OBD II code reset question
manicmech
12-29-2008, 04:14 PM
We took our 2001 SL2 in for an emission test and it failed via codes P0341 and P0442. I replaced the spark plugs and wires, and the fuel cap. I then disconnected the battery to clear the codes. Now the emission test station says they cannot retest because the "readiness monitors" were not resetting. We have driven it about 270 miles, including city, highway, etc. Shouldn't that be enough? We called a Saturn dealer and they were absolutely no help, saying we needed to bring it in for a $95 diagnostic test. Are a certain number of starts required, or is it based on mileage, or what? Thanks for any help you can offer.
RC1488
12-29-2008, 04:56 PM
OBD-II Driving Cycle
If you have a 96 or newer vehicle (http://www.saturnfans.com/forums/showthread.php?t=122994&highlight=drive+cycle#) you have the OBD-II diagnostic system. This system is constantly monitoring the sensors and solenoids on the engine. If you have replaced the battery, disconnected the battery or cleared the codes after making a repair you will need to do what is called a "Driving Cycle". This will perform a diagnostic on all the systems the computer monitors. This cycle can be done in under fifteen minutes.
To perform an OBDII Driving cycle do the following:
1. Cold Start
In order to be classified as a cold start the engine coolant temperature must be below 50ºC (122ºF) and within 6ºC (11ºF) 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 maximum 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.
If you have a 96 or newer vehicle (http://www.saturnfans.com/forums/showthread.php?t=122994&highlight=drive+cycle#) you have the OBD-II diagnostic system. This system is constantly monitoring the sensors and solenoids on the engine. If you have replaced the battery, disconnected the battery or cleared the codes after making a repair you will need to do what is called a "Driving Cycle". This will perform a diagnostic on all the systems the computer monitors. This cycle can be done in under fifteen minutes.
To perform an OBDII Driving cycle do the following:
1. Cold Start
In order to be classified as a cold start the engine coolant temperature must be below 50ºC (122ºF) and within 6ºC (11ºF) 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 maximum 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.
manicmech
12-29-2008, 05:23 PM
Thanks for the quick response. I'll try these things.
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