OBD Readers – help or hinderance?

 

In our modern technological world, vehicles have moved from being a simple construction that we remember our parents working on, to complex machines. With a dramatic surge in technology to improve our driving experience and increase safety, we are met with a mass of technological wiring and wizardry that only the likes of Harry Potter would feel comfortable working with.  So, how do we navigate our way around it and are there any simple devices to help us?  Let’s take a look at OBD Readers and how they may help us with today’s clever gadgetry.

 

WHAT IS AN OBD READER?

A cars ECU (Electronic Control Unit), also known as an Electronic Control Module, is the ‘brain’ of the car.  It controls several electrical systems or subsystems within the vehicle from fuel injection and cabin climate control to braking and suspension.  To do this effectively, cars are littered with electrical cables and sensors that inform the ECU that everything is ok or if anything needs adjusting.

When these systems go wrong, the ECU sends a fault code to the OBD and highlights an issue on the dashboard by way of an engine light, etc.  It is important that the error codes can be accessed to direct you to the cause of the fault.  An OBD (On Board Diagnostics) monitors and reports diagnostic trouble codes generated by the ECU.  This information is accessed by a link connector allowing external electronics (OBD Reader/Scanner) to retrieve data and interact with the ECU to diagnose issues and optimise performance.

 

OBD READERS

OBD Readers are wide and varied in quality dependent on what you need them for.

At the very basic entry level, you can obtain an OBD reader online for around £20 and it will read codes for you at a basic level.  At the next level, it will turn the code off.

Spend £2k on an OBD reader and you’ll obtain much better-quality deeper codes.  At £5-10k, you’ll get diagnostic codes specific to the car and wiring diagrams enabling the technician to track and identify which part he thinks could be causing the issue, he then tests his theory.  When correctly identified, he can obtain the part number to order a new one.  These machines also programme and operate ‘pass-through’,  enabling accredited independent garages access to the same information from the manufacturers.

Contrary to popular belief, not one of the above systems will be able to pinpoint the exact issue.  They usually produce a number of different codes and it is in the skill of the Technician to identify the cause of the problem.  They will often conduct further testing or remove parts to test the system, before the fault can be identified.

Some of the more sophisticated machines are able to perform ‘live feed’ tests.

For smaller repairs, it can be a quick resolve, on other occasions when it becomes more complex, it can take hours and often more than one technician to determine the right course of action.  It takes many years of gaining knowledge and experience to become a Diagnostic or Master Technician, to accurately diagnose these multifaceted machines.

 

PITFALLS OF SELF DIAGNOSIS

The largest pitfall here is the cost to your pocket!  In search of an easy or quick fix, some are tempted to seek self-diagnosis via cheap OBD readers or Google ‘mechanic’.  Let’s face it, the marketing can be quite convincing!

Here are a few examples we have recently experienced, where expert advice would have saved money:

 

Turning the light off

Some OBD Readers have the capability to turn warning lights off in the car.  To do this, all codes in the system are wiped out, making diagnosis more difficult and lengthier.

As explained above, the ECU flags the problem on your dashboard and sends a code to the OBD.  The light on your dashboard is telling you there is a fault in the car.  Turning the light off, masks the problem and the issue continues because it hasn’t been rectified, often becoming worse over time.

The repair went from a Nox sensor to an additional diesel particulate filter, more than doubling the repair cost, which was sadly entirely avoidable.

 

Wrong part identified

Some will be quite insistent that after googling they know the part that needs replacing and this is the only course of action they will accept.  We have even had people give part numbers for the replacement part or have bought the part ready to be fitted.

There are two issues with bringing your own part.  Often, the part won’t rectify the issue; the incorrect part was ordered, or the quality is compromised (it was cheap with good reason); and the majority of garages cannot fit customer supplied parts (they are not covered by insurance as there are so many counterfeits).  Any parts supplied and fitted by Redbourn Auto Solutions are covered by a warranty and can be exchanged if they are faulty or wrong.

A recent customer said they needed a £600 part fitted as identified by their OBD Reader.  However, after conducting our own diagnosis, it was a £20 pipe that was the issue and therefore a much lower bill!

A good garage will always want to conduct their own diagnostics to confirm the part you think needs replacing, actually does need replacing.  Sadly, some garages/mechanics will replace the part you are asking for without question, which can be hard on your pocket.

 

ARE OBD READERS A HELP?

Absolutely!  They are invaluable to garages who have the capability to interpret them.

As an individual, it may be useful if you are nervous of a trip to the garage.  It is nice to have back up to help understand what they may say to you, but it is worth keeping it in context.  An over the counter bought OBD is unlikely to identify the root cause of the issue, and you’ll still have the expense of the repair regardless of what it says.

Properly functioning electrics are essential.  If a light comes on, however tempting it may be to look for a cheap fix, they rarely are.  It is time to speak to an expert who may well be able to help you keep money in your pocket.

There is a reason garages spend so much on diagnostic equipment, and they will typically have more than one machine to optimise their capability for you.  If a garage could diagnose from a cheap OBD reader, it would.  Especially, with the government enforced financial constraints imposed recently!

Find a garage with properly trained Diagnostic or Master Technicians who are currently competent and who will find the fault for you quickly and accurately.  They can be like finding a needle in a haystack, so once you’ve found one you can trust, stick with them!

Google (or other search engines) are useful for finding bargain holidays, your nearest restaurant, or helping the kids with their geography homework.  Its not so good at diagnosing car problems!

 

At Redbourn Auto Solutions, we have 2 capable Diagnostic Technicians and a Master Technician.  We operate with 4 diagnostic machines and other testing equipment to ensure an accurate diagnosis.

 

If you are looking for peace of mind with quality and professionalism, come and give us a visit. 

You can book online here:  Vehicle Check in – Car servicing Redbourn Auto Solutions