Tesla Model X High-Voltage Battery and Charging System Repair Guide

Fault Background

Tesla Model X high-voltage battery repair revolves around three key aspects: battery pack "capacity model" matching — when replacing the high-voltage battery, the capacity model must be verified (same model battery as a new equivalent part, part numbers such as 1014114-00-A/B, 1031043-00-A for dual motor, 1020422-00-A/B/C, 1028600-00-B), and the battery pack also contains two levels of high-voltage battery fuses: 630A/700V and 550A/700V; the "dual charger" structure of the high-voltage junction box — the box cover bolts x6 (5N·m) and mounting bolts x4 (5N·m), connecting to the main charger connector x5 and the second charger connector x2 respectively; and the Charger/Discharger Tool for charge/discharge maintenance — only technicians trained in high-voltage awareness may operate it. The tool communicates with the BMS, and the panel switches must be set to the indicated positions. The emergency stop switch is for emergency use only. This article compiles a reference guide for the high-voltage battery, junction box, charge/discharge procedures, and surrounding 12V battery/charge port disassembly.

High-Voltage Battery Assembly

• Capacity model indication: The part number reflects the battery capacity model, used for matching during high-voltage battery retrofit/replacement — compare the capacity of the battery being removed with the equivalent model (if no equivalent battery is available, select a new equivalent battery according to the manual's correspondence);
• Common part numbers: 1014114-00-A/B, 1031043-00-A (dual motor), 1020422-00-A/B/C, 1028600-00-B;
• High-voltage battery fuses: S3 (630A, 700V, MDLS) and S2 (550A, 700V, MDLS) two levels;
• Moisture barrier cover bolts (1018737-00?) used with 1025301-00-A, verify together when replacing the battery.

High-Voltage Junction Box (Removal and Installation)

1. Perform the vehicle electrical isolation procedure;
2. Remove the rear seat cushion frame;
3. Remove the bolts securing the high-voltage junction box cover (x6, 5N·m);
4. Warning: Measure the entire assembly to confirm no voltage before continuing;
5. Set the coolant hoses aside to expose the junction box bracket bolts;
6. Remove the bolts securing the high-voltage junction box (x4, 5N·m);
7. Disconnect the junction box from the second charger connector (x2);
8. Disconnect the junction box from the main charger connector (x5).

For dual-charger models (e.g., P85D), there is also a "high-voltage junction box to charger logic" harness part number (1024956-00?), and when disconnecting, match each label accordingly.

Battery Charge/Discharge (Charger/Discharger Tool)

• Only technicians trained in High Voltage Awareness may operate;
• The charge/discharge tool communicates with the BMS via the communication interface to perform charge/discharge maintenance;
• Set the front panel control switches to the indicated positions (note: do not set the domain to an incorrect value other than TESLA MOTORS);
• The tool includes a rectangular load bank connector for discharging the high-voltage battery;
• The emergency stop switch is for emergency use only and can immediately disconnect the tool contactors.

Surrounding Disassembly Torque Specifications

Charge Port - Single Phase: High-voltage inlet cover screws/clips (x2, 4N·m) → Remove and discard the high-voltage cable retaining bolts (x2) and all washers → Charge port cable clamp lower nut (6N·m) → Upper nut (5N·m).

Battery - Auxiliary - 12V: Body harness connector retaining nut (6N·m) → Battery positive terminal retaining nut (12N·m) → Battery fuse box retaining nut (6N·m) → Battery hold-down strap nuts (x2, 3.5N·m).

Drive Unit (same structure as Model S): Remove rear subframe → Use axle shaft extractor to remove half shafts → Crane bracket bolts (x3) → Motor front/rear mount nuts (90N·m) → Motor side mount bolts (x3, 22N·m) → Front/rear mount bolts (each 90N·m) → Lift out the assembly.

High-Voltage Cables: Cable ties (1022868-00?, with clips), shielding spring bands (6009178-00?, high-voltage cable to motor) restore according to labels.

Safety Warnings

• This article is for technical reference only. High-voltage system service must be performed by certified high-voltage technicians per OEM specifications. Readers unfamiliar with these procedures must not attempt them.
• The first step for all high-voltage work is the vehicle electrical isolation procedure; after opening the junction box cover, measure to confirm no voltage.
• Charge/discharge maintenance is limited to technicians qualified in high-voltage awareness; the emergency stop switch is for emergency use only and must not be pressed arbitrarily.
• Discard and replace one-time-use bolts and washers; when replacing the high-voltage battery, verify the capacity model and fuse ratings.
• Follow torque specifications per the manual: junction box 5N·m, 12V battery 3.5/6/12N·m, charge port 4/5/6N·m, drive unit 22/90N·m.

Repair Insights

The most valuable takeaways from the Model X manual are the three "matchings." First, capacity model matching — replacing the high-voltage battery is not a matter of "any same-platform battery will do"; the part number (1014114/1031043/1020422/1028600 series) directly corresponds to the capacity model, and installing the wrong capacity disrupts the vehicle's energy calibration. Second, dual-charger matching — the junction box connects to the main charger x5 and the second charger x2; for dual-charge models like the P85D, disconnection must follow labels one by one, and plugging into the wrong port is the most hidden fault source for these vehicles. Third, tool and personnel matching — charge/discharge maintenance can only be performed by technicians qualified in high-voltage awareness; the tool communicates with the BMS, and the emergency stop switch is for emergency use only. This protocol is completely different from the old practice of "anyone can connect a discharge unit." The torque specifications follow the Model S system: junction box 5, 12V battery 3.5/6/12, charge port 4/5/6, drive unit 22/90N·m.

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【This article is for reference only】