Alastair Shephard

Content Writer

Joseph Law

Bumper Content Writer

Modern cars are smart systems packed with tech to monitor and manage their performance.

An OBD port is a tool that lets you plug into your car's brain 

) and download data or view it live—a handy tool for mechanics and drivers to keep things running smoothly. 

The OBD port is a universal plug for all cars, but the software isn't always as standardised.

Today, we're discussing everything you need to know about these ports, including what they're used for and how you can test them.

An OBD (On-Board Diagnostics) port is a universal plug mechanics can use to run tests and diagnostics on your car’s computer. It’s simply the spot where they connect their equipment.

This is done to know the status of the car’s sub-systems, and it can even help you detect faults or maintenance problems before they arise. 

Will an OBD scanner tell me what’s wrong with my car?

Yes, an OBD scanner will tell you what’s wrong with your car. But it’s not always that simple.

OBD readings provide fault codes showing failed tests, but they don’t pinpoint exact issues or repairs.

Mechanics or savvy drivers interpret these codes to diagnose problems. If unsure, consult a professional mechanic.

An OBD port is used for plenty of reasons. Like most connections between computers, data can be transferred in both directions in an OBD port. This allows more than just the reading of stored error codes.

Here are three main ways an OBD port is used: 

Modern cars track data like engine temperature, RPM, and throttle position. With the right tools, mechanics and owners can access this info. 

Even a basic OBD reader shows details like coolant temperature, helping diagnose issues—such as ruling out a faulty throttle sensor.

When a fault develops, the ECU can detect the abnormality via the sensors above. In most cases, something like a misfire caused by faulty 

When a problem occurs, even intermittently, the ECU stores the details in its memory. Mechanics can access this as a code to help diagnose the issue.

Because the ECU defines the car and engine so much, many parameters can be modified to suit the driver or upgrade the vehicle.

With the relevant software, changes can be made, such as increasing the engine’s performance - also known as a remap - and tweaking the way the lights operate to be more convenient.

There are some consumer-grade options for doing this, such as 

To test your OBD port, check for damaged pins or cable breaks. You can also try another scan tool or connect your device to another car's OBD port.

If these tests prove fruitless, you might need to work with a garage. Their professional equipment will be able to tell why the port is not responding as it should and advise on how best to fix it

Only clear OBD error codes once the vehicle is repaired or road-safe, and consider noting the codes for future reference.

What is the difference between OBD1 and OBD2? 

The beauty of OBD systems is their standardised ports, allowing any car to connect with the same cable. This is much like USB works for phones and laptops.

Car tech was limited when OBD1 was introduced in 1981, so many features we now take for granted weren't yet standard. 

OBD2 was introduced in 1996 and included many more features. This new standard was developed to be future-proof, unlike OBD1, and is still used today. 

OBD2 was introduced in 1996, but not all manufacturers adopted it immediately. Many makers only introduced it due to legislation. 

The list below will help identify whether your car has an OBD: 

Remember, your car may have an OBD2 plug, even if made before these dates. 

You will usually find your OBD port under the dashboard, rather than the engine bay. 

Some cars will also hide it behind a plastic lid, which will be labelled “OBD.’ The best way to check your specific car is to read the user manual. 

Failing that, a quick search online will almost always help. 

Whether you need to read error messages, learn more about your engine, or satisfy curiosity, there are plenty of options for every budget.

These typically plug in via a cable and display basic error messages and system parameters such as engine temp, RPM, throttle position, ignition timing, and more.

They can't typically change any parameters, though, and are difficult to use to gather data whilst on the move.

For around £50-£100, you can get a more complex OBD scanner. 

 can change your car's lighting and mirrors, allowing auto-dipping mirrors when reversing. They can also display ECU error messages. 

These tools display error messages and often include diagnostic libraries, guiding you through troubleshooting with physical and digital tests. 

Many even connect to your phone or laptop via Bluetooth.

At the high end, professional scanners are designed for garages and mechanics, costing hundreds of pounds and offering access to manufacturer-specific software for customisation, like BMW and VW tools.

Due to the complexity of these systems, they are often used in conjunction with a laptop computer and sometimes need a certain amount of training to operate effectively. 

For more information on OBD tools, Tom’s Guide did a tremendous run-down 

Can you drive with an OBD tool plugged in?

Yes, you can drive with an OBD tool plugged in. This allows you to see information as your car drives. You can even clear OBD codes while driving.

However, you should use wireless devices like Bluetooth that connect to a smartphone to avoid cables in the footwell, as these are a safety hazard. 

Always have a passenger monitor the device, and never use a mobile device while driving.

