Why are recall defects in automotive electrical systems concentrated in the wire harness?

In 2021, China implemented 232 batch of car recalls, involving 8.73 million vehicles. Compared with the 214 batch of car recalls in 2019 and the 190 batch of car recalls in 2020, the recall batches in 2021 are generally larger, and the number of recalls is 29% year-on-year.

On January 20, 2022, the State Administration for Market Regulation held a special press conference on "Strengthening Product Recall Supervision and Protecting the Legitimate Rights and Interests of Consumers", and the disclosed data showed that from the structural level of China's auto recall parts, more than 84% of the vehicles recalled in 2021 had electrical system and engine defects. The wiring harness is a common product defect recall in the electrical system, and there are some multinational brands that have defects in these products.

In December 2021, Ford Motor (China) Co., Ltd. filed a recall plan with the State Administration for Market Regulations in accordance with the requirements of the Regulations on the Administration of the Recall of Defective Automobile Products and the Measures for the Implementation of the Regulations on the Administration of the Recall of Defective Automobile Products. Decided to recall 2,134 imported Lincoln Aviator vehicles of the 2020 model year produced from June 28, 2019 to October 16, 2019, effective December 10, 2021. In some vehicles within the scope of this recall, the battery wiring harness may not be properly fixed. After long-term use of the vehicle, the air conditioning compressor pulley may wear the battery wiring harness insulation, resulting in short circuits and potential fire risks of the harness, and there is a safety hazard.

In November 2021, Mercedes-Benz announced a recall for the European market for the EQC produced between December 11, 2019 and May 18, 2020, and a recall of 3,073 EQCs in the German market. The reason for this recall is that on some EQC vehicles, the harness of the vehicle steering system may have been damaged during assembly. During the owner's subsequent use of the vehicle, water may enter the wiring harness through the damaged barrier, and over time, water will enter the steering control unit, which may cause the steering assistance system to fail. When the system fails, a red warning message appears on the car's dashboard.

On the one hand, the reason for the recall of car companies is to continuously improve the technology to solve past problems; on the other hand, the reason is that the car companies have a stronger sense of responsibility, which is one of the main reasons for the increase in the number of recalled vehicles in 2021 by nearly 30% year-on-year.

Defects in the vehicle's electrical system in the car recall are a relatively high proportion of the problem. Today's cars, including new energy vehicles, rely more on electrical systems and OTA upgrades, and with the use of a series of new technologies, new systems, and new software on the car, although some problems are difficult to avoid, continuous optimization is the responsibility that car companies must bear. The risks posed by the vehicle's electrical and electronic systems are sometimes not necessarily addressed, but recalls can provide consumers with a safer and more reliable experience. At the same time, this also reflects that safety is the first "red line" of automotive technology.

The design process problem can not be ignored.

One of the reasons for the 2021 automotive wiring harness recall is design and process issues. There were 16 recalls due to wiring harnesses in 2021.

Among them: there are 9 cases of wiring harness interference, 1 case of terminal tin whiskers not being treated cleanly, 1 case of poor connector contact, 1 case of unstable welding of solder joints, 2 cases of wire harness fixed bolt torque that does not meet the requirements, 1 case of damage to the assembly of wire harness, and 1 case of terminal selection deviation.

In May 2021, Mercedes-Benz (China) recalled 31 imported E-class, AMG GT vehicles due to wear and tear caused by the failure to install the starter power supply harness in accordance with the specifications, and some vehicles within the scope of this recall may not be installed in accordance with the specification due to production deviations. The starter power supply harness may come into contact with the starter shell, the wiring harness insulation layer may be short-circuited due to long-term wear, and the risk that the vehicle cannot be started or caught on fire due to the short circuit of the wiring harness cannot be ruled out, and there is a safety hazard.

Manufacturing process defects, the main reason is still caused by two major factors of management and cost. On the one hand, automobile manufacturing from parts to the whole vehicle, involving many process links, any link of negligence, will leave a large or small safety hazards, such as the above model recall reasons "starter power supply harness is not installed in accordance with the specifications and cause wear" problem, is obviously the parts manufacturing process quality control is not strict, the degree of management refinement is not high caused by defects. Some parts companies may neglect quality management in the case of full orders, as the saying goes, "turnips are fast and do not wash mud".

