EV & Hybrid Diagnostics & Repair

Electric and hybrid vehicles use complex high-voltage systems, power electronics, battery management, electric drive systems and multiple interconnected control modules.

Voltcheck Motors provides professional diagnostics and repair for electric and hybrid vehicle electrical and electronic systems.

We diagnose the root cause of the fault before recommending component replacement or repair.

EV & Hybrid Diagnostics

We diagnose electrical and electronic faults across EV and hybrid vehicle systems, including:

• EV and hybrid warning messages
• High-voltage system faults
• Vehicle will not start or enter READY mode
• Reduced power or limited-performance warnings
• Charging problems
• High-voltage isolation faults
• HV interlock faults
• Battery management system faults
• Inverter and power electronics faults
• DC-DC converter faults
• On-board charger faults
• Electric motor and drive-system faults
• Cooling and thermal management faults
• CAN and communication problems
• Sensor and actuator faults
• Wiring, connector, power and ground problems

Diagnosis may include full vehicle scanning, live-data analysis, electrical testing, high-voltage system testing and vehicle network diagnostics.

High-Voltage System Diagnostics

High-voltage faults require correct diagnostic procedures and appropriate test equipment.

We diagnose:

• High-voltage system warning messages
• HV system activation problems
• High-voltage supply faults
• HV interlock circuit faults
• Contactor control problems
• Isolation monitoring faults
• High-voltage wiring and connector problems
• Control and monitoring circuit faults
• Problems preventing the vehicle entering READY mode
• High-voltage system faults following repairs or component replacement

The system is tested to identify the actual source of the fault before components are replaced.

High-Voltage Isolation Faults

Loss of insulation resistance can cause an EV or hybrid vehicle to disable the high-voltage system, prevent READY mode or generate serious warning messages.

Isolation faults may originate from high-voltage wiring, connectors, electric drive components, charging equipment, heaters, air-conditioning components or other HV-connected systems.

We provide systematic isolation-fault diagnosis to identify the affected circuit or component.

Charging System Diagnostics & Repair

We diagnose charging problems involving:

• Vehicle not charging
• Charging interrupted
• Charging warning messages
• AC charging faults
• DC fast-charging related faults
• Charge-port problems
• Charging communication faults
• On-board charger faults
• High-voltage charging circuit faults
• Charging control module faults
• Wiring and connector problems

Where the fault is within a supported repairable component or circuit, repair or replacement can be carried out following diagnosis.

On-Board Charger Diagnostics

The on-board charger converts AC charging power for use by the vehicle's high-voltage system.

We diagnose:

• On-board charger communication faults
• Internal diagnostic faults
• Power supply problems
• Charging control faults
• Cooling-related faults
• Wiring and connector problems
• Software and configuration issues

Replacement units may require programming, coding, configuration or initialisation depending on the vehicle.

DC-DC Converter Diagnostics

The DC-DC converter supplies the vehicle's low-voltage electrical system from the high-voltage system.

Faults can cause:

• 12V battery charging problems
• Low-voltage warning messages
• Electrical systems shutting down
• No-start or no-READY conditions
• Communication faults
• Repeated 12V battery discharge

We diagnose the converter, its control circuits and associated electrical systems before replacement.

Inverter & Power Electronics Diagnostics

Power electronics control the flow of electrical energy between the high-voltage battery and electric drive system.

We diagnose:

• Inverter fault codes
• Power electronics warning messages
• Electric drive control faults
• Communication problems
• Power supply and control circuit faults
• Cooling system faults affecting power electronics
• Wiring and connector problems
• Software or configuration issues

Supported external electrical, electronic and control-system repairs can be carried out where appropriate.

Electric Drive System Diagnostics

We diagnose faults involving electric drive and hybrid propulsion systems, including:

• Electric motor control faults
• Drive-system warning messages
• Reduced propulsion power
• Vehicle not entering READY mode
• Position and speed sensor faults
• Temperature-related faults
• Inverter-to-motor communication problems
• Wiring and connector faults
• Control module problems

Mechanical internal rebuilding of electric drive units is not part of this service.