What is the best OBD2 scanner for beginners?

If you're new to OBD scanners, start with a basic, affordable tool to learn about your car's OBD port before deciding whether to upgrade or consult a mechanic.

No. Though OBD2 is a universal standard, there is a chance that the scanner isn’t compatible with your vehicle. 

Always check whether your chosen scanner is suitable for your car before purchasing. 

Can you clear codes with an OBD2 scanner? 

Yes. An OBD2 scanner allows you to check diagnostic codes and clear internal codes when not needed. 

OBD ports are crucial for emergencies and monitoring your car's health.

Knowing the type and location of your OBD port can help you access vital information quickly, saving you time and money down the road.

, you can split repair costs into monthly payments with no fees and find local garages for professional OBD assistance.

Apply online for up to £5,000 and choose from 1,000s of trusted repairers. 

What is an OBD Port?

Was ist ein OBD-Anschluss?

For most of us petrol and diesel vehicles are all we’ve ever known. So, it’s no surprise that when faced with switching to a completely new fuel type it can feel a bit intimidating. 

Is the charging infrastructure in place? How much do repairs cost, and where can I find a reliable mechanic? To keep you in the know, we answer eight common electric vehicles (EV) questions. 

The first consideration when looking for an EV is the charging range. Some electrics travel further than others on a single charge, and this naturally increases the price. You’ll also need to consider if you want to go for a fully electric or a hybrid, which allows for both charging and refuelling. 

The answer to this comes down to the charging points in your area. If you decide to go fully electric, a home charging point is incredibly valuable. If this isn’t possible, make sure there’s a good number in your area or near your workplace. If you’re worried about the lack of access to a charger, a hybrid model might be the better option. 

If purchasing an electric vehicle is out of your price range, an alternative solution is leasing. An increasingly popular option for motorists, paying monthly allows those on lower incomes to afford the transition to electric. Often maintenance packages are available to help with repairs. Plus, if the vehicle is less than three years old you won’t need to worry about taking the vehicle for an MOT. 

A growing concern amongst drivers is the cost of the battery and at prices around £5,000, it’s no surprise this is a worry for some. If a replacement is required, unfortunately, there’s not much that can be done. However, this shouldn’t put you off. EVs generally come with a battery warranty for around 8 years or 100,000 miles. Most manufacturers guarantee the battery will last for 5 years. 

Charging at home is a far cheaper alternative to using public chargers, so it makes sense to have one installed. A dedicated smart charger is a much safer option than a three-pin plug as they have many built-in safety features and the smart, app-controlled nature of most chargers takes advantage of off-peak electricity tariffs. To get started all you need is a private parking space, such as a driveway or garage. A good charger supplier such as 

 makes the process easy with qualified installers. 

If you’re renting, it’s important to get permission from the landlord first. To help cover the cost, renters and landlords may be entitled to up to £350 from the 

Office for Zero Emissions Vehicles (OZEV)

To charge your electric vehicle you first need to find the charging port. This will look similar to a fuel cap but if you’re struggling, the location can be found in your owner’s manual. 

There are four main charging speeds you need to know about: slow, fast, rapid and ultra-rapid. Rapid and ultra-rapid are commonly found on motorways and the slower options are usually home chargers that make use of overnight charging. 

For mid-journey charging, it’s important to point out, that you will need to supply your own charging cable, so always keep one in the car. Plug your cable into the charging point, public chargers will require a payment, and wait for your vehicle to gain charge. 

If you move to a new property without a charger, it’s possible to uninstall the charger and take it with you. But it’s worth considering that the charging point could increase the property’s value and attract potential buyers. 

6. How do I recharge my EV away from home? 

If you’re planning a long journey, we recommend looking for charging points on your route first. You can check this on apps such as PlugShare, Zap-Map, and Charge Point. You’ll also be able to choose which has the best charging costs and plan your journey around your vehicle’s range. 

Most supermarkets and service stations have chargers, as well as some public car parks, restaurants, workplaces and hotels, but their charging speeds and prices vary so it’s always best to check first.

7. Will my usual mechanic be able to repair my EV? 

As more drivers make the switch to electric the number of garages that can repair them increases so it should be easy to keep on top of your vehicle maintenance. It’s possible your usual mechanic will be able to help to depend on the repair, but it’s always best to check with them before making a booking. If they can’t, you could book in with a specialist who should have the parts and know-how for any repairs you need. 

