Geometry C Electric Drive System (3-in-1) Diagnostics and Disassembly Guide

Fault Background

The Geometry C's electric drive system is an integrated 3-in-1 assembly: drive motor + reducer + motor controller (IPU, Integrated Power Unit) — the motor controller is mounted above the motor and reducer, with the motor and reducer sharing a housing, achieving compact size, light weight, and low cost through integration. Its control core is permanent magnet synchronous motor FOC vector control (Clarke/Park transform → current loop → SVPWM inverter). Key diagnostic values are systematic: battery voltage threshold 9–16V, controller low-voltage supply 4.74–5.26V, motor speed above 15500rpm reduces power, motor over-temperature Level1 69.5–83°C / Level2 83–95°C (power reduction range 65–95°C), fuse trio CF27 15A (interior), EF03 15A, EF18 7.5A (front compartment); after replacing the IPU, reprogramming + road test for at least 10 minutes then re-read DTCs for double confirmation. Disassembly/assembly is done as a complete "electric drive system with subframe assembly" lowered as one unit; subframe bolts 120N·m + 90° and replace with new bolts every time they are removed. This article organizes system principles, DTCs, diagnostic procedures, and torque specifications into a field guide.

System Composition and Control Principle

Routine Diagnostic Checks and DTC Reading

Four routine checks: ① Check for aftermarket add-on devices that may affect the motor controller; ② Check easily contacted components for obvious damage; ③ Check the exterior of the motor controller for water or foreign objects; ④ Check the motor controller high-voltage harness connectors for looseness and internal corrosion.

OBD rules: When the on-board computer detects a component fault, it illuminates the malfunction indicator lamp and stores a DTC; if the fault does not recur for 3 consecutive drive cycles, the lamp goes out automatically, but the DTC remains stored in memory. If the scan tool has communication errors, first perform a "swap test": connect to another vehicle — if it works, the original vehicle's diagnostic connector is faulty; if communication still fails, the scan tool is faulty.

IPU DTC Highlights (P1B Series Excerpt)

Motor Controller Power Supply Fault Diagnosis

DTCs: battery voltage too high/low, IGBT drive circuit power fault, IGBT logic and current sensor power fault, IPU CAN power fault; trigger condition is based on controller low-voltage supply — voltage below 4.74V or above 5.26V triggers the fault.

Diagnostic steps: Check IPU exterior and harness connectors → ON mode measure battery voltage: standard 9–16V (if not, replace battery or repair charging system first) → OFF mode check fuses: CF27 15A, EF03 15A, EF18 7.5A (if blown, repair circuit and replace with same rating fuse) → OFF disconnect BV11b, ON mode use multimeter to measure IPU power terminals → OFF disconnect BV11b measure ground circuit (standard resistance continuity) → Replace IPU (see below) → Reprogram and configure IPU → Clear DTCs with scan tool → Road test vehicle for at least 10 minutes → Re-read DTCs to confirm no fault codes output.

Disassembly/Assembly and Torque (Subframe Assembly as a Whole)

The electric drive system and subframe are removed/installed as an assembly; key points:

• Subframe 4 fixing bolts: torque 120N·m + 90°, must replace with new fixing bolts every time they are removed;
• Intermediate shaft universal joint and mechanical steering gear fixing bolts: 39N·m;
• Electronic water pump (70W) 2 fixing bolts: 45N·m;
• Electric drive system ground bolt: 23N·m;
• Other fasteners per manual torque table (130N·m / 210N·m / 240N·m / 18N·m / 8N·m / 34.5N·m levels);
• Electronic oil pump: remove 3 fixing bolts to take it off, install in reverse order;
• When removing, support the subframe with a jack; note the assembly is heavy, follow lifting safety regulations.

Safety Warnings

• This article is for technical reference only; electric drive system inspection must be performed by certified personnel per OEM specifications; readers unfamiliar with the procedure are strictly prohibited from performing it themselves.
• The motor controller is a high-voltage component; before disconnecting any high-voltage connector or measuring terminals, power down in OFF mode, and immediately insulate high-voltage connectors after removal.
• Subframe bolts are angle-torque fasteners at 120N·m + 90° and are single-use; they must be replaced after removal, never reuse old bolts.
• After replacing the IPU, programming and road test confirmation are mandatory; do not install and power up an unprogrammed controller.
• Assembly removal involves jacks and lifting equipment; improper operation can cause personal injury; follow lifting regulations.

Maintenance Insights

The most memorable aspects of the Geometry C electric drive manual are three sets of "numeric thresholds" and a "double confirmation" discipline. Numeric thresholds: battery 9–16V is the first gate for power diagnostics, IPU low-voltage supply 4.74–5.26V is the second gate (out of range triggers power fault codes), KL30 normal range 8.44–16.9V, motor 15500rpm triggers power reduction, over-temperature is graded by Level1/Level2 (69.5/83/95°C three memory points) — these values provide a basis for determining whether a fault is real. Fuse trio CF27 15A / EF03 15A / EF18 7.5A; for power-related codes, check these first, don't replace the IPU immediately. Double confirmation discipline: after replacing the IPU, "reprogram + road test at least 10 minutes + re-read DTCs" is mandatory; delivering the vehicle without a 10-minute road test means no verification — intermittent faults and incomplete programming are most easily missed at this step. For disassembly/assembly, remember one phrase: subframe 120N·m + 90°, bolts single-use — this is the most accident-prone torque point in the entire assembly operation.

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【This article is for reference only】