OBDII

Since the laws governing the OBDII system require manufactures to supply only the bare minimum amount of data. An OBDII scan is an effective way to scan a vehicle for faults and affect a repair only 10% of the time. Many common repairs can be completed using this system; however, due to the complexity of modern engine control systems this is usually not case since less than 25% of the engine control module data is obtained.  Perhaps perpetuated by automotive parts retailers and repairs looking to get you in the door, it is an increasingly common misconception that these codes accurately identify the cause. Ultimately, the customer pays the price in the end, spending more time and money, trying to turn off the dash light.

 

For example, your check engine light illuminates while driving to work one morning, you pull into an automotive repair shop and they offer you a generic engine scan. The tool generates a po alphanumeric code, the repair shop then uses this to repair the fault, and you drive away happy.  

 

In some cases, the shop has replaced the correct component, more often, the MIL comes back on.  Once again, you drive to the automotive repair shop, they scan the car and the tool generates the same fault!

 

Now we have a bad situation the customer feels wronged because the repair did not correct the fault and the repair shop is wondering why the same component is flagging a fault when by OBDII standards the fault has been remedied.

 

MANUFACTURER SPECIFIC DIAGNOSTIC EQUIPMENT

Now let us look at the same situation, but the fault is diagnosed by a shop with the factory computer equipment from the manufacturer. The technician scans the engine control system and retrieves a different code and/or multiple codes from the engine control system. Code #1 is the same as the previous shop however Code #2 is for something entirely different.  The technician then follows the guided fault routine for the fault in question and as it turns out the original component replaced by Shop A was not the fault but a fault in a related system was causing the OBDII system to flag the original component as the fault.

 

 

OBDII HISTORY

In 1995, the United States of America passed a law requiring all vehicle manufacturers selling cars in the U.S.A.  To standardize onboard vehicle computers with a generic output code for faults effecting vehicle emission output.

Due to the global demand for reduced emissions, cars manufacturers had to create more complicated systems to control engine operation this required more electronic control than ever before.  Before 1995, manufacturers used proprietary data unique to that manufacturer to monitor and fault test these systems.

It became apparent that the environment that we were working so hard to protect could be adversely effected by these new technologies if the repair community lacked the ability to effectively communicate with these systems for fault diagnosis and global OBDII was born.