AITO M5 High-Voltage System Disassembly and Torque Quick Reference Guide

Fault Background

The high-voltage system disassembly of the AITO M5 (2022 model) covers four subsystems: battery pack, charging system, high-voltage wiring harness, and electric drive. The manual provides a unified high-voltage operation discipline and torque quick-reference system: battery pack-to-body mounting bolts 120±6N·m (maximum grade), front drive motor mount 70±4N·m, on-board charger bracket and generator controller 25±2N·m, high-voltage harness and ground points 10±1N·m / 10±0.5N·m (mainstream grade), battery PTC and three-phase harness 6±1N·m (small grade). When replacing the battery pack, it is mandatory to rewrite the VIN + match SK + clear DTCs. For connector installation, use a pull-back force not exceeding 20N to verify. This article organizes the disassembly and torque quick-reference guide by subsystem.

High-Voltage Operation Discipline

Three warnings: ① During operation and maintenance, do not wear metal jewelry, watches, or other metal accessories; ② During repair and maintenance, use insulated, professional tools, and wear insulated gloves and insulated shoes; ③ It is strictly forbidden to operate bare-handed without protective equipment.

Authorization threshold: Repair and maintenance of the battery system and high-voltage system of new energy vehicles must be performed by professional technicians with battery expertise, an electrician's certificate, and Jinkang technical training and authorization, to avoid personal injury, battery burnout, fire, and other accidents.

Protection and tools: Carbon dioxide or dry powder fire extinguisher, goggles, electrician's insulated shoes, electrician's insulated gloves, insulated wrenches, insulated ratchet wrench socket tool set, insulated screwdrivers (cross-head magnetic, for screw removal and installation).

General pre-sequence: Disconnect the negative battery cable → Lift and support the vehicle → (If coolant involved) Drain coolant → (If battery/motor involved) Remove the manual service disconnect switch.

Battery Pack Assembly

Removal: Disconnect negative terminal → Lift and support → Drain coolant → Remove manual service disconnect switch → Remove chassis pipe guards → Remove front muffler assembly with accessories → Remove front muffler heat shield retaining nuts and bolts (8±1N·m) → Disconnect battery pack front high-voltage harness assembly from battery pack → Disconnect front compartment harness assembly (left rear) and four-way control valve water pipe connector → Disconnect four-way control valve water pipe IV from battery pack → Disconnect battery pack inlet pipe assembly from battery pack → Remove battery pack ground wire connection bolt (10±0.5N·m) → Disconnect chassis harness assembly connector → Disconnect battery pack rear high-voltage harness assembly connector → Place platform jack and secure → Remove battery pack assembly-to-body mounting bolts (120±6N·m).

Installation: Reverse order + three mandatory actions—rewrite VIN, match SK, clear DTCs. Connector pull-back verification: After connector installation, use a force not exceeding 20N to pull the connector outward (do not pull the wiring harness). The connector should not come out, confirming proper insertion. Then re-insert the connector vertically to prevent poor contact caused by the pull-back.

On-Board Charger Assembly and Charging Socket

On-Board Charger (OBC): Disconnect negative terminal → Drain coolant → Remove manual service disconnect switch → Remove item box cover/body (rear)/trunk rear trim cover/battery inspection cover/vehicle tools → Disconnect fast-charge charging socket from OBC connector → Disconnect slow-charge charging socket from OBC connector → Disconnect OBC three-in-one harness from OBC connector → Remove positive terminal rubber boot → Remove positive terminal fixing bolt and disconnect positive harness (10±0.5N·m) → Disconnect battery pack rear high-voltage harness from OBC connector → Remove coolant hose clamp and disconnect hose → Remove ground bolt and disconnect ground wire (10±0.5N·m) → Remove OBC-to-mounting bracket fixing bolts and take out (25±2N·m).

Slow-charge charging socket: Fixing bolts 8±1N·m. Fast-charge charging socket: Ground bolt 10±0.5N·m, bracket fixing nut 10±1N·m, fixing bolt 8±1N·m.

High-Voltage Harness Family (Six Harnesses)

General procedure: Disconnect negative terminal → Lift and support → Remove manual service disconnect switch → Remove item box cover/body (front/rear), trunk trim cover, battery inspection cover, vehicle tools → Disconnect corresponding high-voltage connectors → Remove fixing nuts/bolts → Remove harness; installation is reverse of removal.

Electric Drive and Generator Controller

Front drive motor assembly (HW165): Disconnect negative terminal → Remove front subframe assembly → Drain coolant → Drain reducer oil → Remove manual service disconnect switch → Remove bellows assembly → Place battery PTC assembly with water hose aside and secure → Place water pump assembly with water hose aside and secure → Disconnect range extender controller outlet water hose → Support front drive motor with floor jack → Remove motor mount (left) assembly fixing bolts (70±4N·m ×3 mount grade).

Generator controller two-in-one assembly: After draining coolant, disassemble and assemble in order, torque 25±2N·m / 13±1N·m / 10±1N·m / 6±1N·m multiple grades. Vehicle Control Unit (VCU): Fixing 10±1N·m.

Key Parameter Quick Reference

Safety Warnings

• This article is for technical reference. High-voltage disassembly must be performed by professional technicians with battery expertise, an electrician's certificate, and Jinkang technical training and authorization.
• Three warnings: Do not wear metal jewelry, use insulated tools + gloves + shoes, and never operate bare-handed; carbon dioxide/dry powder fire extinguisher and goggles must be available on site.
• Fixed pre-sequence: Disconnect negative terminal → Lift and support → Drain coolant → Remove manual service disconnect switch (as applicable).
• When replacing the battery pack, VIN writing + SK matching + DTC clearing are mandatory; omission will cause anti-theft/energy management anomalies.

Repair Insights

The most practical aspect of this AITO M5 high-voltage disassembly chapter is the torque grade system—memorize by "connection object": body grade 120±6, mount grade 70±4, bracket grade 25±2, harness/ground grade 10±1/10±0.5, fixing grade 8±1, small component grade 6±1, six grades cover all high-voltage components. Compared with NIO/Changan manuals, AITO has three unique actions worth remembering: When replacing the battery pack, rewrite VIN + match SK—the battery pack is bound to the vehicle's anti-theft/energy management system; this is a direct failure point for "replace without programming"; Connector pull-back 20N verification—after installing the connector, pull back with a force not exceeding 20N (pull the connector, not the harness); if it does not come out, insertion is OK; this is a more quantitative criterion than a "click" sound; Use a floor jack to support the front drive motor—before removing the mount, support must be in place to prevent the motor weight from tearing remaining fixing points. Finally, remember the four-step general pre-sequence: Disconnect negative terminal → Lift → Drain fluid → Remove MSD. For battery-related chapters, every step cannot be skipped, especially "drain coolant" before removing the MSD—avoid touching water pipes while energized.

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【This article is for reference only】