Delete Crash Data After Accident: Here's How
Delete Crash Data After an Accident: Here's How It Works
After an accident, the airbag control unit stores crash data in EEPROM memory and locks itself. This data cannot be deleted with standard diagnostic tools – a specialized service center is required to access the EEPROM chip directly. Repair costs up to 50% less than a new control unit.
When airbags or seatbelt pretensioners are deployed in an accident, the control unit automatically stores crash data and sets a deployment flag. After that, the device is locked – it cannot perform any further deployments and the airbag warning light stays on permanently. Many workshops recommend expensive replacement, even though the control unit is repairable in most cases.
What is crash data in the control unit?
Crash data is information that the airbag control unit stores in non-volatile EEPROM memory at the moment of airbag deployment. It contains deployment time, activated ignition circuits, sensor values, and a lock flag that deactivates the control unit for further use.
| Stored Information | Purpose | Deletable? |
|---|---|---|
| Deployment Flag (Crash Flag) | Locks the control unit after deployment | Only via EEPROM programming |
| Ignition Circuit Log | Documents which airbags/seatbelt pretensioners were deployed | Only via EEPROM programming |
| Sensor Values at Crash Time | Accident reconstruction for experts/insurance | Only via EEPROM programming |
| Fault Codes (DTCs) | Show locked ignition circuits | Not deletable with standard diagnostics |
| Event Counter | Counts the number of deployments | Only via EEPROM programming |
Why does the control unit lock itself?
The lock is a safety feature implemented by vehicle manufacturers. After an airbag deployment, it cannot be guaranteed that all components are still intact. The control unit therefore prevents further deployments until a service center has inspected and reset the system. Manufacturers generally prohibit the reuse of deployed airbag components – however, the control unit itself is exempt from this, provided it is mechanically and electronically intact.
Why can't the workshop delete the crash data?
Standard workshop diagnostic tools – even expensive brand diagnostic systems – do not have write access to the protected EEPROM memory area of the airbag control unit. Vehicle manufacturers deliberately block this function to prevent uncontrolled reuse. Only specialized service centers can access the chip directly using EEPROM programming devices.
| Method | Crash Data Deletable? | Explanation |
|---|---|---|
| Disconnect Battery | No | EEPROM retains data without power |
| Standard OBD-2 Adapter | No | No access to SRS EEPROM |
| VCDS / OBDEleven | No | Can only delete simple DTCs, not crash flags |
| Brand Diagnostics (Star, ODIS, ISTA) | No | Manufacturer blocks EEPROM write access |
| EEPROM Programming (Service Center) | Yes | Direct access to the memory chip |
How Professional Crash Data Deletion Works
When deleting crash data professionally, the service center uses specialized programming hardware to access the EEPROM chip of the control unit directly. The crash flags are reset, the firmware is checked, and checksums are recalculated. After programming, the control unit is fully functional again.
- Remove Control Unit: The airbag control unit is removed from the vehicle
- Open Housing: Gain access to the circuit board
- Identify EEPROM: Locate the memory chip on the board
- Read Data: Back up and analyze current EEPROM contents
- Delete Crash Data: Reset deployment flags and crash logs
- Calculate Checksum: Create new checksum for correct memory contents
- Write EEPROM: Write cleaned data back to the chip
- Function Test: Test control unit for correct operation
- Installation: Reinstall control unit in vehicle – plug and play
Does the control unit need to be sent in?
Yes, typically the control unit must be sent to the service center, as EEPROM programming requires specialized hardware. At Airbag24, repair takes 3–4 business days including shipping. Express repairs are available upon request.
When is crash data deletion worthwhile?
Deleting crash data makes sense when the control unit is mechanically and electronically intact – meaning it is only locked by the stored data. In approximately 95% of cases, the control unit is fully functional again after the crash reset. Replacement is only necessary if there is physical damage to the device (cracks, burned components).
| Situation | Crash Data Deletion Possible? | Recommendation |
|---|---|---|
| Airbag Deployed, Control Unit Intact | Yes | Crash Reset at Service Center |
| Seatbelt Pretensioner Deployed, Control Unit Intact | Yes | Crash Reset at Service Center |
| Control Unit Mechanically Damaged | Inspection Required | Service Center Checks Repairability |
| Control Unit Destroyed by Water | Possibly with Component Replacement | Repair + Crash Reset Combined |
| Electronics Components Burned | Only with Additional Repair | Service Center Assesses Effort |
Crash Data Deletion: Costs and Alternatives
Professional crash data deletion costs a fraction of a new control unit. While purchasing a new unit from an authorized dealer often costs 500–1,500 euros, repair is significantly less. Find exact prices for your vehicle model in our shop – Airbag24 repairs control units from all manufacturers.
| Option | Advantages | Disadvantages |
|---|---|---|
| Crash Reset at Service Center | Affordable, your own unit, no coding required | Shipment required (3–4 business days) |
| New Control Unit (Authorized Dealer) | Original replacement part | Very expensive, coding/programming required |
| Used Control Unit | Cheaper than new part | Must be coded, unknown history |
Advantage of Repair: No Coding Required
A key advantage of crash reset over replacement: your own control unit is already coded to your vehicle. After deleting the crash data, it can be reinstalled directly – without time-consuming reprogramming or adaptation. With a replacement unit, the workshop would first need to program the new control unit to the vehicle, which incurs additional costs.
What else needs to be done after the crash reset?
After deleting crash data, the entire SRS system must be inspected and restored. Deployed airbags and seatbelt pretensioners must be replaced with new units. Only when all components are intact and the fault memory is clear will the airbag warning light go out.
- Replace Airbags: Replace all deployed airbags with new units
- Replace Seatbelt Pretensioners: Renew deployed seatbelt pretensioners
- Check Crash Sensors: Replace damaged sensors
- Check Wiring: Inspect all SRS cables and connectors for damage
- Install Control Unit: Mount repaired control unit
- Clear Fault Memory: Delete remaining DTCs with diagnostic tool
- System Test: Turn on ignition – warning light must go out after self-test
Frequently Asked Questions About Crash Data Deletion
Here you'll find answers to the most important questions about deleting crash data in the airbag control unit.
Is deleting crash data legal?
Yes, deleting crash data as part of proper vehicle repair is legal. The requirement is that all damaged safety components (airbags, seatbelt pretensioners, sensors) are properly replaced. It would be prohibited to delete the data to conceal accident damage when selling a vehicle.
Can every workshop delete crash data?
No. Most workshops – including authorized dealers – do not have the necessary EEPROM programming hardware. They typically recommend purchasing a new control unit. Specialized service centers like Airbag24 have the expertise and equipment for this work.
Does the control unit work perfectly after the reset?
Yes, in approximately 95% of cases, the control unit is fully functional again after professional crash reset. It works like a new unit and can reliably perform all safety functions. If inspection reveals that the unit cannot be repaired, the customer will be informed.
How long does the repair take?
At Airbag24, standard processing time is 3–4 business days including shipping. Express repairs are available upon request. The control unit is shipped back immediately after repair and can be installed right away – no further programming or coding required.