Geely Geometry C High-Voltage Power Distribution System Fault Diagnosis and Disassembly Guide

Fault Background

The Geometry C's high-voltage power distribution system revolves around a core component: the high/low-voltage charging system (3-in-1: OBC + DC/DC + PDU). The manual describes it plainly as "similar to the fuse box in a low-voltage power supply system," responsible for charging the traction battery, distributing high-voltage DC from the battery to the motor controller, electric compressor, and PTC heater, and providing overload and short-circuit protection. On-site, three things matter: first, the fuse layout—compressor circuit 40A, PTC circuit 40A, 6.6kW OBC AC charging circuit 40A, 10kW OBC AC charging circuit 50A; second, the diagnostic framework for the seven high-voltage circuits—visual inspection → open circuit (continuity) → short circuit (>10kΩ) → insulation (1000V range ≥20MΩ) → component replacement → OBC reprogramming; third, two hard rules—before disconnecting the busbar, "wait 5 minutes, and only proceed if busbar voltage is below 36V," and for all connections, "one insert, two clicks, three confirmations." This article organizes the system composition, circuit diagnostics, and disassembly/assembly procedures into an on-site guide.

System Composition and Fuse Layout

The high-voltage power supply system provides energy from the traction battery to high-voltage components such as the motor controller, electric compressor, and PTC heater. It also includes a DC fast charging system and an AC slow charging system; all high-voltage components are connected and powered through the high-voltage power distribution system. Main components: high/low-voltage charging system (3-in-1), DC charging port, AC charging port, DC busbar.

Energy paths (per the manual):

• Driving discharge: Traction battery → DC busbar → high/low-voltage charging system → motor controller high-voltage cable → motor controller directly drives the drive motor (reverse path during energy recovery);
• DC fast charging: DC charging port directly receives power from the DC charging station, sent via high-voltage wiring harness to the traction battery (not through the OBC);
• AC slow charging: AC charging port → high/low-voltage charging system rectification → DC busbar → traction battery;
• Low-voltage supply: The DC-DC converter is integrated inside the high/low-voltage charging system, converting high-voltage battery power to vehicle low-voltage power.

All high-voltage cables are orange. Do not touch these cables or components when the vehicle is powered on; after disconnecting high-voltage cable connectors, immediately wrap them with insulating tape.

High-Voltage Connector Operation

• Type 1 HVP800 series: Use hand or screwdriver to gently pry the assist handle latch → handle disengages from the lock, slowly lift the assist handle upward, the connector withdraws accordingly → when the handle moves from horizontal to vertical, it is fully disconnected;
• Type 2 HVA280 series: Press the latch, then pull the connector outward until fully disconnected;
• For all high-voltage connectors, follow "one insert, two clicks, three confirmations" when connecting.

General Diagnostic Framework for Faults

Routine inspection four steps: ① Check for aftermarket devices that may affect the high-voltage power distribution system; ② Check easily accessible components for obvious damage; ③ Check the exterior of the high-voltage power distribution system for water or foreign objects; ④ Check high-voltage wiring harness connectors for looseness and internal corrosion.

Then follow the five-step diagnostic for each circuit (identical for all high-voltage circuits):

1. Initial inspection: Check components at both ends (e.g., socket, OBC, traction battery, compressor, PTC, IPU) for damage, deformation, contamination, or looseness; check wiring harness connectors for damage, poor contact, aging, or looseness → if abnormal, repair or replace the faulty part;
2. Open circuit check: Power mode OFF → disconnect connectors at both ends → use multimeter to test terminals → standard is continuity → if not, repair or replace the wiring harness;
3. Short circuit check: OFF → disconnect connectors at both ends → use multimeter to test terminals → standard resistance greater than 10kΩ → if not, repair or replace the wiring harness;
4. Insulation check: OFF → disconnect connectors at both ends → set high-voltage insulation tester to 1000V range → test each terminal to body ground → standard resistance 20MΩ or higher → if not, repair or replace the wiring harness;
5. Replace and finish: Replace the corresponding component (charging socket/OBC/traction battery/compressor/PTC heater controller/IPU) → confirm system is normal; after replacing the OBC, reprogram and configure the OBC.

Seven High-Voltage Circuit Connector Reference

Fault symptom table entry: DC charging circuit fault and AC charging circuit fault each follow independent diagnostic flows; other circuits are diagnosed per the corresponding sections.

Disassembly and Assembly Procedures

DC busbar assembly replacement: Disconnect the battery negative cable (follow the "battery disconnect warning") → remove the front compartment trim cover assembly → lift the vehicle → remove the power harness cover plate assembly → disconnect the DC busbar harness connector (at the high/low-voltage charging system side, insulate to prevent coolant from splashing onto the connector) → wait 5 minutes, then use a multimeter to measure busbar voltage; only proceed if below 36V → disconnect the DC busbar connector (at the traction battery side) → release the retaining clips and remove the busbar assembly. Installation: install clips → connect the traction battery side (one insert, two clicks, three confirmations) → connect the high/low-voltage charging system side (same confirmation) → install cover plate → lower vehicle → install front compartment trim cover → connect battery negative cable.

Electric compressor harness assembly replacement: Disconnect negative cable → lift vehicle → disconnect DC busbar (at high/low-voltage charging system side) → disconnect compressor harness connector 1 (at high/low-voltage charging system side) → disconnect connector 2 (at heater side) → remove harness clips → disconnect compressor side connector → remove assembly; install in reverse order, each connector with "one insert, two clicks, three confirmations."

PEU harness assembly replacement: Disconnect negative cable → lift vehicle → disconnect DC busbar → disconnect PEU harness connector (at high/low-voltage charging system side) → remove 2 fixing bolts of PEU harness assembly → remove 2 fixing bolts of bracket → remove assembly (low-spec models have additional fixing clamps, remove clamps first); install in reverse order.

Safety Warnings

• This article is for technical reference only. High-voltage power distribution system maintenance must be performed by certified personnel according to OEM specifications. Readers unfamiliar with such work are strictly prohibited from performing it themselves.
• High-voltage cables are orange; do not touch them when the vehicle is powered on; after disconnecting connectors, immediately wrap them with insulating tape.
• Before disassembling high-voltage components such as the DC busbar: disconnect the battery negative cable → wait 5 minutes → confirm busbar voltage is below 36V, all three steps are mandatory.
• High-voltage insulation testing must use a high-voltage insulation tester on the 1000V range; a regular multimeter does not meet insulation testing requirements.
• Before disconnecting the battery negative cable, read the "battery disconnect warning" section in the manual; operations require insulation to prevent coolant from splashing onto high-voltage connectors.

Maintenance Insights

The most valuable part of the Geometry C high-voltage distribution manual is a "five-step diagnostic template" that can be reused for any circuit: visual → open circuit → short circuit → insulation → replace and program. Remember three standard values to get the job done—open circuit requires continuity, short circuit greater than 10kΩ, insulation 1000V range 20MΩ or higher; also remember two operational details—power mode must be OFF and both connectors disconnected before testing, and after replacing the OBC, reprogram and configure it. Two "foolproof" designs worth noting: first, "one insert, two clicks, three confirmations", turning proper high-voltage connector seating into an audible and confirmable standard; second, "wait 5 minutes + busbar voltage <36V", providing a double safety threshold for DC busbar work—skipping this step to save time is equivalent to working live. The fuse layout is also worth memorizing: compressor 40A, PTC 40A, 6.6kW slow charge 40A, 10kW slow charge 50A—when a fuse blows, first check the circuit, then inspect the wiring harness.

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【This article is for reference only】