There are some ways EVs can even save you money. Currently, they’re exempt from road tax, however this is set to change in April 2025, when drivers will be required to pay the standard rate (currently £165 per year). In addition to this, energy supplies often have cheaper tariffs for EV charging and some public car parks offer free spaces for electric cars. For drivers who need to use on-street parking, some councils offer reduced or free permits.

Answers to 8 electric vehicle questions you probably won't have thought of 

In many ways, the electronic control unit can be considered the most important component in a modern car, through it all primary functions operate. Below we take a look at exactly what it does, and what issues it can cause.

The acronym ECU refers to a car's Engine Control Unit, there are many other control units in modern cars such as: 

As the name suggests, the ECU is a device that controls and monitors various parameters and systems in a car. The first ECUs were basic microprocessors that only monitored basic engine parameters such as 

With the advent of things such as electric windows and doors, reversing cameras and parking sensors, modern cars have multiple control units alongside the ECU, such as Body control modules, lighting modules and more. 

All of these fulfil the same function within their respective system, to control and display data about the car’s status, either changing parameters or displaying issues to the driver.

Modern ECUs control or read almost everything that happens in and around the engine. There is a plethora of sensors that report back and parameters, of which the ECU will regulate, monitor and take action. 

For instance, the ECU uses data from the engine on RPM, Ignition timing, fuel injection rates and exhaust gas composition, to detect whether the combustion is happening exactly as it should. 

In the instance of any faults, such as a misfire, the ECU will detect and make changes accordingly, whether that is to alter the ignition timing or display an error message to the driver. 

Other control units such as body-control units monitor the status of things such as bulbs, windows, door locks, wiper motors and more. Again allowing the car to display an error message to the driver. 

Typically a modern car will have around 4 different ECUs; including the engine control unit, body control unit, ABS control unit and alarm/immobiliser control unit. 

But luxury cars will often have even more than this, with some vehicles having a separate unit to control things such as infotainment systems, active aerodynamics and more. 

The most common cause of ECU damage, especially in the UK, is water damage. A lot of manufacturers mount the ECU near the passenger or driver footwell, as this is convenient for all the electrical systems whilst being protected from the elements. 

However, the elements can sometimes get into this area, as things such as car sunroofs, windows and windscreens can leak. The water can then run down into the footwell and damage the ECU. 

Another common cause of ECU damage is faulty or badly modified electrical systems, such as shorts and wiring issues. Jump starting incorrectly can also cause problems, as high electrical loads can be sent through the ECU. 

Some cars can suffer if the battery is left to drain to empty too often or for too long, damaging the ECU’s internal battery system. 

One of the main jobs the ECU does is control the fueling and ignition of the engine. On 

 cars, this means the ECU can increase or decrease the amount of fuel injected, and on turbocharged cars, the amount of turbo pressure is permitted. 

An ECU remap is the process of adjusting the parameters to which the ECU adjusts fueling, timing and turbo pressure to produce more power. They can also be adjusted to increase the efficiency of the engine if required. 

ECU remaps achieve the best results on turbocharged cars, where the horsepower can often be increased by more than 50%, but care should be taken to longevity and also any insurance, finance or servicing requirements when doing this.

In many cases, the ECU will be damaged beyond repair, but it’s always worth looking into specialist independent repair services. These often exist for more niche and rare collector cars, where replacement parts are not readily available. 

After an ECU has sustained damage, it will usually cause many issues with the running of the car, if the main ECU has been damaged in any way, it will often cause the car to fail to start completely. 

If it can be repaired, depending on the severity and complexity of the ECU, it could cost between £200 - £500 to repair.

If your ECU is damaged beyond repair, you’ll need to replace it with a like-for-like part. This can be expensive in certain circumstances. Complete ECU replacements can cost between £300 and £2,000 for the parts and labour. 

Whilst the parts can be quite expensive, in the region of £300-£600 for a regular car, the labour, speciality software, and tools required can often be the main cost. 

The main issue to be found is that many control modules on modern cars are digitally keyed to other parts of the car, such as immobilisers, ignition barrels, door locks and such. In some cases, an ECU needs to be sold as a set, alongside immobilisers and ignition barrels. 

If you need some assistance with covering the cost of an ECU repair, split the bill with Bumper, completely interest-free, and find a local service partner to carry out your repair.

has been writing about cars for over seven years and writing for Bumper for over two, blending his passion for automobiles with a talent for storytelling.

Joseph has written about engineering and cars for Autozilla, Komaspec, and several engineering manufacturers. When he's not writing or tinkering with one of his five cars, Joseph dreams of owning an Alfa Romeo 33 Stradale.

Electronic Control Units Explained

If your head gasket is blown, or if you think it's about to fail, you’ll face a head gasket repair cost of £550 to £1,700. 

