Fuel-Powered Preheater, Checking

Fuel-powered preheater, checking

Note! The illustrations in this service information are used for different model years and/or models. Some variation may occur. However, the essential information in the illustrations is always correct.

Test-driving

Important information
The additional heater will not start if the engine coolant temperature (ECT) is in excess of approximately 75°C.

Checking the quantity of fuel





If the engine is running
The engine coolant heater always starts. The amount of fuel in the tank is monitored for 1 minute.
If there are more than 4 liters of fuel, the engine coolant heater continues to operate.
If there are less than 4 liters of fuel, the engine coolant heater is switched off.

If the engine is switched off
The quantity of fuel must be checked before starting.

Warning text in the display
A warning text appears in the driver information module (DIM) display if:
- the quantity of fuel is too low
- the battery voltage is too low.

Conditions for starting
- the outside temperature must be below 5 °C
- the engine must be running
- the quantity of fuel must be greater than 4 liters
- no diagnostic trouble codes (DTCs) may be stored that would prevent starting
- the driver and/or passenger airbag (SRS) must not have deployed.

Activating the engine coolant heater
When the engine coolant heater is activated, allow it to run for a few minutes.
Check that:
- the engine coolant heater starts and runs normally
- the engine coolant heater does not smoke abnormally
- there is no mechanical noise from the fuel pump (FP), water pump or combustion fan
- there is no leakage from fuel lines and connections
- there is no leakage from engine coolant hoses and connections
- the coolant hoses from the engine coolant heater are warm.
Stop the engine coolant heater.
If the temperature exceeds 20 °C the engine coolant heater may run unevenly. This is due to the fuel vaporizing.
The engine coolant heater is not normally intended to operate in such high temperatures.
If the engine preheater does not have a timer, it is started in VIDA.