expansion valve and ensure that
PR003 = PR112 - PR001.
Check that the LPG supply pipes are not pinched or crushed.
Replace the faulty pipes if necessary.
If the fault is still present, deal with the other faults, then proceed to the conformity check.
AFTER REPAIRDeal with any faults displayed by the diagnostic tool.
Clear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
GAZ3000_V08_DF031P / GAZ3000_V10_DF031

17C-36
MR-372-J84-17C000$354.mif
V2
GAS INJECTION
Fault finding - Interpretation of faults
LPG 3000
Program No: AB
Vdiag No: 08/10
17C
DF074
PRESENT
OR
STOREDTDC SIGNAL CIRCUIT
1.DEF: Signal incoherent
2.DEF: Non-compliance with emission control standards
NOTESConditions for applying the fault finding procedure to stored faults:
The fault is declared present following signal incoherence.
Appearance conditions:
The fault appears when the difference between the engine speed of the petrol
computer sent by a wire connection and the engine speed sent by the multiplex
network is greater than 300 rpm.
Manipulate the wiring between the LPG computer and the petrol computer in order to produce a change in status
(present ↔ stored).
Look for any damage to the wiring harness and check the connection and condition of the TDC sensor and its
connections.
If necessary, repair or replace the connector.
Check the insulation, continuity and the absence of interference resistance on the connection between:
For Mégane 2:
LPG computer track F1
For Logan:
LPG computer track F1track C3, connector B, of the petrol computer
track 41, connector C12, of the petrol computer
Check the insulation and continuity on the wires of the following multiplex connections:
For Mégane 2:
LPG computer track A1
LPG computer track A2
For Logan:
LPG computer track A1
LPG computer track A2track K3, connector B, petrol computer
track K4, connector B, petrol computer
track 25 of the petrol computer
track 26 of the petrol computer
Repair if necessary.
If the fault is still present, deal with the other faults, then proceed to the conformity check.
AFTER REPAIRDeal with any faults displayed by the diagnostic tool.
Clear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
GAZ3000_V08_DF074 / GAZ3000_V10_DF074

17C-40
MR-372-J84-17C000$354.mif
V2
GAS INJECTION
Fault finding - Interpretation of faults
LPG 3000
Program No: AB
Vdiag No: 08/10
17C
DF083
PRESENT
OR
STOREDLPG PRESSURE SENSOR CIRCUIT
CC.0: Short circuit to earth
CO.1: Open circuit or short circuit to + 12V
1.DEF: Non-compliance with emission control standards
NOTESNone
Special note:
The fault is declared present when the ignition is switched on.
Manipulate the wiring harness between the Gas computer and the gas pressure sensor in order to produce
a change in status (present to stored).
Look for any damage to the wiring harness and check the connection and condition of the LPG pressure/
temperature sensor and its connections.
Replace or repair the connector(s) if necessary.
Check for + 5V on track 1 of the LPG pressure/temperature sensor in LPG mode.
Check the insulation in relation to earth and the continuity and the absence of interference resistance on
the connection between:
LPG computer track A3 track 1 of the LPG temperature/pressure sensor
Repair if necessary.
Check for earth on track 3 of the LPG temperature/pressure sensor in LPG mode.
Check the insulation in relation to + 12V and the continuity and absence of interference resistance on
the connection between:
LPG computer track B3 track 3 of the LPG temperature/pressure sensor
Repair if necessary.
Check the insulation, continuity and the absence of interference resistance on the connection between:
LPG computer track C4 track 2 of the LPG pressure/temperature sensor
Repair if necessary.
Replace the sensor if the LPG pressure is not greater than 2.5 bar in relation to the manifold pressure
PR001 Manifold pressure.
Check the pressure value using parameters PR001 Manifold pressure, PR003 Pressure difference:
LPG/manifold and PR112 LPG pressure downstream of expansion valve and ensure that
PR003 = PR112 - PR001.
If the fault is still present, contact the Techline.
AFTER REPAIRDeal with any faults displayed by the diagnostic tool.
Clear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
GAZ3000_V08_DF083 / GAZ3000_V10_DF083

17C-45
MR-372-J84-17C000$354.mif
V2
GAS INJECTION
Fault finding - Interpretation of faults
LPG 3000
Program No: AB
Vdiag No: 08/10
17C
DF092
PRESENT
OR
STOREDLPG PRESSURE SENSOR DOWNSTREAM OF EXPANSION VALVE
CO.0: Short circuit to earth
CC.1: Open circuit or short circuit to + 12V
1.DEF: Non-compliance with emission control standards
NOTESFault finding procedure application conditions:
Present or stored fault.
Manipulate the wiring harness between the LPG computer and the LPG pressure/temperature sensor in order to
produce a change in status (present ↔ stored).
Look for any damage to the wiring harness and check the connection and condition of the LPG pressure/
temperature sensor and its connections.
If necessary, repair or replace the connector.
Check for + 5V on track 1 (for Mégane 2) or track 3 (for Logan) of the LPG pressure/temperature sensor in LPG
mode.
Check the insulation in relation to earth and the continuity and the absence of interference resistance on
the connection between:
For Mégane 2:
LPG computer track A3
For Logan:
LPG computer track A3track 1 of the LPG temperature/pressure sensor
track 3 of the LPG temperature/pressure sensor
Repair if necessary.
Check for earth on tracks 3 and 1 of the LPG pressure/temperature sensor in LPG mode.
Check the insulation in relation to + 12V and the continuity and absence of interference resistance on
the connection between:
For Mégane 2:
LPG computer track B3
For Logan:
LPG computer track B3track 3 of the LPG temperature/pressure sensor
track 1 of the LPG temperature/pressure sensor
Repair if necessary.
Check the insulation, continuity and the absence of interference resistance on the connection between:
For Mégane 2:
LPG computer track C4
For Logan:
LPG computer track E2track 2 of the LPG pressure/temperature sensor
track 2 of the LPG pressure/temperature sensor
Repair if necessary.
AFTER REPAIRDeal with any faults displayed by the diagnostic tool.
Clear the computer memory.
Carry out a road test followed by another check with the diagnostic tool.
GAZ3000_V08_DF092 / GAZ3000_V10_DF092