A head gasket seals the engine to keep heat and pressure contained. If it fails, the engine can quickly lose performance or suffer serious damage

Understanding average head gasket replacement costs before requesting a quote helps you budget confidently and avoid overspending. Let’s begin with the UK head gasket repair costs.

How much does a head gasket repair cost? 

Full-head gasket repair in the UK can cost between £550 and £1,700. 

The amount typically depends on the region, type of car, and whether the engine has overheated.

A vehicle with an engine in any kind of ‘V’ arrangement, i.e. a V6 or V8, can cost considerably more, as they have two cylinder heads and two gaskets. 

In many cases, removing the heads is often easier with the engine out. 

Head gasket repair cost for different car brands 

Head gasket repair costs often depend on your car type. 

Here’s what UK drivers can expect to pay for a head gasket replacement for the following car manufacturers: 

As with manufacturer types, head gasket repair costs can vary across the UK, with labour rates and parts availability influencing the final price. 

Here’s a breakdown of estimated costs by location:

Gasket repair costs a lot due to the expertise needed to repair it. 

In car repairs, labour time drives up costs more than parts. A head gasket may cost £20, but replacing it requires extensive disassembly of the engine. The complexity of modern cars and their need for specialised tools or procedures make repairs even more expensive.

Gasket repairs can be unpleasant for your finances. But with Bumper, you can use

 to split the costs into interest-free instalments. 

There are different types of head gaskets. But, over time, head gasket designs have become more uniform, with most modern vehicles now using Multi-Layer Steel (MLS) gaskets.

Older types, now largely obsolete, include:

MLS gaskets feature up to five layers of steel and elastomer, coated with a specialised rubber finish. This construction allows them to withstand the high heat and pressure inside the engine, making them far more durable and reliable than previous versions.

You shouldn’t try to repair a head gasket yourself. An expert is always needed for this job! 

Here are the main steps mechanics will take when repairing your car. 

Are there any additional head gasket repair costs? 

There may be additional blown head gasket costs if your car has mechanical complications. To get an accurate quote, make sure your mechanic provides a very thorough examination.

The head gasket should last for at least 100,000 miles if the car is maintained well.

Some exceptions exist where manufacturers improperly specify the gasket materials. Still, more often than not, a head gasket will never need to be replaced if the car is maintained and cared for properly. 

What are the signs of a blown head gasket?

Driving with a blown head gasket can cause serious engine damage, so it’s crucial to recognise the warning signs early.

Milky oil usually indicates that coolant has leaked into the engine oil. This mixture forms a white, frothy substance.

It signals serious engine problems, like a blown head gasket, so you shouldn’t ever ignore it.

Can I drive my car with a blown head gasket? 

A head gasket can break in various ways, so the answer depends on the type of damage you have.

As a rule of thumb, avoid driving more than necessary. Overheating or significant coolant loss can dangerously overheat the engine and lead to other costly repairs. 

How long can you drive with a broken head gasket?

You shouldn’t drive at all, as a broken head gasket can lead to further damage and unsafe driving conditions.

If you must, you might manage short distances at low speed, but continued use will worsen leaks and cause overheating. Complete engine failure is another real risk.

Overall, it’s best to repair the gasket before driving the car further.

Can you fix a blown head gasket without replacing it?

Some temporary gasket sealants claim to fix a blown head gasket without replacement, but these solutions are short-term and unreliable. 

Realistically, they’ll stop minor leaks briefly, but the underlying damage and reason for the blown gasket remain.

For lasting repair and to avoid further engine damage, replacing the head gasket with proper mechanical work is the safest approach.

No. Replacing a head gasket is a complex, labour-intensive task that requires special tools and careful handling of engine components. More importantly, it needs mechanical expertise. 

Any mistakes can cause severe engine damage and more costly repairs. For most car owners, it’s safer and more reliable to have a professional handle the repair.

Head gaskets usually fail due to excess engine heat, often from a lack of coolant or poor engine care. Learn more below.

Without coolant, the engine overheats, warping the block and cylinder head and creating gaps that let high-pressure gases escape past the gasket.

Don’t over-rev a cold engine, as it can cause uneven heating, warping, or cracking. 

Keep RPM below 3,000 until the engine warms, about 1–2 miles for petrol and up to 4 miles for diesel.

Ignition or timing faults, often from a stretched or skipped cambelt, can disrupt the combustion cycle.

Valves may close at the wrong time, causing pre-ignition, excessive pressure, and eventual gasket failure.

Does a blown head gasket mean I need a new engine? 

