NGK Spark Plugs warns of surge in demand for MOTs

NGK Spark Plugs warns of surge in demand for MOTs

Mark Hallam, Marketing Manager at NGK Spark Plugs UK, urges factors to ensure their garage customers are prepared for a surge in demand for MOTs this month.

During the first national lockdown last spring, vehicle owners were granted an emergency six-month exemption on MOTs, as part of the ongoing fight against coronavirus.

However, the Government has not made any such announcement during the third lockdown, which means that if a motorist’s MOT is due to expire this month – which sees the introduction of the new 21 car registration plate – they need to book a test and take their car to a garage as normal.

March will consequently be a busy month for MOTs, and many thousands of vehicles will fail the test on emissions, which will lead to increased demand for the replacement of lambda sensors.

NGK is the world’s largest manufacturer of lambda sensors, and supplies a range to the UK aftermarket under the NTK brand name.

There are good reasons why we believe that NTK Lambda sensors are the number one choice of vehicle manufacturers (VMs) around the world; they are similar but different. The experience we have in supplying VMs across the world enables us to offer exactly the right sensor for every vehicle application.

Factor focus

Factors should encourage garages to always go with a bespoke OE-quality lambda sensor and steer well clear of ‘universal’ sensors. A ‘universal’ lambda sensor is designed to cover as many applications as possible by splicing in the connector from the unit being replaced. In theory, this sounds like a good idea, but in practice, the potential for a mismatch with the vehicle’s system, or subsequent premature failure, is very high.

With this in mind, factors can help to educate garages by ensuring they fit a new NTK Lambda sensor whenever they replace a vehicle’s catalytic convertor.


A worn or failed sensor can result in drastically reduced control of the fuelling system, which could result in increased fuel consumption, uneven running, generally poor performance, or failure of an MOT emissions test, so replacement is good news for the motorist, the garage and the factor.

We recommend that the function of the sensor is checked every 20,000 miles or annually. The emissions check as part of the current MOT test samples the exhaust gases to monitor the efficiency of the engine, exhaust system and engine control systems. The lambda sensor is a vital part of this system, and its function is therefore influenced by many other components.

A malfunction of an associated part may directly impact the performance of a sensor. An oscilloscope and gas analyser is a much more accurate way of assessing sensor performance than relying on fault codes alone. Garages need to look for slow response times, output range and heater function.

Contaminants from poor quality oils and fuel which remain in the exhaust gases can become deposited on the sensor element, affecting its operation. Even coolant from a leaking head gasket can reach the element.

For more information on the NTK range of lambda sensors, click here.

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