In the past two years, the Japanese media has exposed the problem of counterfeiting by Japanese parts and components companies more than once, and the root cause is the defect in the management of product quality. On the other hand, many brand parts and vehicles nowadays use some low-cost, insufficient performance parts to replace the previously high-cost qualified parts for the sake of reducing costs, which is also a product defect caused by the "defect" of corporate social responsibility, which is worth learning from all enterprises.

Design defects, which account for the majority of the recalled vehicles, can take a variety of forms.

In the car recalls caused by wiring harnesses, whether it is the number of recalls or the number of recalls, harness design is the most important cause of failure, accounting for more than two-thirds of the total.

In the three components of harness design: principle design, 3D wiring design, and 2D design, 3D wiring has undoubtedly become the hardest hit area leading to the recall.

In March 2021, Toyota China recalled 2,109 Weisa vehicles due to interference between the door wiring harness and the waterproof cover, resulting in the possible disconnection of the rear airbag sensor harness. Toyota Motor (China) Investment Co., Ltd. filed a recall plan with the State Administration for Market Regulations in accordance with the requirements of the Regulations on the Administration of the Recall of Defective Automobile Products and the Implementation Measures for the Regulations on the Administration of the Recall of Defective Automobile Products.

Decided to recall a total of 2,109 imported Toyota Wesa vehicles manufactured between April 10, 2012 and July 1, 2015, effective July 15, 2021. Some vehicles within the scope of this recall are bent due to interference between the door wiring harness at the door hinge of the driver's seat and the waterproof cover, resulting in the long-term use of the rear airbag sensor harness may be disconnected due to metal fatigue, causing the airbag warning light to light up. When a vehicle collides, the side airbags and curtain airbags may not be deployed normally, increasing the risk of injury to the occupants in the collision accident and causing safety hazards. That's the problem with design.

However, traditional design issues are not necessarily problems with harness design.

The particularity of the wiring harness is flexible and easy to adjust. Make it easier to adjust the harness when it encounters design problems, and redesign to avoid some problems. As mentioned above: "Due to the interference between the door wiring harness and the waterproof cover", the designer can not change or redesign the waterproof cover. Obviously, the wiring harness is easier to adjust, and the cost of changing it is lower relative to changing the waterproof cover.

From design to manufacturing and service, all aspects of automotive cannot be ignored. Car users may be more susceptible to some related problems, whether it is a design flaw or a "user manual description is incorrect", they are certainly not the problem of improper use by the user. Enterprises treat users attentively, will consciously eliminate the "blockages" in management, manufacturing, service and other aspects, provide users with excellent quality, good consistency, safe and reliable automotive products, and will not have problems such as "wrong description" in user manuals.

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According to data from the State Administration for Market Regulation, by the end of 2021, China will have implemented a total of 2,423 automotive product recalls, involving 91.3 million defective products. In the past 5 years, auto safety recalls have occurred on average once every 1.6 days, and it has become the norm for auto companies to proactively identify problems and proactively recall.

By the end of 2021, China will promote 229 new energy vehicle recalls by automakers, involving a total of 1.98 million vehicles. Among them, the reasons for the recall are concentrated in quality problems such as vehicles, internet of vehicles, and electronic motors. "The rapid development of new energy vehicles in recent years, it is not surprising that these problems have arisen, the key is to improve the relevant measures and systems from many aspects, and strengthen quality supervision." Shuai Shijin believes that on the one hand, enterprises should assume the main responsibility for product manufacturing, improve the quality management system, strictly control quality, improve product quality and consistency, and reduce defects as much as possible; find problems, immediately take the initiative to recall and solve problems; on the other hand, the relevant national competent departments should strengthen product quality supervision, improve relevant national standards and systems, so that automobile enterprises and automobile products have rules to follow and have rules to follow.