The electric valve of the EGR system of Citroen C4 controls the amount of recycled exhaust. When a P0402 fault code is displayed, the leakproofness of the EGR electromagnetic valve should be checked. In order to do this, two measurements of airflow parameters must be performed.
For the first measurement:
- detach the EGR electromagnetic valve,
- start the engine,
- Determine the value of the measured air flow.
For the second dimension:
- detach the EGR electromagnetic valve,
- to isolate the EGR pipe at the intake manifold,
- start the engine,
- Determine the value of the measured air flow.
In the normal operation of the EGR valve, the results of both measurements are identical. Otherwise, the EGR electromagnetic valve is not hermetically sealed.
Attention: In the absence of code, the system is not allowed to remove the EGR electromagnetic valve.