tire pressure RENAULT TWINGO 2009 2.G Electrical Equipment - Petrol Injection Workshop Manual

17B-6V7 MR-413-X44-17B000$010.mif
PETROL INJECTION
Fault finding – Introduction17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
4. FAULT FINDING PROCEDURE (CONTINUED)
Wiring check
Fault finding problems
Disconnecting the connectors and/or manipulating the wiring may temporarily remove the cause of a fault.
Electrical measurements of voltage, resistance and insulation are generally correct, especially if the fault is not
present when the analysis is made (stored fault).
Visual inspection
Look for damage under the bonnet and in the passenger compartment.
Carefully check the fuses, insulators and wiring harness routing.
Look for signs of oxidation.
Physical inspection
While manipulating the wiring, use the diagnostic tool to note any change in fault status from stored to present.
Make sure that the connectors are properly locked.
Apply light pressure to the connectors.
Twist the wiring harness.
If there is a change in status, try to locate the source of the fault.
Inspection of each component
Disconnect the connectors and check the appearance of the clips and tabs, as well as the crimping (no crimping
on the insulating section).
Make sure that the clips and tabs are properly locked in the sockets.
Check that no clips or tabs have been dislodged during connection.
Check the clip contact pressure using an appropriate model of tab.
Resistance check
Check the continuity of entire lines, then section by section.
Look for a short circuit to earth, to + 12 V or with another wire.
If a fault is detected, repair or replace the wiring harness.

17B-30V7 MR-413-X44-17B000$070.mif
PETROL INJECTION
Fault finding – Role of components17B
SIM 32 Injection
Program no.: D3
Vdiag No.: 44, 4C, 50
and 54
Injection computer:
The injection computer manages the entire system.
Its role is to define the engine optimum operating mode and to inform the driver (via the instrument panel, information
display, and buzzer) and to communicate with the other computers.
Fuel vapour recirculation solenoid valve:
The fuel vapour absorber works like a ''sponge'' for petrol vapours and enables gases coming from the tank to be
collected.
Upstream oxygen sensor:
This sensor measures the amount of oxygen in the exhaust gas.
The voltage supplied to the computer by the sensor indicates the amount of oxygen in the exhaust gas - a rich
mixture or a lean mixture - and a program is adopted accordingly.
Downstream oxygen sensor:
This sensor measures the amount of oxygen in the exhaust gas.
The voltage supplied to the computer by the sensor indicates the amount of oxygen in the exhaust gas - a rich
mixture or a lean mixture - and a program is adopted accordingly.
Pinking sensor:
The sensor detects engine knocking and sends its electrical signal to the injection computer.
Oil pressure sensor:
This sensor measures the engine oil pressure.
Turbocharger:
The turbocharger is used to supply the engine with more air.
Turbocharger pressure sensor:
This sensor indicates the pressure at the turbocharger air cooler outlet before the damper valve.
Ignition coil:
This acts both as an energy storage battery and a transformer. It generates high voltage ignition pulses and the
energy required to ignite the mixture.
Motorised throttle valve:
The motorised throttle valve supplies the engine with varying mixtures of fuel and air according to the load required.
This electronic control detects the position of the accelerator using a sensor (potentiometer) to inject the mixture.