Engine management system (Renault Espace III)

Electrical power supply for the G8T 714 engine

From the ignition switch, voltage is supplied to the A1 contact of the engine control unit. This circuit is protected by a 30 A fuse (F38). located in the passenger compartment of the vehicle. The relay power supply circuit supplies voltage to the engine control unit (contact AZ connector) and is protected by a 15 A fuse (F24) located in the vehicle interior.

After the ignition is turned on, power is supplied to the control unit via contacts 16 and 33 of the connector, as well as via contact 2 of the fast idle speed solenoid valve connector, contact 1 of the injection timing control solenoid valve connector, contact 1 of the ECR solenoid valve connector and contact 2 of the engine preheating unit relay. A constant positive voltage is supplied to the engine preheating system unit via a 70 A fuse (fuse F49).

contact No	Assigning contacts
1	Power supply (+5V) of the load potentiometer
2	Load potentiometer signal
3	Air temperature sensor signal
4	Coolant Temperature Sensor Signal
5	EGR Solenoid Valve Vacuum Sensor Signal
6	Diagnostics of short circuit of glow plug power supply circuits
7	Injector Needle Lift Sensor Signal
8	Crankshaft Position and Mode Sensor Signal
9	Diagnostic line
10	Not used
11	Not used
12	Control of preheating operation
13	Not used
14	Power supply for the injection timing advance control solenoid valve
15	Power supply for the EGR solenoid valve
16	+ 12 V ARS
17	"Weight"
18	"Weight"
19	load potentiometer "mass"
20	Power supply (+5V) of the EGR electromagnetic valve vacuum sensor
21	"Ground" of the air and coolant temperature sensor
22	"Ground" of the EGR electromagnetic valve vacuum sensor
23	Shielding shell of the crankshaft speed and position sensor and the injector needle lift sensor
24	"Mass" of the injector needle lift sensor
25	Crankshaft speed and position sensor signal
26	Diagnostic line
27	Power supply for the malfunction indicator lamp
28	Fast Idle Speed Solenoid Valve Power Supply
29	Air conditioning compressor on signal
30	Not used
31	Information about engine operating mode
32	Glow plug power supply
33	+ 12 V ARS
34	"Weight"
35	"Weight"

Electrical power supply for the G8T 716 engine

From the ignition switch, voltage is supplied to contact A1 of the engine control unit, which supplies power to the speed sensor. This circuit is protected by a 30 A fuse (F38), located in the passenger compartment.

The relay power circuit supplies voltage to the engine control unit (contact AZ connector) and is protected by a 15 A fuse (F24) located in the vehicle interior.

After the ignition is turned on, power is supplied to the control unit via contacts A4 of connector 2, as well as via contact 2 of the ECR electromagnetic valve connector. A constant positive voltage is supplied to the engine preheating system unit via a 70 A fuse (fuse F49).

contact No	Assigning contacts
Connector #1
A1	Load potentiometer signal
A2	Air temperature sensor signal
AZ	Crankshaft Position and Mode Sensor Signal
A4	Crankshaft Position and Mode Sensor Signal
B1	Not used
B2	Coolant Temperature Sensor Signal
B3	"Ground" of the air and coolant temperature sensor
B4	load potentiometer "mass"
C1	Not used
C2	Not used
SZ	Power supply (5V) of the load potentiometer
C4	Not used
Connector #2
A1	Diagnostic line
A2	+ starter
AZ	"Weight"
A4	+ 12VARS
B1	Air conditioning system information
B2	Control of the KSB solenoid valve (12 V)
VZ	Not used
B4	Not used
C1	Engine warm-up indicator ground control
C2	Diagnostic line
SZ	EGR valve ground control
C4	Control of the solenoid valve ALFB
Connector #3
1	Power supply for glow plugs 1-3
2	Power supply for glow plugs 2-4

Diagnostic tests

• The diagnostic tests listed below apply to the vehicles covered in this Workshop Manual.
• The electrical characteristics of the components of the fuel system can be measured using a digital multimeter.
• To carry out the inspection, you must have basic skills in working with electronic equipment.
• Before starting the diagnostic check, it is necessary to perform a preliminary check.
• The check can be carried out only if you know the operating principle of the fuel system.
• Diagnostic testing should begin with an analysis of the symptoms of the malfunction.

Preliminary checks

• Check the condition of the engine starting circuit: battery, power wires and starter.
• Check the condition of the engine preheating system.
• Check the condition of the fuses.
• Make sure there is enough fuel in the car tank.
• Check the air supply system for integrity and absence of damage to the air pipes, tightness of the connection points, cleanliness of the air filter and its correct fit, as well as the reliability of tightening the clamps.
• Check the condition of the exhaust system: tightness of the elements and their connections.
• Make sure the engine mechanicals are in good condition, the valve timing is correct and the cylinder head gasket is tight

General power supply check

This test consists of ensuring that the fuel system is electrically powered and must be carried out with the connector connected to the engine control unit.

Engine G8T 714

Engine G8T 716

Checking sensors, solenoids and wires

This check consists of checking the condition of the fuel system peripherals, which must be carried out with the connector connected to the engine control unit. When checking, all peripheral connectors must be connected to them.

Engine G8T 714

Engine G8T 716

Checking the power supply of sensors and electromagnetic valves of the fuel system

This control consists of checking the supply voltage or the signal of the sensors, which must be carried out with the connector connected to the engine control unit

Engine G8T 714

Engine G8T 716