Citroën C4 Cactus SRS Airbag and Seatbelt Pretensioner Faults - Need Help with Diagnostic Codes

[Nanipoonani]

Hi everyone,

I’ve got a Citroën C4 Cactus that was involved in a collision, and after repairing it (replaced seat, curtain, and driver’s seatbelt due to airbag deployment), I’m encountering persistent fault codes related to the SRS system. I used an Autel MaxiCheck MX900-TS to read the codes, and here’s what I’ve found:

Permanent Faults:

Code: Select all

B140A 00: Activated seatbelt pretensioners
B1410 00: Activated left side airbags
B1412 00: Activated left window airbag

Temporary Faults:

Code: Select all

B0070 1B: Driver’s seatbelt pretensioner circuit – resistance too high
B0072 1B: Passenger’s seatbelt pretensioner circuit – resistance too high
B0020 1B: Left front window airbag circuit – resistance too high
B0021 1B: Left window airbag circuit – resistance too high

I’ve cleared the fault codes multiple times, but they keep coming back. The beeping for the seatbelt doesn’t stop even though the belt is fastened.

What I’ve already done:

Checked all the wiring connections for the seatbelt pretensioners and airbags.
Reset the codes using the Autel tool.
I’m wondering if anyone else has encountered these issues after repairs and knows how to properly reset the system or resolve these errors. Is it possible that the airbag control unit still holds crash data? If so, can I reset it with the Autel MaxiCheck MX900-TS, or do I need a more specialized tool like CarProg?

Additionally, since I’ll be using the car for personal purposes and the beeping is becoming extremely annoying, if there’s a temporary solution like disabling the seatbelt warning using a resistor or any other method, I’d appreciate detailed instructions on how to do that safely.

Any advice on further steps would be really appreciated!

Thanks in advance!

[wheeler]

Once airbags have been deployed the ECU locks. simply clearing fault codes wont work. It either needs to be replaced or the crash data cleared & reset.
Not sure if the seatbelt unfastened warning comes on when the airbag ECU locks, never heard of that.
Your Autel may be able to do it but i would think you may need an external eeprom programmer like the XP400 for Autel.

[Nanipoonani]

Once airbags have been deployed the ECU locks. simply clearing fault codes wont work. It either needs to be replaced or the crash data cleared & reset.
Not sure if the seatbelt unfastened warning comes on when the airbag ECU locks, never heard of that.
Your Autel may be able to do it but i would think you may need an external eeprom programmer like the XP400 for Autel.

Thanks for the information.

I searched online and found someone with the same problem like me and he cleared/reset the SRS not the ECU.
Are you sure its the ECU that needs to be reset?

[wheeler]

Sorry, maybe it wasn't clear but I'm talking about the airbag ECU, it is the airbag ECU that locks after deployment.

[GiveMeABreak]

Perfectly clear - yes, the Airbag ECU that also controls the seat belt pre-tensioners.

A diagnostic tool may only reset some of the soft fault codes temporarily, but can't reset the actual crash data stored in the ECU. Officially the ECU has to be replaced, but there are companies that can recode the hard data of the ECU.

[Nanipoonani]

Sorry, maybe it wasn't clear but I'm talking about the airbag ECU, it is the airbag ECU that locks after deployment.

okay thank you, I found a company that will clear the airbag ECU (SRS) for 140 euro
Hope this works.
Thank you for all the help!