HELLA, the renowned original equipment (OE) manufacturer and system supplier, has more than 60 years of experience in the fields of electrics and electronics, stretching back to the introduction of the first flasher control units in 1957. Now an established supplier of innovative vehicle electronics globally, the company pioneered the 24 GHz radar sensor for rear end applications, paving the way for further automated driving functions, and was the first supplier to bring radar sensors into the aftermarket. This business segment now makes up 34% of its sales.

The HELLA electronics portfolio includes more than 45 product groups and covers vehicle functions such as emissions, comfort and safety. One of the company’s fastest growing aftermarket product lines is wheel speed sensors, or ABS sensors as they are otherwise known, reflecting the demand for replacements that come from independent workshops country wide.

Overview
Wheel speed sensors come in passive and active designs, but both are equipped with cables, with or without protective covers, in different lengths and with sensor angles at 90 degrees or straight.

Passive sensors
The wheel speed sensors are positioned directly above the impulse wheel, which is connected to the wheel hub or drive shaft. The pole pin, surrounded by a winding, connects to a permanent magnet whose magnetic effect extends to the pole wheel. The rotation of the impulse wheel and the resulting switching from tooth-to-tooth space brings about a change in the magnetic flow caused by the pole pin and winding. This changing magnetic field induces a quantifiable, or measurable, alternating voltage (AC) in the winding. The frequency and amplitudes of this AC voltage are in relation to the wheel speed, so inductive passive sensors do not require a separate power supply from the control unit. Since the range for signal detection is defined by the control unit, the amplitude level must be within a specific voltage range. The distance between the sensor and the pulse wheel is determined by the axis design.

Active sensors
The active sensor is a proximity sensor with integrated electronics that is supplied with a defined voltage from the ABS control unit. A multipole ring can be used as an impulse wheel while at the same time being integrated in a sealing ring of a wheel bearing and inserted in this sealing ring are magnets with alternating pole directions. The magneto-resistive resistors integrated in the electronic circuit of the sensor detect an alternating magnetic field when the multipole ring rotates. This sinusoidal signal is converted by the electronics in the sensor into a digital signal. It is then transferred to the control unit as a current signal using the pulse-width modulation method. The sensor is connected to the control unit via a two-pole electric connecting cable and the sensor signal is also transmitted at the same time over a power supply line. The other line is used as a sensor ground.
In addition to magneto-resistive sensor elements, nowadays Hall sensor elements are also fitted, which permit a larger air gap and respond to the smallest of changes in the magnetic field. If a steel impulse wheel is installed in a vehicle in place of a multipole ring, a magnet is also affixed to the sensor element. When the impulse wheel turns, the constant magnetic field in the sensor changes. The signal processing and IC are identical to the magneto-resistive sensor.

At-a-glance advantages
• Wheel speed detection from standstill that facilitates speed measurements down to 0.1 km/h, which is relevant to traction control systems as soon as the vehicle accelerates
• Hall sensors detect forward and backward movements
• The sensor is in design smaller and lighter
• The lack of impulse wheels simplifies the power transfer linkage
• Less sensitive to electromagnetic interference
• Changes in the air gap between the sensor and magnetic ring have no direct impact on the signal
• Virtual insensitivity to vibrations and fluctuations in temperature Quality and range

As wheel speed sensors are an integral part of the vehicle’s driving safety system, replacing a faulty sensor with one of OE quality should be the natural choice for the independent workshop and helpfully, HELLA provides the ideal solution with more than 340 12-volt part numbers, for multiple applications, including numerous models within the BMW and VAG line ups.
However, it's not just the passenger car sector to which HELLA’s range extends, as its 24-volt offering includes 48 part numbers that cater for several relevant truck, bus and trailer manufacturers, including BPW, DAF, Iveco, Kogel, Krone, Liebherr, MAN, Mercedes Benz, Renault, Scania, Schmitz Cargobull, Tata, and Volvo.

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Sensored!

With the growing demand for today’s vehicles to be more economical and environmentally-friendly while retaining performance, it is becoming more and more vital to fit the right sensors.

NTK lambda sensors are the No.1 choice of vehicle manufacturers (VMs) providing exactly the right sensor for every vehicle application.

They give:
Improved engine efficiency
Reduced emissions
Increased economy

The experience NGK has in supplying the VMs worldwide allows them to offer exactly the right sensor for every vehicle application with 986 part numbers giving 76 percent coverage of European vehicles.

