Automotive Repair Library, Auto Parts, Accessories, Tools & Equipment, Manuals & Books, Car BLOG, Links, Index
Click to see larger image of mode $06 scan tool dataMode $06 is an advanced diagnostic mode within the onboard diagnostic (OBD II) system on 1996 and newer vehicles that keeps watch on how all of the sensors and other emission control components are functioning. It can only be accessed with a professional grade scan tool, and requires scan tool software that can convert the hexadecimal (16-bit computer code) into ordinary numbers and values. In other words, it is an advanced diagnostic mode that can reveal the inner workings of the OBD II system, and can tell you when a code is going to set even before it sets the code and turns on the Check Engine light. An inexpensive code reader or basic scan tool can't access or read mode $06 data.
Normally, most technicians ignore mode $06. On older scan tools, it was very difficult to access. And if they found it, the hexadecimal code looked like gibberish. You had to use conversion tables to translate the code into ordinary numbers, and you had to find the vehicle manufacturer's reference codes to decipher what each line meant. So it was a pain to use, and many technicians didn't even know it existed.
As time went on, scan tool manufacturers began to add software to their tools that made Mode $06 easier to find a use. Many professional grade scan tools now display all of the mode $06 data in plain English with units of measure for various types of data (pressure, temperature, etc.). Some will even flag in red values that are out of range, making it much easier to spot problems that may set a code.
The greatest value of mode $06 from a diagnostic standpoint is that it can verify repairs have fixed a problem without having to wait days for certain OBD II self-tests to run.
To make sure a vehicle's emissions do not exceed federal limits, the OBD II system runs various self-checks (called "monitors") while the vehicle is being driven. Some of these monitors are "continuous" and monitor certain sensors and systems all the time. Other monitors (called "non-continuous" monitors) only run after certain operating conditions have been met. Consequently, non-continuous monitors may be slow to complete their self-checks, and may not set a fault code for several days or even weeks after a fault occurs. So being able to verify a repair has fixed a problem without having to wait for the Check Engine light to maybe come back on is a god way for repair shops to reduce comebacks and unhappy customers.
Mode $06 is most useful for checking misfires on Fords, and for checking the catalytic converter and evaporative emissions (EVAP) system on most cars. The latter two are non-continuous monitors and can be very slow to complete depending on driving conditions.
A vehicle that has to take a plug-in OBD II emissions test will not be accepted for testing unless ALL of the OBD II monitors have run and completed. What's more, it won't pass the test if any fault codes are found in the powertrain control module (PCM) memory. So clearing any codes just prior to taking an OBD II test won't do you any good because your car will be rejected until all the monitors have run and everything has passed the self-checks.
Mode $06 isn't something your average motorist has ever heard of, and few do-it-yourselfers have the kind of professional grade scan tool or factory scan tool that is necessary to read the mode $06 data. But professional technicians who are up-to-speed on OBD II and are good at diagnosing emission faults should be aware of mode $06 and know how to access and use it.
How Mode $06 Data is Displayed
On older scan tools, all of the mode $06 data is in hex code with no units of measure defined. The data is listed in three columns:
* "TID" stands for Test identification. This is the sensor or component that is being monitored on that line.
* "CID" stands for Component identification. This is the test result for that sensor or component.
* PASS or FAIL in the last column indicates if the value is within range or out of range (less than the minimum acceptable value or greater than the maximum acceptable value for that sensor or component).
Translating Mode $06 Hex Code
If a scan tool does not translate the mode $06 hex code, tables that list the TID and CID definitions must be used to make sense of the data. Not all vehicle manufacturers publish their mode $06 information. Ford and GM's mode $06 information can be found on the vehicle manufacturer's service information websites, and on the International Automotive Technicians Network website (www.iatn.net).For GM Mode 06 charts, Click Here.
For Honda or Acura Mode O6 charts, Click Here.
Additional Mode 06 Diagnostic Information:
D-Tips.com
More OBD II Diagnostic Articles:
Check Engine Light OnBoard Diagnostics
Click Here to See More Carley Automotive Technical Articles
Check Engine Light On? Got a Diagnostic Problem and Need Help Now?
Be sure to visit our other websites: 