How to check an electric car or hybrid before buying in Germany

How to check the high-voltage battery and SoH

To assess the condition of the high-voltage battery you need more than a quick test drive around the block. A simple first step is to ask what range the owner gets in everyday driving and compare it with the factory figure. However, for a serious purchase you should read data directly from the BMS via OBD.

For many popular models there are dedicated apps and tools:

• for Nissan Leaf – LeafSpy;
• for Tesla – Scan My Tesla or built-in service menus;
• for other EVs – brand-specific apps or universal tools that can read BMS data.

These tools connect via Bluetooth or cable and show you much more than the dashboard ever will: voltage and temperature of individual cells, balance between modules, number of fast charges, recorded faults and more. This allows you to see the real SoH and spot weak or overheated modules in time.

Do not blindly trust range estimates on the cluster – they can be optimistic, averaged or even reset by software updates. If the deal is substantial, consider a professional EV health check: some specialist workshops and EV clubs in Germany run dedicated battery tests based on OBD data and controlled load cycles.

Hybrid-specific issues: pumps, cooling, 12V system

On hybrids you have to look not only at the traction battery, but also at the components that tie the electric and combustion sides together. Toyota Prius, Lexus, Honda hybrids and others each have their own “classic” weak spots.

• The auxiliary coolant pump for the inverter (electric coolant pump) is a known wear item. If it fails, the inverter may overheat and suffer expensive damage. Preventive replacement around 100–120 000 km is often recommended.
• Coolant should be replaced according to schedule (typically every 4 years). Old fluid means higher risk of corrosion and pump or inverter issues.
• Do not ignore the 12 V system: even though the car moves thanks to the high-voltage pack, the 12 V battery powers the control units and relays. A weak 12 V battery can cause strange errors and no-start situations.
• Inspect the high-voltage cables and connectors for corrosion, mechanical damage or amateur “repairs”. This is not only a safety issue but also an expensive one.

During our mobile inspections in Hamburg and the surrounding region we always pay special attention to these hybrid-specific points – overlooking them can turn a “cheap” hybrid into a very costly project shortly after purchase.

Servicing, brakes and tyres on EVs and hybrids

Ask for full service records. For electric and hybrid cars, the following items are especially important:

• oil or fluid changes in gearboxes / reduction drives (where applicable);
• brake fluid changes and cabin filters (and, on some models, coolant for battery or power electronics);
• condition of the brake system and tyres.

Because EVs use regenerative braking, pads and discs often last longer than on a conventional car. At the same time, if the car is mostly driven in the city and hardly ever brakes “hard”, the discs can rust badly. So it is not enough to look at pad thickness – the friction surface of the discs matters too.

Tyres deserve a closer look as well: tread depth on all four corners, age, correct load and speed rating. Uneven wear (for example heavily worn inside edges at the rear) may indicate chassis or alignment issues – sometimes a hint that the car has taken a knock in the past.

Software and typical EV risks

Modern electric cars are rolling computers. For brands like Tesla, the software part is just as important as the hardware. Before you buy, make sure the digital side of the car is healthy.

We recommend checking:

• whether over-the-air updates work and if there are any error messages or warning lights on the dashboard;
• whether there are open recalls or service campaigns (you can usually check this by VIN);
• whether there are stored critical errors in hidden or service menus – overheating events, high-voltage faults, charging problems.

Combine this with a “classic” used-car check and you get a complete picture of the vehicle. Key risk factors to look for include:

• damage to the battery pack housing (scrapes from curbs, impacts, traces of off-road use);
• water damage – a little moisture is usually fine, but a car that has been standing in deep water can suffer from severe corrosion in wiring and connectors;
• hidden accident damage: insurance and VIN databases, which we discuss in more detail in our article “How to read a VIN report in Germany”, can be very helpful here.

If you invest time in a thorough pre-purchase inspection of an EV or hybrid, you dramatically reduce the risk of buying a car with a tired battery or invisible electronic problems – and you give yourself the best chance of enjoying the “electric” experience instead of fighting expensive repairs.

