Automotive Technology Course | OBD2 Repair Strategies 4

Automotive Technology Course | OBD2 Repair Strategies 4


[Music] [Music] [Applause] a major revision of the obd2 system was made in 2004 more than 76 P IDs or parameters are now supported previous OEM data is now part of obd2 as well as misfire counters this makes it possible to devise incredible Diagnostics features in a modern scan tool the ability to detect misfires Tides a specific sensor is very important obd2 is even calling through further changes the system is dynamic forever changing to keep up with technology ECM reflashing is now part of obd2 it is possible to reflash any newer vehicle and a few older ones with a generic tool [Music] however it is advisable to wait on a purchase of one of these units since the technology hasn’t fully been implemented yet software reflash are not free and have to be purchased through the manufacturer can poor controller area network protocol in use since 2002 and even earlier in European systems is now mandatory for all new vehicles sold in 2008 and up the camp protocol can go as fast as 500 megabits per second but it is up to the scan tool manufacturer to implement this feature such a faster obd to scan toulon graphing mode will allow it to behave as fast as an oscilloscope or graphing meter this makes for great glitch capture and give you the ability to pinpoint specific problems this feature is sometimes called high definition PID in spite of this always remember that scanners have their limitation they always output interpreted data or from component to ECM to software process and to the scanner [Music] the obd2 system is a request based diagnostic system as opposed to a packet eight output as explained before elsewhere in this video the first step in scan tool Diagnostics is to perform one complete parameter of retrieval and analysis it is useless to continuously get a full parameter of data stream all the time the obd2 system is a request based diagnostic system as opposed to a packet dated output since each PID has to be requested one by one it will slow the tool down quite a bit besides this was done with the idea that large amounts of data retrieval was not needed anyways unless AE NCARB was right and doing so the idea is to first get the bigger picture and second closing on the important parameters to help you solve your problem make use of any and all data stream troubleshooting help that you might have available to you some scan tools also have normal values troubleshooting videos code setting criteria and other types of help data complete integration with the data stream and information is the way of the future is it useless to have large amounts of data available to you without the right type of help [Music] an area where the faster can protocol his king with the correct scan tool is in testing the catalytic converter the first step is to get a textual or numeric style output again to get the bigger picture then zero in on the specifics it is important when testing catalytic converters to concentrate on the operations of the actual o2 sensor both front and back do a preliminary check one at a time in other words test your front and then your rear o2 sensor independently use the guidelines to test the o2 sensor found in this video and elsewhere in our video collection the idea is to let your mind process the data at a slower pace the rigors that a modern technician has to face is highly understated few other professions have to process such large amounts of data so let your brain come to terms with the information here on screen we can also see how a double graph of the front o2 sensors can immediately show a similar pattern use your knowledge to detect the faulty o2 sensor this type of data retrieval will quickly show you any imbalance of each Oh to sensor Bank and will also allow you to perform various other tests such as propane enrichment to be able to detect vacuum leaks and broken gaskets [Music] then after verifying the correct operation of the front and rear o2 sensors expand your vision and get multiple o2 sensor comparison [Music] here we can see all four o2 sensors being graphed as you can see two of the graph lines the blue and purple are barely switching this is typical of rear o2 sensors since their output is muffled by the converted operation an even more condensed graph shows the clear difference between front and rear o2 sensor this is why you should always try and get to see the bigger picture [Music] don’t concentrate too much on detailed graphing unless you’re trying to capture a sensor glitch a major revision of the obd2 system was made in 2004 more than 76 P IDs or parameters are now supported [Music] always remember that scanners have their limitation they always output interpreted data or from component to ECM to software process and to the scanner [Music] the possibilities when it comes to PID analysis are limitless another analysis that you can do is testing the EGR system using specific parameters again only a faster easy M and scan tool can do this type of test by using the TPS rpm map and EGR position if available you can pinpoint the EGR function in our vehicle a late model hand system from Ford we do have an EGR error parameter which goes a long way in helping us detect problems bear in mind that our cam ECM and scanner are quite fast so therefore every minor imperfection will be detected [Music] all modern EGR valves will not react as quickly to changes due to the inertia of the valve mechanism itself