Mercedes Airbag System Fault
When it comes to customer safety at Fergies, it is our number one priority. With a host of Mercedes experts on hand to assist, we work together to effectively diagnose and fix our customer’s vehicles with the utmost care and attention.
Being the local experts for the Thatcham and Newbury area, we have decades of experience handling all Mercedes models. Using only genuine parts during our repairs to ensure complete peace of mind for our customers.
This, combined with our thorough 15-step diagnostics process means that our Mercedes experts can understand what’s wrong quickly and efficiently. We only replace parts that need replacing and this gives our customers complete peace of mind when their vehicle enters our workshop whilst also saving them money.
Faulty Mercedes C220 AMG Sport
A recent client came to us with an airbag and bonnet fault in their Mercedes C220 AMG. A bonnet open warning light was on as was the airbag warning light. Our technicians soon noticed the warning lights, but also spotted that the bonnet was not open. Our previous knowledge pointed us to a communication issue within the vehicle’s software. But we needed to dig deeper to confirm this.
At our Mercedes workshop, we used our dealership-level diagnostics machine to tap into live vehicle data and fault codes. The scan of the C220’s computer system displayed the following fault codes:
- A207/B2207 Internal fault in the control unit
- A761/C240300 Right front reversible emergency tensioning retractor
- 520201/C120201 A1 instrument cluster is faulty
- 520400/C120400 No message was received from the control unit central gateway
As we knew the bonnet was shut and the switches confirmed as closed, our experts moved on to focus on the airbag access control module.
This control module helps deploy the airbags. Using information from the impact sensor, the control module will control airbag deployment. Without a functioning control module or sensor, the occupant’s risk is higher as the airbags might not deploy when they are supposed to.
Our team were on hand immediately to strip back the airbag control module to see if the groundings and power connections were functioning. Thankfully they were, so our attention moved to the module itself.
Everything leading up to the module was functioning as it should have, which suggested that the airbag control module itself needed replacing.
Replacing The Airbag Control Module
We are your local Mercedes repair specialists and know the best practices when it comes to fixing our customer’s vehicles. In every case, we use genuine Mercedes replacement parts, or high-quality alternatives, to make sure nothing is left to chance.
Upon replacing the airbag control module, we discovered an interesting insight when trying to re-code the new module with the vehicle. Our technicians noticed that the re-coding was not possible as there was another fault in the system. Other workshops might not have addressed or even spotted this fault, but Fergies dedicated team are Mercedes experts and knew what to do next.
This fault did not appear before, meaning the old module was not communicating properly. This new fault meant we could tap into our extensive knowledge to fix the problem once and for all. This new fault pointed to a problem with the pyro fuse, which is a special fuse that prevents short-circuiting and reduces the risk of fires when the car is involved in a crash.
Looking at Mercedes’s wiring information, we located the pyro fuse and noticed it was broken. The reason why it was broken was to do with a previous vehicle battery replacement as the connector is next to the battery, and it got damaged.
The faulty pyro fuse will send a signal to the access control module which falsely detects that the car was in a crash. The whole system was tricked into thinking it had deployed the airbags as a result.
We sourced a pyro fuse connector repair kit and wired the new connector into the Mercedes which meant the system was now working. Once we re-coded the module, we tested the system to make sure it worked.
Fergies is Your Local Mercedes Specialist
Thanks to our expertise and commitment to providing quality servicing and repairs, our team at Fergies are Mercedes specialists. We quickly identified the issue, located the necessary parts, and restored the vehicle to working condition in just three business days. This efficient process not only saved the client time but also ensured they didn’t have to spend extra money on unnecessary repairs.
Our client was pleased to have their Mercedes C220 AMG back in perfect condition, with all the required work completed and verified, all at local garage rates.
To schedule your Mercedes service with Fergies, simply get in touch with our team today at 01635 778002.
