Hybrid & EV
High Voltage (EV / Hybrid) Systems in Telford
High-voltage systems on hybrids and EVs are a different discipline entirely. The traction battery, inverter and drive motor run at hundreds of volts and demand trained, safety-led diagnosis. We work to manufacturer isolation and lockout procedures, read the HV control modules with the right tooling, and diagnose at the cell, inverter and isolation level — never by guessing at a £4,000 battery.
Common Symptoms
If you are seeing any of the following, it points to a high voltage (ev / hybrid) systems issue we can diagnose:
- Hybrid system warning, 'check hybrid system' or ready light won't come on
- Reduced EV range or the car running on the engine only
- HV isolation fault or ground-fault warning
- Traction-battery cell-balance or state-of-health codes
- Inverter or drive-motor warnings
- Charging faults — on-board charger or DC-DC converter codes
Common Causes
Faults like this rarely have a single cause. The usual culprits we find are:
- Loss of HV isolation — moisture, rodent damage or failed component
- Traction-battery cell degradation or module imbalance
- Inverter or DC-DC converter failure
- On-board charger faults affecting AC/DC charging
- HV contactor or pre-charge circuit faults
How We Diagnose High Voltage (EV / Hybrid) Systems
01We isolate and lock out the HV system to manufacturer procedures before any work begins.
02HV control modules are read with the correct tooling — not a generic OBD reader.
03Traction-battery state-of-health is assessed at cell level before a full pack is condemned.
04Isolation faults are traced methodically to the exact component, not a whole-system replacement.
Other Faults We Diagnose
Related Services
Next Step
Book in your vehicle.
Tell us about the symptoms you're seeing — we'll diagnose it properly with dealer-level tooling and come back with the next steps.