Changan Eado EV Air Conditioning System Disassembly and Diagnostic Guide

Fault Background

The air conditioning system of the Changan Eado EV (C211-EV) consists of four major subsystems: refrigeration, heating, air distribution, and climate control. Fresh air enters through the AC intake unit, passes through the dust filter → HVAC assembly duct → various vents, providing cooling, dehumidification, heating, and circulation. Features include dehumidified air, electric ventilation, front and rear windshield defogging. The driver selects cabin temperature, blower speed, and intake/outlet position from the climate control panel (automatic climate control). Torque specifications are clearly defined: compressor mounting bolts 23 N·m, high/low-pressure pipe mounting bolts uniformly 10 N·m at various points. Maintenance has three prohibitions (never mix lubricants, no welding or steam cleaning near lines, no direct refrigerant release to atmosphere, and R134a must not be mixed with R12). This article is compiled as a service guide.

System Overview and Operation

Functions: Cooling / dehumidification / heating / circulation. Air path: Fresh air starts at the AC intake unit, passes through the dust filter, HVAC assembly duct, and reaches each vent to enter the cabin.

Four major subsystems: Refrigeration system, heating system, air distribution system, climate control system.

Control panel: Automatic climate control; driver can select cabin temperature, blower speed, and intake/outlet position.

General Inspection and Safety Rules

Lubricant discipline: Must use the type and grade of lubricant specified by the compressor manufacturer; different types and grades must never be mixed (otherwise compressor damage). Lubricant absorbs moisture easily, so minimize exposure to air.

Three prohibitions: ① No welding or steam cleaning on or near vehicles with AC lines or components; ② No cleaning with water, corrosive solvents, or flammable/explosive solvents; ③ Refrigerant must not be stored in direct sunlight or near heat sources, must never be released directly into the atmosphere under any circumstances, and refrigerants must not be mixed (R134a tetrafluoroethane and R12 dichlorodifluoromethane).

Performance check: Inspect condenser core, hoses, and connecting lines for blockage or kinks; check compressor operation. Hand-feel test: Open hood and all doors → turn on AC switch → set temperature control to coldest → set blower speed to maximum → "hand-feel" the evaporator outlet pipe temperature; it should feel cold—if not, refer to the fault symptom table.

Refrigerant system pressure check: Park vehicle indoors or in shade → open windows for ventilation → turn off ignition → connect manifold gauge set (HIGH SIDE) → power up vehicle and run for 5 minutes → press AC switch and run for 2 minutes (allow extra airflow across front of vehicle during test) → compare with R-134a pressure-temperature relationship table.

Leak testing and recovery: Keep surfaces clean and dry to avoid inaccurate readings or damage to leak detector; do not inhale refrigerant vapor (irritates eyes, nose, throat); work in well-ventilated area; use recycling equipment certified to SAE J2210 for R-134a recovery; if system accidentally discharges, ventilate work area before continuing service.

Compressor and Line Disassembly/Assembly

Compressor: Disconnect battery negative cable → recover refrigerant → remove compressor high/low-pressure connecting lines → remove compressor high-pressure line mounting bolts → disconnect compressor wiring connector → remove compressor. Install in reverse order (compressor mounting bolt torque 23 N·m) → check refrigeration system for oil leaks.

Refrigerant pressure switch: Disconnect negative cable → recover refrigerant → disconnect AC pressure switch wiring connector → remove switch. Installation: Check refrigerant pressure switch seal ring condition, replace if necessary, reverse of removal.

High/low-pressure lines: Disconnect negative cable → recover refrigerant → remove AC refrigerant pressure switch → remove right front strut area high/low-pressure line mounting bolts (10 N·m) → remove motor right mount area high/low-pressure line mounting bolts (10 N·m) → remove high/low-pressure line-to-valve mounting bolts (10 N·m) to separate lines → remove front bumper → remove condenser high/low-pressure line mounting bolts (10 N·m) → remove compressor high/low-pressure line mounting bolts (10 N·m). Install in reverse order → check all AC line seal rings (replace if necessary) → charge refrigerant → perform refrigerant system leak test.

AC control module: Disconnect negative cable → remove with suitable tool; install in reverse order.

Blower speed control module: Disconnect negative cable → remove instrument panel → disconnect speed control module wiring connector → remove 2 mounting screws; install in reverse order.

HVAC assembly: Disconnect negative cable → remove instrument panel → disconnect interior electrical center wiring connector → move harness outward, disconnect instrument panel and front compartment harness connector → disconnect left front A-pillar harness connector → remove assembly; install in reverse order.

Fault Symptom Diagnosis

Fault symptom table procedure: Locate based on symptom (recirculation/fresh air door, compressor, control module, etc.); adjust recirculation/fresh air door mechanism, inspect/replace recirculation/fresh air mode motor and mechanical linkage; check compressor fuse in fuse box; check compressor connector terminal voltage; for automatic climate control, refer to AC controller terminal view and DTC table (use diagnostic scan tool to read AC controller DTCs and troubleshoot per table).

Key Parameter Quick Reference

Safety Warnings

• This article is for technical reference only. AC system service must be performed by qualified technicians per OEM specifications; refrigerant work requires ventilation and avoid inhaling vapor.
• Lubricant types/grades must never be mixed; no welding or steam cleaning near lines.
• Refrigerant must never be released directly to atmosphere; after accidental discharge, ventilate before continuing service.
• Compressor removal involves high-voltage components (if electric compressor), follow vehicle high-voltage safety procedures, disconnect negative battery cable and verify high-voltage de-energized.

Service Insights

The most important items to memorize from this AC chapter are three prohibitions and a set of torque values: mixing lubricants directly damages the compressor (different brands' additive systems are incompatible), welding or steam cleaning near lines can cause overpressure and rupture, mixing R134a and R12 destroys the system and releasing refrigerant to atmosphere is illegal—these are all "one mistake, assembly scrapped" level rules. Torque memory is simple: compressor 23 N·m, lines uniformly 10 N·m at five locations—compressor is a moving part needing full torque, lines are sealed connections that must not be over-tightened (seal ring compression depends on torque; over-tightening crushes the seal ring and causes leaks). On the diagnostic side, two field actions: "hand-feel" the evaporator outlet pipe is the fastest system-level check (if not cold, go directly to symptom table); pressure check conditions must be fully remembered—power on 5 min plus A/C 2 min; pressure readings without proper conditions have no comparative value. Finally, note electrification difference: if the Eado EV compressor is an electric compressor, before removal, besides disconnecting the negative battery cable, follow high-voltage safety procedures to confirm high-voltage de-energized—the manual's removal steps all start with "disconnect battery negative cable," which is the first step of low-voltage safety.

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【This article is for reference only】