OBD readiness resetting when ignition is turned off

doug maire · #1 02-23-2009, 04:32 PM

Last week I had my bad rear o2 sensor replaced and afterward the shop erased all the obd error codes from the OBC. I then drove the car the necessary distance and time to restore the computer back to readiness for my emission test. When I tested at the emission station the informed me it failed and was "not ready" to be tested. So I drove around some more to make sure all the sensors had a chance to reset. The second trip to the emission satation yielded the same result. The third time I purchased my own OBD reader and kept it connected as I drove around until all the sensors were cleared. I then took it to the emission station the third time and just as before it failed, All the obd data had been lost again. As soon as I turn off the ignition I must be loosing power to the on board computer. It is acting the same as disconnecting the battery and resetting the obd. Has anyone experienced this problem.

SoCal LS-L · #2 02-23-2009, 06:03 PM

Quote:

Originally Posted by doug maire

Last week I had my bad rear o2 sensor replaced and afterward the shop erased all the obd error codes from the OBC. I then drove the car the necessary distance and time to restore the computer back to readiness for my emission test. When I tested at the emission station the informed me it failed and was "not ready" to be tested. So I drove around some more to make sure all the sensors had a chance to reset. The second trip to the emission satation yielded the same result. The third time I purchased my own OBD reader and kept it connected as I drove around until all the sensors were cleared. I then took it to the emission station the third time and just as before it failed, All the obd data had been lost again. As soon as I turn off the ignition I must be loosing power to the on board computer. It is acting the same as disconnecting the battery and resetting the obd. Has anyone experienced this problem.

What year is your car? If you have the OBDI they may have left the two prongs connected into the diagnostic harness, im not sure if that would matter or not. If your car is pre-1996 you should check behind your drivers side kick panel and make sure they are disconnected. The link on this is in the how-to documents on checking codes. The OBDI SVX has a self-test function.

doug maire · #3 02-23-2009, 06:32 PM

It is a 1996 SVX Lsi. It uses OBD2

an959 · #4 02-23-2009, 08:32 PM

do you have aftermarket alarm? usually it cutoff starter but might be ECU in your case...

doug maire · #5 02-24-2009, 07:21 AM

Factory installed alarm system.

Mike621 · #6 02-24-2009, 08:42 AM

NJ will not pass an OBD2 car if it has been 72 hours or less since last ECU reset (clearing the codes with a reader, etc).

Turning off your car will not neccessarily clear your ECU of codes.

doug maire · #7 02-24-2009, 09:44 AM

I finally got to the bottom of the problem. Apparently there are 2 tests that are performed on an OBD2 system. The first is a readiness monitor test and the second is the ODB sensor error test. The readiness test is to verify that all the sensors have run their system checks and have reported back to the OBD computer. The second test is to see if those sensors have recorded any errors from those sensors. The problem with the early Subaru OBD2 systems is that some were designed to cut off power to the OBD computer every time the ignition is turned off (which resets the readiness every time) or they have an extremely long drive cycle (as much as 1,000 mi), which prevents the readiness monitors from setting under a normal drive cycle. Unfortunately Arizona Emission Test requires that the ignition be shut off before conducting the readiness testing. As a result the OBD reports that the system is not ready and the vehicle fails. After 3 failed attempts I discovered that the AZ Dept of Transportation has a list of vehicles that have these design errors in their OBD systems and they exempt those vehicles from the readiness test. In Lieu of the readiness test DMV conducts a check engine light test to assure that the check engine light is functioning correctly.

kwren · #8 02-24-2009, 01:04 PM

Too bad the people that have only one function in life, showing up as they wait for their fat retirement and free medical that they will get for the rest of their life, have no clue what they are supposed to be doing for the rest of us.

On the outside chance some here "work" for the government, I am only talking about the rest of the people that "work"

for the government... not you!

Keith

doug maire · #9 02-24-2009, 01:20 PM

What is the relevance of your reply to the topic.

liamrh · #10 02-24-2009, 08:21 PM

Quote:

Originally Posted by kwren

Too bad the people that have only one function in life, showing up as they wait for their fat retirement and free medical that they will get for the rest of their life, have no clue what they are supposed to be doing for the rest of us.

On the outside chance some here "work" for the government, I am only talking about the rest of the people that "work"

for the government... not you!

Keith

Or go take some english classes before that nonsense falls out of your mouth.....besides it just being ****ing trash anyhow.

SoCal LS-L · #11 02-24-2009, 09:22 PM

Quote:

Originally Posted by liamrh

Or go take some english classes before that nonsense falls out of your mouth.....besides it just being ****ing trash anyhow.

I'll agree Keiths post came out of left field, but how appropriate is THIS response compared to the normal interactions of the people of the SVX World Network?

alltrac · #12 02-25-2009, 05:23 PM

A search of 1996 OBDII would reveal this thread http://www.subaru-svx.net/forum/show...ght=1996+OBDII