Fault phenomenon: A Wuling Hongguang 5-seater prototype produced by SAIC-GM-Wuling Automobile Co., Ltd. is equipped with a 1.5 L engine and has a mileage of more than 40,000 km. After the prototype car was dismantled, when the engineer confirmed the parts on site, he found that the branch of the engine wiring harness around the exhaust system connected to the vehicle speed sensor was scorched, and the outer bellows of the wiring harness was cracked and peeled off. The inspection confirmed that it was caused by high temperature aging.
Inspection results: The damaged wiring harness is within the normal heat-resistant radiation distance range (measured on other vehicles of the same model), and the vehicle has a loose bolt at the connection between the three-way catalytic converter and the exhaust pipe near the damaged area of the wiring harness. air leakage fault.
Reason analysis: The exclusion is the design and quality of the wire harness branch itself, and the change of the external environment – the leakage of high temperature gas is the main cause of the scorching of the wire harness.
Corrective measures: analyze the cause of high temperature gas leakage and find reliable solutions.