OBD - Pollution Inspection

[bowtie123]

Hi All,

2005 Deville DTS

I went thru pollution inspection today and did not make it.

While it did not fail, they said the OBD was "Not Ready"

It would not give enough information.

They said it could be from the battery being disconnected (No)

or from codes being cleared recently.

I do check and clear the codes on a regular basic and I checked them

while I was driving to the inspection station. There weren't any so I did

not answer "Yes" to the "Clear All Codes".

They said to drive it for a couple of weeks and come back.

Anyone had this happen to them.

[JimD]

There is a 'drive cycle' that will set the readiness flags in your OBD. They gave you good advice when they told you to simply drive the car for a while.

Or you can do the routine described below.

********************************************************************************

General Motors (specific) OBD II Drive Cycle

Performing a GM OBDII Driving cycle:

1. Cold Start. In order to be classified as a cold start the engine coolant

temperature must be below 122°F (50°C) and within 11°F (6°C) of the ambient

air temperature at startup.

Do not leave the key in 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 55mph (88km/hr) 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 55mph (88km/hr) 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 20 mph (32km/hr). During this time the EGR, Purge and Fuel Trim

diagnostics will be performed.

6. Accelerate. Accelerate at 3/4 throttle until 55-60mph (88-96 km/hr). This

will perform the same diagnostics as in step 3.

7. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) 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.

Further useful information:

Understanding On-Board Diagnostics (from the Illinois EPA):

http://www.epa.state.il.us/air/vim/guide/u...anding-obd.html

from "A Guide to the Illinois Vehicle Emissions Inspection Program" (March

2005 revision)

[ http://www.epa.state.il.us/air/vim/guide/ ]

[bowtie123]

Thanks Jim,

This is great information.

I will only have to make the 50 mile

round trip to the inspection station station

one more time.

Thanks again,

There is a 'drive cycle' that will set the readiness flags in your OBD. They gave you good advice when they told you to simply drive the car for a while.

Or you can do the routine described below.

********************************************************************************

General Motors (specific) OBD II Drive Cycle

Performing a GM OBDII Driving cycle:

1. Cold Start. In order to be classified as a cold start the engine coolant

temperature must be below 122°F (50°C) and within 11°F (6°C) of the ambient

air temperature at startup.

Do not leave the key in 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 55mph (88km/hr) 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 55mph (88km/hr) 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 20 mph (32km/hr). During this time the EGR, Purge and Fuel Trim

diagnostics will be performed.

6. Accelerate. Accelerate at 3/4 throttle until 55-60mph (88-96 km/hr). This

will perform the same diagnostics as in step 3.

7. Hold Steady Speed. Hold a steady speed of 55mph (88km/hr) 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.

Further useful information:

Understanding On-Board Diagnostics (from the Illinois EPA):

http://www.epa.state.il.us/air/vim/guide/u...anding-obd.html

from "A Guide to the Illinois Vehicle Emissions Inspection Program" (March

2005 revision)

[ http://www.epa.state.il.us/air/vim/guide/ ]

[BodybyFisher]

See this thread also, see Scotty's posts, I posted a drive cycle chart

http://caddyinfo.ipbhost.com/index.php?sho...;hl=drive+cycle