Complete/Incomplete OBD dianostic test issues....
Thread Starter
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
Complete/Incomplete OBD dianostic test issues.... I had my car tuned to the point that all my tests had been showing complete for many months. Then, I had my battery disconnected for an unrelated issue. The battery was plugged back in about 150 miles ago, but so far only *some* of the tests have gone back to a complete state. I should also add that of those 150 miles or so, 50 of them were in one long expressway trip. So my question is, does it take longer for some tests to complete than others? At my current low mileage since the battery disconnect, is that the likely reason why all the tests are not yet complete? I have only 4 tests showing incomplete at this time.
I didn't make any changes to tuning or mechanically that would effect this, and I have no SES, no pending DTCs, and no stored DTCs.
Please advise. Thanks.
I didn't make any changes to tuning or mechanically that would effect this, and I have no SES, no pending DTCs, and no stored DTCs.
Please advise. Thanks.
Thread Starter
Joined: Nov 2001
Posts: 34,643
Likes: 2,571
From: Schiller Park, ILL Member: #317
Originally Posted by WS6FirebirdTA00
disconnecting the battery or clearing of any codes will cause the pcm to relearn all information and may take up to 250 miles 
Also, is it not true that the 'type' of driving over these miles matters? I remember once seeing a list of parameters to complete an OBD drive cycle, and some of them involved a certain amount of warm starts, cold starts, run time, speeds, accels, deccels, etc.
So I guess it's possibile that it could take quite a while if most of the miles driven were at a constant speed on an expressway trip, correct?
Hey ryan remeber when I had to do the cycles I cant find the page right now but you have to do X amount of like 20-55mph and stay at a constant of 55mph or higher for like 4 miles and also it has to go through three cold starts where it reaches operating temp before you even move the car Ill try to find the link
Ok i got it
1.) Cold Start. In order to be classified as a cold start the engine coolant temperature
must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature
at startup. Do not leave the key on prior to the cold start or the heated oxygen
sensor diagnostic may not run.
2.) Idle. The engine must be run for two and a half minutes with the air conditioner on and
rear defroster on. The more electrical load you can apply the better. This will test the
O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved,
Fuel Trim.
3.) Accelerate. Turn off the air conditioner and all the other loads and apply half throttle
until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge
Flow diagnostics will be performed.
4.) Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During
this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim
diagnostics will be performed.
5.) Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
6.) Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will
perform the same diagnostics as in step 3.
7.) Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes.
During this time, in addition to the diagnostics performed in step 4, the catalyst
monitor diagnostics will be performed. If the catalyst is marginal or the battery has
been disconnected, it may take 5 complete driving cycles to determine the state of
the catalyst.
8.) Decelerate. This will perform the same diagnostics as in step 5. Again, don't press
the clutch or brakes or shift gears.
1.) Cold Start. In order to be classified as a cold start the engine coolant temperature
must be below 50°C (122°F) and within 6°C (11°F) of the ambient air temperature
at startup. Do not leave the key on prior to the cold start or the heated oxygen
sensor diagnostic may not run.
2.) Idle. The engine must be run for two and a half minutes with the air conditioner on and
rear defroster on. The more electrical load you can apply the better. This will test the
O2 heater, Passive Air, Purge "No Flow", Misfire and if closed loop is achieved,
Fuel Trim.
3.) Accelerate. Turn off the air conditioner and all the other loads and apply half throttle
until 88km/hr (55mph) is reached. During this time the Misfire, Fuel Trim, and Purge
Flow diagnostics will be performed.
4.) Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for 3 minutes. During
this time the O2 response, air Intrusive, EGR, Purge, Misfire, and Fuel Trim
diagnostics will be performed.
5.) Decelerate. Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 32km/hr (20 mph). During this time the EGR, Purge and Fuel Trim diagnostics will be performed.
6.) Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will
perform the same diagnostics as in step 3.
7.) Hold Steady Speed. Hold a steady speed of 88km/hr (55mph) for five minutes.
During this time, in addition to the diagnostics performed in step 4, the catalyst
monitor diagnostics will be performed. If the catalyst is marginal or the battery has
been disconnected, it may take 5 complete driving cycles to determine the state of
the catalyst.
8.) Decelerate. This will perform the same diagnostics as in step 5. Again, don't press
the clutch or brakes or shift gears.
Thread Starter
Joined: Nov 2001
Posts: 34,643
Likes: 2,571
From: Schiller Park, ILL Member: #317
Thanks Chris! 
I know I've missed a few of those. I think I need to do some of the coasting stuff and such. The tests I have not complete yet are EVAP, O2 heater, Catalyist, and one other I can't recall....
I know I've missed a few of those. I think I need to do some of the coasting stuff and such. The tests I have not complete yet are EVAP, O2 heater, Catalyist, and one other I can't recall....
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