Functions of the injection ECU
- To control the cutting in and cutting out of the cooling fan(s) (engine cooling)
- Control of the post ventilation (for a maximum of 6 minutes)
- To control the lighting of the coolant temperature warning lamp in the control panel
- Control of the coolant temperature logometer on the instrument panel
- To carry out a diagnostic check of the operation of the cooling fan(s)
- Acquisition of the engine coolant temperature
- To manage the back-up modes
Flow chart
Key
- A - VAN network
- B - CAN network
- C - wire connection
| designation | part number in the electrical diagrams |
|---|---|
| automatic gearbox ECU (*) | 1360 |
| diagnostic warning lamp | V1300 |
| fan | 1510 |
| air conditioning compressor | 8020 |
| Fascia panel instruments (gauge and warning lamp in the instrument panel) | 0004 |
| engine coolant temperature warning light | V4020 |
| engine coolant temperature gauge | 4026 |
| built-in systems interface | BSI1 |
| centralised diagnostic socket | C001 |
| injection ECU | 1320 |
| air conditioning ECU | 8080 |
| air conditioning pressostat | 8007 |
| engine coolant temperature sensor | 1220 |
Note(*) according to specification
| no. of link | signal | nature of signal |
|---|---|---|
| 1 | engine coolant temperature sensor | frequency based |
| 2 | request to cool the automatic gearbox oil temperature (*) | CAN |
| 3 | cooling fan relay control: slow speed (1508) | all or nothing |
| cooling fan relay control: high speed (1509) | all or nothing | |
| 4 | air conditioning compressor control | all or nothing |
| 5 | request to illuminate the diagnostic LED | CAN |
| request to illuminate the coolant temperature gauge | CAN | |
| request to flash the coolant temperature warning LED | CAN | |
| engaging of the air conditioning compressor authorised (AC/OUT) | CAN | |
| 6 | request to illuminate the diagnostic LED | VAN |
| request to illuminate the coolant temperature gauge | VAN | |
| request to flash the coolant temperature warning LED | VAN | |
| 7 | request to authorise engaging of the air conditioning compressor (AC/TH) | CAN |
Note(*) depending on vehicle equipment
(1510) electric cooling fan unit
BATT+ = battery +
+APC = + ignition on
(BSM) injection double relay
(1514) fan unit relay at mid speed
There is only one type of assembly: assembly with three speed fan unit
WarningThe fan triggering levels depend on the vehicle: refer to the relevant documentation
There are 3 operating speeds
- Slow speed
- Mid speed
- High speed
Description
Slow speed is obtained by supplying the cooling fan via a resistor arranged in series in the supply circuit
The mid speed is obtained by supplying the fan through 2 resistors arranged in parallel on the supply circuit
- The slow speed relay is controlled by the injection ECU
- The mid speed relay is controlled by the built-in systems interface
Fast speed is obtained by supplying the cooling fan directly
Before switching to high speed, the fan is controlled for 3 seconds at slow speed
Before switching to mid speed, the fan is controlled for 3 seconds at slow speed (*)
(*) refer to the procedure: cooling requirement for the air conditioning (BRAC)
Electrical resistors
The 2 resistors are located on the front panel, near to the air/air exchanger and the fan
Engine coolant temperature sensor (1220)
The engine coolant temperature sensor informs the ECU about the engine coolant temperature
The water temperature sensor is fitted to the coolant unit
Request to cool the automatic gearbox oil temperature
Vehicle application: vehicle with automatic transmission
The cooling fan unit relay is activated when the oil temperature exceeds 120 °C
This command is used to cool the temperature of the following components
- Coolant
- The gearbox oil through the heat exchanger
During this operating phase, the gearbox ECU selects a gearbox heat protection law
Post ventilation
Application: vehicles all types (except monospace)
When the engine stops, the ECU will operate the post-cooling if the coolant temperature exceeds a certain threshold (105°C) (according to vehicle)
(*) depending on vehicle
Post-cooling occurs at slow speed and lasts for a maximum of 6 minutes after the engine has stopped
Back-up mode
Role of the injection ECU if the coolant temperature sensor is faulty
- To control operation of the fan at high speed
- To activate the coolant temperature warning lamp in the control panel so that it flashes (depending on the version)
- To prohibit the control of the air conditioning compressor (AC/OUT)