HV Battery & Battery Management Diagnostics

We provide diagnostic assessment of the high-voltage battery system and its electronic controls.

This may include:

• Battery management system fault diagnosis
• Battery-related warning messages
• Battery voltage and temperature data analysis
• State-of-charge related faults
• Cell monitoring data assessment where available
• Contactor and pre-charge system diagnosis
• Battery communication faults
• Battery cooling system faults
• HV battery isolation-related diagnosis
• BMS communication and control faults

We do not currently provide internal high-voltage battery pack rebuilding or internal battery cell/module replacement.

Where an internal battery fault is identified, we can provide diagnostic findings and advise on the appropriate next step.

HV Interlock Diagnostics

High-voltage interlock circuits monitor the integrity of HV connectors, covers and components.

An interlock fault can prevent the high-voltage system from activating even when the main HV components are otherwise operational.

We diagnose interlock circuits, connectors, wiring and associated control systems to locate the source of the fault.

Thermal Management & Cooling System Diagnostics

EV and hybrid vehicles rely heavily on thermal management for batteries, power electronics, charging equipment and electric drive components.

We diagnose electronic and electrical faults involving:

• Electric coolant pumps
• Control valves
• Temperature sensors
• Cooling system control circuits
• Battery thermal management
• Inverter and charger cooling
• Electric cooling fans
• Communication and control faults

CAN & Communication Faults

EV and hybrid vehicles contain numerous interconnected control modules.

We diagnose:

• Modules not communicating
• CAN network faults
• Multiple simultaneous warning messages
• Gateway communication problems
• High-voltage module communication faults
• Intermittent network failures
• Wiring faults
• Power and ground problems affecting control modules

A communication fault can sometimes disable the entire propulsion or charging system even when the high-voltage hardware itself is functional.

EV & Hybrid Electrical Repairs

Following diagnosis, supported repairs may include:

• Electrical wiring repairs
• Connector repairs
• Power and ground circuit repairs
• Sensor replacement
• Control module replacement
• Charging system component replacement
• HV interlock circuit repairs
• Supported high-voltage component replacement
• Cooling and thermal management electrical repairs
• Electronic control system repairs

All repair work depends on the vehicle, system and nature of the fault identified during diagnosis.

Module Programming & Configuration

Replacement EV and hybrid control modules may require electronic setup before they can operate correctly.

Supported services may include:

• Module programming
• Coding
• Vehicle configuration
• Software updates
• Firmware recovery
• Initialisation
• Adaptations
• Basic settings
• Replacement module configuration
• System synchronisation

Availability depends on manufacturer, vehicle and control module.

Diagnosis Before Parts Replacement

EV and hybrid components can be expensive.

A fault code referring to an inverter, charger, battery system or control module does not automatically mean that component requires replacement.

The actual problem may be caused by wiring, connectors, cooling problems, low-voltage supply, communication faults, sensors, software or another interconnected system.

We diagnose and verify the fault before recommending replacement of expensive components.

Our Diagnostic Approach

Depending on the fault, diagnosis may include:

• Complete vehicle diagnostic scan
• Live-data analysis
• High-voltage system assessment
• Isolation resistance testing
• Low-voltage electrical testing
• Power and ground testing
• Wiring and connector inspection
• CAN network diagnostics
• Charging system testing
• Control module diagnostics
• Software and configuration checks

Once the cause has been identified, we explain the findings and recommend the appropriate repair.

Workshop-Based EV & Hybrid Service

EV and hybrid diagnostic and repair work is carried out at our workshop using appropriate diagnostic and electrical testing equipment.

Complex high-voltage, charging, isolation or intermittent faults may require the vehicle to be left with us for sufficient diagnostic time.

Diagnostic work is charged first. Any repairs, replacement components, programming, coding or additional work are quoted separately based on the diagnostic findings.