OBD diagnostics of EVs and hybrids with Launch X-431

For modern EVs and hybrids, computer diagnostics are not “nice to have” – they are essential. An OBD scanner can talk to the control units that look after the battery, power electronics and charging system. Many of these faults will not show up during a short test drive.

Even if the car feels fine on the road, error codes in the inverter, BMS or charging system may already be logged. That is why experienced diagnosticians use professional tools such as LAUNCH X-431 with extended support for so-called “New Energy” vehicles.

Main modules and parameters to check

When connected to an EV, the scanner should talk to at least the following modules:

• 💯 BMS (Battery Management System) – the brain of the traction battery. Here you see cell voltages, charge and discharge currents, SoC, SoH, balance between modules and sometimes even the number of fast-charge sessions. The HV Battery Health function helps you judge how much life is left in the pack.
• 💯 Inverter and electric motor (powertrain control) – monitors temperatures, fault codes in the power electronics and motor behaviour. Abnormal current draw or temperatures are a red flag.
• 💯 On-board charger – you want to be sure the AC charging system works without faults and does not overheat.
• 💯 HV climate controllers – on many EVs and hybrids, heating and cooling systems are high-voltage consumers. OBD helps check compressors, pumps and battery thermal management.
• 💯 Standard safety systems (ABS, SRS, steering) – like on any car, you want no active faults in ABS, airbag or electric power steering modules.

Launch X-431 EV Kit and special functions for “green” cars

Standard OBD readers are quickly out of their depth on EVs. This is where specialised tools such as the LAUNCH X-431 EV Kit come in. Combined with the base X-431 unit it is designed to work with electric and hybrid vehicles out of the box.

The EV Kit adds several key functions:

• reading detailed data from each battery cell or module;
• monitoring temperature and voltage across the pack;
• direct communication with the high-voltage battery via the correct adapters and protocols.

In practice this means the tool shows you how evenly the battery modules are charged, whether there are hot spots and if any part of the pack looks suspicious. Advanced X-431 versions also include dedicated HV battery tests (HV Battery Health Detection) for hybrids and EVs from Toyota/Lexus, BMW, Honda, Mitsubishi and others.

In many ways this comes close to what a dedicated battery test bench does – but in a mobile, workshop-friendly form.

Practical workflow with Launch X-431 on an EV / hybrid

A typical diagnostic session looks like this:

• plug the scanner into the OBD port;
• select the correct make and model, then open the New Energy or Electric Vehicle section;
• scan all relevant modules – Battery, Inverter, Charger and so on;
• review live data: SoC (state of charge), SoH (state of health), 12 V system voltage, temperatures, charge and discharge currents, etc.;
• note any deviations from normal – for example, a large imbalance between modules, cooling system faults or HV warnings. These findings are powerful arguments in price negotiations or a reason to walk away.

Don’t forget the humble 12 V battery: a tired auxiliary battery can trigger a whole “Christmas tree” of warning lights. X-431 also shows the 12 V voltage and, with an additional module, can perform dedicated battery tests.

Conclusion: full diagnostics of an EV or hybrid before buying

Electric and hybrid cars reward careful owners – but they punish buyers who rely only on a glossy advert and a short drive around the block. Using a professional OBD scanner such as Launch X-431 with EV Kit allows you to inspect the car on a completely different level: not only the body and interior, but also the high-voltage system and all the control units.

With the right tools you can spot hidden defects in the battery, charging system or power electronics long before they become visible on the dashboard. This significantly reduces the risk when buying a car in Germany – whether in Berlin, Brandenburg or further north in Hamburg and the surrounding area, where we also offer on-site inspections.

A sensible strategy for buyers:

• start with a VIN report (CarVertical / CARFAX) to understand the history of the vehicle;
• follow up with a live inspection, professional OBD diagnostics and a proper test drive;
• compare history and real condition – and if something is unclear, bring in the Sicher-Check team.

This way you get maximum transparency and choose an EV or hybrid that will serve you reliably instead of draining your budget with unexpected repairs in the first year.