What is a Citroën C4 Coupé I airbag control unit?
The Citroën C4 Coupé I airbag control unit is the central safety unit that activates all occupant restraint systems in the event of an accident. It monitors sensors, stores crash data, and ensures the proper functioning of all airbag modules in the vehicle, which is essential for the vehicle's passive safety.
This critical electronic component is the brain of the passive safety system in your vehicle.
It continuously monitors impact, deceleration, and other accident signals to respond quickly in an emergency.
After an accident, the control unit stores relevant crash data for diagnostic purposes, which can be deleted after repair.
Why is the Citroën C4 Coupé I airbag control unit defective?
A Citroën C4 Coupé I airbag control unit becomes defective because, after an accident, it stores crash data that must be manually deleted, or internal errors such as overvoltage, moisture damage and age-related material fatigue can occur, which impair its function and cause the airbag warning light to illuminate permanently.
After a crash, the control unit stores special data that blocks it from further operation, even if there is no visible damage.
Common causes of defects include overvoltages in the vehicle electrical system, internal short circuits or water damage that damages the electronics.
The resulting internal errors often lead to communication problems or the complete failure of the airbag system.
Common error codes for Citroën C4 Coupé I airbag control unit repair
When repairing the Citroën C4 Coupé I airbag control unit, specific error codes such as B1000, B1620, 65535, and 93F9 must be taken into account. These indicate direct problems with the control unit itself, including communication errors, memory defects, or internal failures, and are crucial for a precise diagnosis.
- B1000 → Control unit communication error → Communication with the airbag control unit is not possible.
- B1620 → Airbag control unit memory error → Crash data cannot be deleted or there are internal memory problems.
- 65535 → Airbag control unit defective (internal error) → A generic internal failure or defect of the ECU has occurred.
- 93F9 → Internal error in the airbag control unit → This code occurs when there is overvoltage damage or other internal damage.
These error codes are used to accurately diagnose problems directly on the airbag control unit.
They are read out using a manufacturer-specific diagnostic device in a specialist workshop.
A correct interpretation of the codes is essential for the successful Citroën C4 Coupé I airbag control unit repair.
What part numbers are available for the Citroën C4 Coupé I airbag control unit repair?
For Citroën C4 Coupé I airbag control unit repairs, verified OEM part numbers such as 9662643680, 603725800, 9653493780, and 9807547380 are crucial. These numbers, often from Autoliv or Citroën, ensure the compatibility of the replacement or repair unit with your specific C4 Coupé I model and its proper function.
The part number 9662643680 is a frequently cited original part number from Citroën or Autoliv.
The 603725800 is another original number from Autoliv, often for petrol variants of the C4 I.
9653493780 is a specific OEM number from Autoliv that fits the C4 I Coupé airbag control unit.
The number 9807547380 is listed by Citroën as a suitable original spare part for the airbag control unit of the C4.
These numbers are directly aligned to the airbag control unit of the Citroën C4 Coupé I and have been validated several times.
Before repairing or replacing a part, it is always advisable to compare the part number with your chassis number.