Flow chart
Channel E3 of the 48-way connector (CMI): input: diagnostic signal of the pre-postheating unit
Channel G3 of the 48-way connector (CMI): timing command of the pre-postheating unit
| 1320 | engine ECU |
|---|---|
| BSI1 | built-in systems interface |
| 1158 | pre-post heating control unit |
| 1160 | pre-heater plugs |
| 0004 | instrument panel |
| no. of link | signal | nature of signal |
|---|---|---|
| 1 | request for lighting of pre-heater warning lamp | CAN |
| 2 | lighting of pre-heater warning lamp | COMFORT CAN |
Pre-heater plugs (1160)
Role
The pre-post heating glow plugs allow a rapid temperature rise in the combustion chambers during the starting phase
Description
Composition of the pre-heat glow plugs
- A heating resistor
- A metallic protective cover
Pre-post heating control unit (1158)
Role
The housing supplies the pre-heating plugs with electricity following the injection ECU's commands
Description
The pre-post heating times are determined by the injection ECU
In the event of a malfunction of the pre-postheating control unit, the injection ECU memorises a fault
Electrical special features
Allocation of the channels of the 6-way connector
- Line N° 1: supply of pre-heater plug, cylinder N°1
- Line N° 2: supply of pre-heater plug, cylinder N°2
- Line N° 3: supply of pre-heater plug, cylinder N°3
- Line N° 4: supply of pre-heater plug, cylinder N°4
- Line N° 5: supply of pre-heater plug, cylinder N°5
- Line N° 6: supply of pre-heater plug, cylinder N°6
Allocation of the channels of the 5-way connector
- Line N° 1: earth
- Line N° 2: pre-post heating unit control
- Line N° 3: +APC (GO engine running)
- Line N° 4: not matched
- Line N° 5: diagnosis of the pre-postheating control unit
Location
(3) engine cylinder head
(4) electrical harness
(5) pre-heater plug
Pre-postheating
The times for pre-heating and post-heating are determined by the engine ECU as a function of the temperature of the engine coolant fluid at idling speed and at altitude
Pre-heating operation
| engine coolant temperature | pre-heating time |
|---|---|
| 60 °C | 0 seconds |
| 10 °C | 0 seconds |
| 0 °C | 4,1 seconds |
| - 5 °C | 5 seconds |
| - 10 °C | 6,5 seconds |
| - 30 °C | 20 seconds |
Postheating operation
The postheating serves to prolong the operation of the pre-heating plugs after the cold starting phase
The post-heating enables the emission of pollutants in the first few minutes after starting to be reduced
The post-heating reduces the emissions of blue smoke including at altitude
| engine coolant temperature | post heating |
|---|---|
| 60 °C | 0 seconds |
| 40 °C | 200 seconds |
| 20 °C | 190 seconds |
| - 30 °C | 155 seconds |
Parameters which could interrupt post-heating
- Coolant temperature above 40°C
- Engine speed above 3050 rpm