so the error PID will always swing up and down it is up to the ECM program to filter it as out and only concentrate on a recurrent fall in other words it is okay for the EGR error to swing up and down so long as it levels out of zero again this system is so fast that every small mechanical imperfection is also reported as a data output error [Music] another way to test the EGR system is to use the map parameter remember that every time the EGR opens a small vacuum change is detected this is why many modern systems use what’s called a boost sensor which is a small map sensor only for the purpose of testing the EGR system this is also while you may see vehicles with mass airflow and map sensors at the same time the manifold air pressure sensor is only used to test the EGR or to be used in an emergency in case of mass airflow sensor fails [Music] so by setting the scan tool in a high definition parameter mode and testing for a small drop of the map value you can know if the EGR valve is operating [Music] this test requires for it to be done a few times since it is sometimes hard to see [Music] again only a faster ECM and scan tool can do this type of test by using the TPS RPM map and a gr position if available you can pinpoint the EGR function [Music] also remember that the EGR valve is disabled during certain conditions and before or after certain operations such as when the engine is cold during and after a wide-open throttle when certain devices are turned on and so on so plan on it [Music] in our vehicle we can now see how the manifold pressure changes when the EGR is operated a slight pre-loading of the engine may be necessary beware of the stress placed on the transmission [Music] a final test worth mentioning is the use of the u-tube sensor parameter to test the o2 heater this is an easy test and it’s done with the key on and engine off make sure your vehicle is cold after starting the test watch as the o2 sensor value quickly declines to zero or full lean since there is only oxygen in the exhaust so as soon as the o2 sensor reaches its operating point or 600 degrees it will start outputting the right value after 1 minute or so if not then the o2 sensor heater relay fuse wires or even the ECM itself is faulty this is a fast and easy test to perform once the fault is verified concentrate on the actual problem and finalize with the proper manual testing you [Music] [Music] most six is an engineering mode that allows for fast proving your repair without running the monitors it was designed by the engineers to do just that prove their reflash software fast but the engineers decided to keep most Explorer themselves an example of mo6 would be a vehicle with an o2 sensor code a simple Glenn’s at the translated most sixth a tow would also tell you of other problems so long as it’s translated mo six is shown in hexadecimal numbers most six will always show TI the n-side for test and component identification each vehicle has different T IDs and sits for the same systems and components the trouble is that it is almost impossible to decode their hexadecimal output values in our vehicle in question a Glens at the translated T IDs and since will quickly show any other impending problem the same goes for proving to repair once done the T ID or guessed heidi’s shows specific systems such as eg ro2 sensor evap or converter and the CID or component test shows the specific sensor or actuator most six outputs shows the result of specific tests that are always running for every monitor that runs a series of smaller diagnostic tests up to 100 or more per system 10 to complete the newer the vehicle the more mode 6 tests available the output is always given in hex numbers with dollar signs at the beginning the hexadecimal number system is used because it has less digits and saves a lot of memory space a few digits times millions of operations as up and hex numbers are always signed with the dollar sign to differentiate them from decimal as seen here a normal scan tool can access these hex codes from mode 6 which are easy for the computer to understand but not the human brain so it is up to the scan tool to translate most 6 very few diagnostic scanners will decode most six due to the added cost of development in our last vehicle a glance at most six will help us in determining that no other coat will appear after the repairs this is a very common problem in modern diagnostics sometimes it is necessary to just run the monitors again as a final note most six has been identified as having major discrepancies right from the manufacturer the discrepancies are in the area where the Hoey mt IV and since don’t coincide with reality so it is also up to the scanner developer to fix these problems with mode six all it takes to verify repairs his performance short road tests and query mode six not everything will be done through mode six but it is a lot of help and technicians need all the help they can get the future of OPD – or Diagnostics is driven by environmental issues technology and government regulations obd three which is a superset of obd – but with wireless capabilities has been operational for many years already it is a more capable system with the capability for broad links and borrowing from many disciplines such as raising and space technology [Music] this simply points out that the Diagnostics world is going to see even more changes and will continue to be dynamic so prepare and plan for you [Music] you


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