NTK is also a leading supplier of other engine management
sensors including:

NTK Camshaft and Crankshaft Sensors – comprising more than 200 UK-specific part numbers with excellent UK vehicle parc coverage.

NTK MAF & MAP Sensors - A range of 87 NTK Mass Air Flow (MAF) sensors and 69 Manifold Absolute Pressure (MAP) sensors.

NTK Exhaust Gas Temperature Sensors – with 38 part numbers covering 33 million cars.

Technical Tips for NTK Lambda Sensors:

Lambda sensor positioning in the exhaust system has many descriptions throughout the automotive industry, which can differ from that read on fault diagnosis equipment. For ‘sensor 1’ it is also known as regulating, front, upstream, pre-cat or upper.
For ‘sensor 2’ they can be referred to by some as diagnostic, rear, downstream, post-cat or lower.

To aid factor selection and correct supply first time, a fault code relating to ‘sensor 1’ and ‘sensor 2’ are commonly referred to on the factors’ parts look-up systems as ‘front’ and ‘rear’ respectively. Referring to them as such can avoid delay and ensure correct
supply first time.

When recorded fault codes relate to the Lambda sensor heater control, suspect the entire circuit. To eliminate the sensor; check there is a resistance reading between the two Lambda sensor heater wires (most commonplace between many sensor manufacturers are the two white wires). No continuity confirms the element is broken. Ensure any reading is aligned within the VM’s tolerance.

Sometimes a fault code can be read that correctly relates to an issue with the Lambda sensor and replacing it can cure the issue. However, upon the removal of the sensor, closely inspect the inside of the connector for any oil contamination – however slight.
On some vehicle models it is known for an engine oil leak to allow oil to enter the wiring loom. This can then migrate to other areas of the loom via capillary action.

Sometimes fault codes are recorded for Lambda ‘sensor 2’ (rear). Garages sometimes say the sensor they need has more wires than the one supplied. NOx sensors always have more wires than a Lambda sensor and outwardly are very similar in appearance,
the Lambda sensor will be close by!

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Nissens Automotive Heater and Cabin Blowers

Nissens Automotive (Nissens) is an established aftermarket replacement parts supplier with decades of thermal management experience, across both the vehicle’s engine cooling (EC) and air conditioning (AC) systems.

Its comprehensive product range, all of which is manufactured to Genuine Nissens Quality standards, to provide independent workshops with premium grade replacement parts, which operate to the same performance levels as the original, gives them a premium quality aftermarket solution they can depend on.

Although often overlooked when servicing or repairing the heating, ventilation and air conditioning (HVAC) system, heaters and cabin blowers serve a crucial role, particularly for the comfort of the occupants. So, particularly before the winter season, it is advisable to include these two components during an annual check and, if either are in need of replacement, use only premium quality aftermarket products.

Heaters
The heater is an integral part of the EC system, but also contributes significantly to the climate system by ensuring the production of warm air to the cabin and is often located behind the dashboard or in the HVAC module.
Hot coolant from the engine block passes through the heater, warming the intake air blown on its surface by the interior blower and this can be forwarded into the cabin, which during cold days in autumn and winter, significantly improves safety by reducing the time needed to demist the interior surfaces of the vehicle’s windows.

Important info
• Scale that settles on interior surfaces and comes from the use of water instead of a proper coolant may block the heater core limiting the coolant flow. Sediment and grime from poor quality coolants, wrong coolant mixtures or residues of cooling system leak stops will also accumulate in the heater tubes limiting flow and reducing the heater’s operating efficiency.
• A worn-out or broken thermostat valve may restrict coolant flow and so prevent the heater from operating properly.
• Due to the damp environment in which it’s positioned, the heater is often exposed to corrosion, which may cause leakages.
• The lack of sufficient coolant caused by leakages (not just in the heater but from other components) will result in improper heater operation.

Blowers
The interior blower ensures the required amount of ambient air is drawn in through the intake and flows through the heat exchangers, i.e. the heater and evaporator. As it passes through the heat exchangers, the air can be either warmed or cooled and is distributed throughout the cabin by the blower which is typically situated in the HVAC module located between the cabin and the engine compartment.
The interior blower is potentially vulnerable due to its plastic elements that can sometimes be fragile and, being an electrical device, it is sensitive to failures within the vehicle’s electrical system.

