FAQ on the OBD Diagnostic System and Why a Diagnostic OBD2 Scanner is Needed

Starting out with the tool itself, a diagnostic OBD2 scanner is the appropriate tool to analyze and make diagnostic decisions based on the factors the scanner or reader shows on its display. The diagnostic OBD2 scanner is more versatile than an OBD2 reader because most professional landroverbar.com OBD2 scanners will give you the fault code with its descriptive meaning as opposed to a reader which only shows the fault code, which then has to be checked on a list of known codes. Most OBD2 scanners have the ability to read sensor voltages, save a ‘freeze-on-fault’ screen; this is very efficient and a big time-saver in OBD diagnostics, as multiple tests and screening till fault re-occurs are eliminated, gives in ‘real time’ emissions test status (smog testing for Federal compliancy), will reset the ‘Check Engine’ light and much more depending on the OBD2 scanner’s features and OBD interfaces. The OBD2 system is always being expanded in technology and new interfaces. Such new mandatory interfaces, which started in 2008 in the US are the CAN interface (Controlled Area Network). This system is used to communicate with different separate modules which are linked together as a network through the OBD interface. These communicate with the PCM (Powertrain Control Module) feeding it with constant specific data. The PCM then gives out commands according to the data it retrieved from these modules on particular tasks which need to be done and in what order and frequency (known as output).

What is OBD2 and what does it do in a vehicle?

OBD2 is On-Board Diagnostic (revision no.2), which means that the vehicle has an on-board self-diagnostic operational system, capable of maintaining itself and pinpointing out any initial faults. This fault detection may seem a nuisance at first when the MIL (Malfunction Illumination Light) ‘Check Engine” or ‘Service Engine Soon’ do come On for driver’s attention. Understanding that this indicator may save costly repairs in the future, if attended to immediately, one can only come to the conclusion that this is actually a benefit. The OBD software and the system package were created through a necessity in reducing air pollution and things have evolved from there. It was becoming impossible with the tougher Federal regulations to keep up with the traditional mechanical adjustments only, so electronic modules started being developed and implemented on fuel mixture and ignition, together with other secondary components.

What does a ‘MIL’, ‘Check Engine’ or ‘Service Engine Soon’ mean?

All these mean the same thing. These are warning indicators to inform a driver that something in the vehicle’s engine or emissions system is not functioning correctly. This warning should not be taken lightly and should be investigated accordingly before being driven any further. The only exception would be if this warning is intermittent. One has to keep in mind that there is the possibility of endangering other components like the catalyst if the fault is left unattended for too long. Take the habit of reading out all the instrumentation gauges present whenever you drive as these can give out early detection, specially the coolant temperature. When the Check Engine [http://www.diagnosticobd2scanner.com/obd-diagnostic/role-of-the-obd-ii-software-and-system] appears during driving the first thing to quickly visualize are these gauges. If one of these gauges doesn’t give a ‘normal’ reading then something severe may be on the pipeline. Stopping immediately is a must.

What is does CAN mean and what are its functions?

CAN stands for Controlled Area Network. This was introduced in the early 90’s on production vehicles and has evolved immensely since then. Combining the CAN system with the OBD interface has seen many much added safety and luxury features being included into the whole system. The CAN is subject to different modules (nodes) which although are separate modules for each system, they can be combined to work together. The CAN network communication is shared through a serial data bus. The power of the CAN system has pushed the envelope boundaries which were never dreamt before in automotive technology.

‘Check Engine’ lights up every time my vehicle is started. Is this a fault symptom?

This is actually designed purposely for two reasons and is not a fault if it goes out soon after (1-3 sec max depending on vehicle). First reason is to show that the OBD software is alive and functioning (not faulty) and also serves as a filament (bulb) and ‘MIL’ circuit test. Some vehicles can actually have a blown bulb or the ‘MIL’ circuit becomes damaged, or in the worst case scenario the OBD stopped communicating (engine probably will not run, depending on the fault).

If the ‘Check Engine’ goes On while driving what are the procedures?

There are two types of fault illuminations on this warning indicator. The worst one is the continuous illumination which preventive safety measures should be implemented immediately. This means coasting as quickly as possible to the side and stop engine immediately. Before doing so it is a good measure to check if the instrumentation gauges are reading out of range, both in coolant gauge and the oil pressure if installed together with any other warning signals. This gives a better picture of the fault for further analysis when the fault is being diagnosed later. Never attempt to drive with this type of continuous fault indicator. The second scenario is when this illumination warning is intermittent. This is less serious and can be driven for short distances until the repairs are done. However, prolonging this situation can cause more or other damage, which in return may turn into a continuous illumination. It is a wise decision to have the vehicle checked as soon as possible.

Will the light go Off if it is ignored and driving is continued?

This is an over-optimistic question and way of thinking, which unfortunately does more harm than good. Under normal conditions a fault is always a fault, and will remain one too. There are some rare occasions that the light does actually go Off (only when in intermittent mode) but this means that the fault has just been cleared out through the driving cycle. If the fault (damage) is real and is still there it will reappear sooner or later. Rare instances do occur when the management system adjusts accordingly through the complete drive cycle – but this is the exception to the rule rather than a normal occurrence. As a rule always have vehicle checked through with a compatible diagnostic OBD2 scanner to see what the flagged fault was. A reader might not be useful in such cases when the drive cycle has cleared the fault, as most readers are not capable of retrieving semi-cleared faults.

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