The ultimate guide to hybrid testing

The Ultimate Guide to Hybrid

The Ultimate Guide to Hybrid Testing

Hybrid testing and MOT testing of electric or alternative fuelled vehicles is perfectly simple when you know what to look for. In this article we are taking a look at the things you need to be aware of when testing alternative fuel vehicles.

Electric and hybrid vehicles are becoming more and more common these days. It is important that, as an MOT tester you are familiar with the basics. You will not need to examine the power systems of alternative fuelled vehicles. In many instances the MOT for an electric vehicle is simpler that for a petrol or diesel powered vehicle.

The following blog contains basic information about the layout of electric and hybrid vehicles. It is important to know this information if you are to perform a safe MOT.

Hybrid vehicle power train configurations

Different Electric Engines
Different Electric Engines

Carrying Out MOT Tests

You cannot refuse to carry out an MOT test on one of these vehicles because you’re not familiar with them.

Driving and Powering Down

– The biggest danger with hybrids and electric vehicles is that the vehicle may start to move off and cause injury or damage.
– You MUST know how to safely drive the vehicle and immobilise it.

If you are unfamiliar with the vehicle type, ask the customer to explain:
– The starting/moving off procedure
– How to make the vehicle safe

Also, check in the owner’s handbook.

Most vehicles have a ‘READY’ symbol on the dash which is usually green.

If the ‘READY’ symbol is lit, pressing the accelerator will make the vehicle move- whether the engine is running or not.

READY Button
READY Button

Powering Down
‘Powered down’ is the state in which the high voltage system is isolated and the vehicle can’t start up or move off.

If it has a conventional key, remove it to make the vehicle safe to inspect.

Most hybrids/electric vehicles now have ‘smart keys’ which usually have a start/stop button and key-less entry.

For safe hybrid testing follow these steps:
– Put the vehicle in ‘park’ with the parking brake applied.
– Shut the system off with the ‘start/stop’ button.
– Check that no warning lamps are lit.
– Remove the smart key from the vehicle and then store it at least 3 metres away – ideally further.

When You Need The Engine Running

For parts of the test when you need the engine running, simulate this by having the vehicle in ‘ready’ mode.

You will need an assistant for this, even if you’re using a one-person testing bay.

Make sure they:
– are fully briefed
– don’t touch the accelerator
– hold the foot brake on when carrying out turn plate checks

Risks From High-Voltage Systems

All electronically powered vehicles pose a theoretical risk because of the very high voltage used in these vehicles.

High voltage is defined as being more than 48 volts DC and 25 volts AC. The voltages in these vehicles are usually between 350 volts and 600 volts. THESE ARE LETHAL LEVELS!

Identifying Electric Cables and Components

The cables and some components are coloured orange so they are easily identifiable. This can extend to other components, e.g. air conditioning and power steering.

Orange cables

Managing Risk When Working With These Vehicles

Follow these simple precautions to keep the risk of electric shock extremely low:
– Assume high voltage battery and associated components are energised and fully charged
DO NOT interfere with the high-voltage system – no dismantling is needed when carrying out an MOT test.
– Abandon the test in the unlikely situation that any orange coloured cables or components are damaged or the wires are exposed – these are a potential shock hazard.
– Venting batteries also pose a risk in a confined environment.
If you have a pacemaker – consult your doctor before working with these vehicles.

Training and More Information

DO NOT carry out any repairs on high-voltage systems unless you’ve had recognised training for that type of vehicle.

Many manufacturers and trade associations run in-depth courses on these types of vehicles. You can get more detailed information from:
– Vehicle manufacturers
– Trade associations

For more information on MOT Juice MOT Tester training modules simply follow this link – MOT Tester Training – The Ultimate Guide


MOT Mock Exam

Think you already know the training curriculum off by heart?

Have a go at our free MOCK exam below, we challenge you to pass it first time!

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