Important info
• A clogged or defective cabin air filter can significantly reduce the blower’s lifespan.
• The most common reasons for interior blower problems stem from failures in the vehicle’s electrical system, restricted flow in the air intake system and improper handling during its installation.
• Blowers in vehicles used for commercial activities, such as taxis, coaches and buses etc., are often exposed to greater wear simply as a result of the mileage they cover and working hours they operate.

Genuine Nissens Quality
All of the company’s products are designed and manufactured to Genuine Nissens Quality standards, which means they are engineered to deliver high performance and durability as well as fitting perfectly when replacing the original part.
In addition, the ‘First-fit’ policy ensures hassle free installation as whenever they are required, additional components, such as nuts, bolts, clips etc, are supplied within the Nissens box.

Quality versus price
Although a cheap product might at first glance be appealing, for the reputation of the workshop and the satisfaction of the customer, quality must be the priority.
A replacement heater from Nissens will ensure workshops avoid issues such as a poor quality finish, limited heat exchange capacity and leakages and in contrast to cheap blowers that can generate noise and interfere with a car’s electronics or radio, Nissens  blowers ar comprehensively tested for durability and operating efficiency.
A poor quality blower can quickly malfunction and provoke expensive AC system failures, including compressor overload and breakdown, as no airflow through the evaporator means no, or limited, refrigerant state change, which leads to poor system performance and exposes the AC compressor to fluid intake/overload.
In addition, as replacing the heater/blower often requires the dashboard to be removed, the work is time consuming and therefore, expensive, so changing the original part to a low quality version is a false economy.

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All you need to know about Yuasa AGM and EFB batteries

With more and more modern vehicles featuring emissions reduction technology such as start-stop, battery replacement has become more complex and time consuming.

On vehicles with start-stop technology it is essential the battery is replaced with one of the correct technology and specification. If a vehicle is fitted with an AGM Start-Stop battery then the replacement must also be an AGM Start-Stop battery, The same applies to EFB products.

Most modern vehicles come fitted with a Battery Management System (BMS) which must be reset through the on-board diagnostics (OBD) port to tell the vehicle when the battery has been replaced. Failure to fit the correct battery or reset the BMS can cause issues such as battery failure and complete loss of start-stop functionality.

On many new vehicles, the battery is not fitted under the bonnet and locating it can take time. The replacement process can also take far longer than on standard ignition vehicles, with some vehicles requiring up to an hour and a half of work.

Yuasa’s Online Battery Lookup offers a simple solution to save you time and money Yuasa Battery Lookup

It is the industry’s leading battery lookup and will identify the correct battery for the vehicle, and provide a wealth of information including  battery location, estimated fitting time, reprogramming required and detailed fitting.

You can also check out the YMF range of Yuasa Batteries here - YMF Car & Van Batteries

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NOx Sensors Fault Diagnosis and Replacement

There are a number of methods used on Diesel Engines to reduce harmful emissions. One of these methods is called SCR (Selective Catalytic Reduction).

SCR is an active emissions control system where hot exhaust gases flow out of the engine and into the SCR system where aqueous urea (known as Diesel Exhaust Fluid, or DEF) is sprayed onto a special
catalyst.

Diesel Exhaust Fluid (DEF) is a non-toxic fluid composed of 32% automotive grade aqueous urea and purified water and is sometimes referred to as AdBlue.

The design of SCR technology is such that it permits nitrogen oxide (NOx) reduction reactions to take place in an oxidizing atmosphere. It is called "selective" because it reduces levels of NOx using ammonia as a reductant within a catalyst system. The DEF is rapidly broken down to produce the oxidizing ammonia in the exhaust stream.

The chemical reaction is known as "reduction" where the DEF is the reducing agent that reacts with NOx to convert the pollutants into nitrogen, water, and tiny amounts of CO2.

The component configuration of a SCR system can vary by the vehicle manufacturer, but the fundamental principle of operation remains the same. SCR systems are often used in conjunction with
a DPF filter.

In order to inject the correct amount of DEF into the catalyst, the system employs one or two NOX Sensors. The NOx sensors are fitted before and after the SCR catalytic convertor and may be
referred to as upstream and downstream.

The NOx sensors are required to accurately measure the amount of NOx in real time and feed this information to an ECU. This information in turn allows the ECU to accurately determine how much DEF needs to be injected into the catalytic convertor to produce the lowest emission.

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