Denso-Common Rail System – Fuel injector solenoid valve

2 Coil
3 Solenoid armature
4 Solenoid valve

The fuel injectors are each fitted with one solenoid valve. Actuation for fuel metering is carried out by the PCM.

Current is applied to the solenoid valves in two stages. At the beginning of an injection process, the solenoid valve is actuated with a higher pick-up current so that it opens quickly.

After a short period of time, the pick-up current is reduced to a low holding current.

Effects of faults
rough engine running,
increased emissions of black smoke,
loud combustion noise
reduced power output


The monitoring system is able to identify two types of malfunctions via several electrical tests.
• Fuel metering fault of all fuel injectors,
• Fuel metering fault of a single fuel injector.

The PCM detects malfunctions based on the power consumption of the solenoid valves.

Deviations from the tolerance range result in uncontrollable fuel metering. This means that the injected quantity and the injection timing cannot be determined exactly (see Possible consequences of faults).

In addition, the fuel injectors are checked for short circuit and open circuit.

Components significant for emissions:

• Yes (MIL-active), if engine continues to run.
• No (Non MIL active), if the engine is stopped.

04. September 2018 by Ron
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