This ultimately depends on the problem's severity and the cause of the gasket failure. 

If the head gasket failed due to engine overheating, the cylinder head and block should be inspected. Severe overheating often warps the head beyond reuse, and the engine block may also crack or warp, necessitating the replacement of these parts.

Is it worth getting a blown head gasket fixed?

Yes. Fixing a blown head gasket is usually worth it if the engine is in good condition. 

Repairing a head gasket restores performance and prevents further damage. Ideal if you want to keep your car on the road.

However, for older or heavily worn cars, repair costs may exceed the vehicle’s value. Assess your car’s overall condition before deciding on replacement.

If your head gasket blows, you can suffer significant damage and even complete engine failure.

Getting the gasket fixed as soon as possible is critical. Hopefully, this article has pointed you in the right direction and helped you estimate your head gasket repair cost. 

A head gasket repair cost can seriously ruin your week. But it doesn’t have to be catastrophic. 

you can split the cost of repairs into monthly payments at no extra cost. 

Head Gasket Repair and Replacement Cost Guide

Cambiar la junta de culata

Reparatur- und Ersatzteilkosten einer Zylinderkopfdichtung

With the cold winter months in full force, the slippery surfaces can be an absolute nightmare for some drivers. There’s no denying that heavy rain can make it much harder to navigate the road, yet some drivers are forced to go out in difficult conditions due to work or other commitments. To make sure that you can stay safe at all times, we’ve outlined our eight most practical tips for driving in heavy rain. 

1. Leave the house as prepared as possible 

If you know you might face more risky conditions on the road, you can do most of your preparation before leaving the house. 

The most important step is to ensure that your windscreen wiper blades, both front and rear, are functioning and operational. 

You should also check how much fuel you have, as driving at a slower speed, as you might do in the rain, increases fuel consumption. 

Lastly, use a 20p coin to check that your tyres are of the legal tyre tread depth, as a lack of grip is the absolute last thing you want while driving in rain. 

2. Fill up with fuel if you’re embarking on a longer journey 

If you’re going on a journey that’s longer than a trip to the shops or work, you should consider filling up with fuel before setting off. Rain is notorious for increasing traffic, and getting stuck in traffic is known to increase your vehicle’s fuel consumption. With your heater, lights and wipers all likely to be in full use for the entire journey, your fuel economy will be reduced much more than usual. 

3. How much slower should you drive in the rain 

As a rule of thumb, aim to leave about twice as much space in the rain – four chevrons apart on the motorway, for instance. 

Everyone knows to reduce your speed and leave more space between yourself and the car in front when it’s raining outside, but driving too slow can also be very dangerous when visibility is limited. 

If you lose control of the car and start to aquaplane, it’s a natural response to immediately brake or overcorrect the steering. However, it might be one of the worst things you can do. 

5. Stay on top of your visibility at all times 

You might want to put on an extra layer or two when getting dressed, as the best way to prevent mist on your windows is to switch on your air conditioning. Additionally, use your headlights when necessary and be aware of any large vehicles such as buses and lorries, as they will create large amounts of spray. 

6. If you break down, keep your bonnet closed 

While you might want to investigate the issue yourself, opening up your engine in torrential rain can cause significant damage to your electrical system. Instead, wait for assistance to arrive and allow them to judge the situation. With any luck, the rain will have calmed down by then. 

7. Use a low gear and high revs to get through any unavoidable puddles 

If faced with a large puddle that you can’t avoid on your drive, the best way to get through it is by keeping your car in lower gear while revving the engine. 

What does that actually look like? Let us explain: 

Exact advice varies by the size of the puddle, but driving in second gear is usually a safe bet. 

By doing so, you’ll be able to maintain the momentum of your vehicle and create a bow wave in the water to avoid getting bogged down. 

Once you’ve cleared the puddle, lightly apply the brakes in order to generate heat in the tyres and evaporate any remaining moisture. 

8. Be considerate to others using the roads 

If you’ve ever been unfortunate enough to get splashed by a vehicle driving through a large puddle while walking on the pavement, you know exactly how unpleasant it is. As part of staying alert to your surroundings while driving in heavy rain, try to also be considerate to others using the roads. This can include driving slowly through puddles near pedestrian areas, being patient with any cyclists who are also facing the adverse conditions and giving other drivers plenty of space on the road.

Advice

What is an OBD Port?

Answers to 8 electric vehicle questions you probably won't have thought of

Electronic Control Units Explained

Head Gasket Repair and Replacement Cost Guide

How To Drive In Heavy Rain Safely

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How Much Does It Cost To Change Brake Fluid in the UK?

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