Government procurement case of the EHY5045TWCE6 sewage treatment vehicle (Model 3308) in Nanjing: Fault rate analysis based on three years of actual operation. In municipal sanitation, sewage treatment vehicles are critical equipment for urban sewer networks, river remediation, and similar applications. In 2022, a district-level municipal sanitation department in Nanjing procured one EHY5045TWCE6 sewage treatment vehicle manufactured by Chengli Special Purpose Vehicle Co., Ltd. via public tender. This model is built on a Dongfeng chassis, complies with China VI emission standards, and is primarily used for emergency sewage discharge in urban low-lying areas and manholes. This article presents an in-depth analysis—based on real-world operational data from May 2022 to May 2025—covering maintenance records, fault type distribution, after-sales response time, and spare parts supply reliability, providing authentic reference data for government procurement decisions. I. Project Background and Procurement Overview In early 2022, the Urban Management Bureau of a district in Nanjing initiated a procurement project for compact sewage treatment vehicles to address recurring sewer blockages and waterlogging in low-lying areas within its jurisdiction. Following a public tender process, Chengli Special Purpose Vehicle Co., Ltd. delivered one EHY5045TWCE6 sewage treatment vehicle at a unit price of approximately RMB 280,000 (per publicly available tender information). While sharing certain chassis technologies with the CLW5070GSSD6 water-sprinkling truck, this model was specifically optimized for sewage treatment applications—including a high-capacity sewage tank, high-pressure cleaning pump, and vacuum suction system. After commissioning, the vehicle has been assigned to routine cleaning and emergency flood drainage tasks across more than 30 manholes within the district, accumulating an average annual mileage of ~5,000 km and over 1,000 operating hours per year. Per the procurement contract, Chengli provided nationwide Dongfeng chassis warranty coverage and lifetime after-sales service for the superstructure. Over the three-year period, the vehicle recorded 12 maintenance events involving the engine, hydraulic system, vacuum pump, and electronic control systems. A detailed analysis follows, based on these maintenance records. II. Fault Type Distribution and Data Analysis Based on actual maintenance records, faults were categorized into four major groups: Engine & Drivetrain; Hydraulic System; Vacuum & Discharge System; and Electronic & Control Systems. Specific data are summarized in the table below: Fault Category | Number of Incidents | Percentage | Common Symptoms | Resolution ---|---|---|---|--- Engine & Drivetrain | 3 | 25% | Unstable idle, clutch slippage | Spark plug replacement, clutch calibration Hydraulic System | 4 | 33.3% | Hydraulic oil leakage, loose pipe fittings | Seal ring replacement, fitting tightening Vacuum & Discharge System | 3 | 25% | Insufficient vacuum level, discharge valve jamming | Pipeline cleaning, valve seal replacement Electronic & Control Systems | 2 | 16.7% | Sensor failure, instrument panel alarms | Sensor replacement, reprogramming Total | 12 | 100% | — | — Data Source: Three-year maintenance records from a district-level municipal sanitation department in Nanjing (May 2022 – May 2025) As shown in the table, hydraulic system faults accounted for the highest proportion (33.3%), primarily attributable to the vehicle’s operational environment—characterized by high humidity and strong corrosivity—which accelerates aging of hydraulic piping and sealing components.