Engine will not start


In this repair case, the customer complained that the engine would not start on their Citroën C1 1.0 l (year of construction from 2017, engine code CFA) even with external start assistance.



It was not possible to read out the fault memory due to undervoltage. Communication could not be established between the vehicle and the diagnostic unit because the capacity of the vehicle battery was only about 20%. Even after installing a new battery, the engine would not respond at first. Except for a quiet click when operating the ignition key, nothing could be heard. The entire vehicle is de-energised, which also explains why reading out the faults failed.


The solution

Since no voltage could be detected on the vehicle and no current flow could be detected going from the new, fully-charged battery to the vehicle, the fault had to be sought in the direct vicinity of the battery. When using a multimeter and voltage tester for fault diagnosis, a fuse that had been burnt through was found to be responsible. The fuse is located in the engine compartment below the fuse box behind a cover flap. If this fuse is defective, all current flow from the battery to the vehicle is prevented.


Repair tip

Replace the defective fuse (125A) with a new one. Citroën/Peugeot article number: 6500FJ Note: The problems described above may also occur in the following vehicles that are identically constructed:

  • Toyota Aygo
  • Peugeot 107


Repair/maintenance work must always be carried out by a specialist who has completed training in the motor vehicle trade (e.g. motor vehicle mechanic, motor vehicle electrician, motor vehicle mechatronics technician).