California Smog help question

[kensmith]

My son's 2000 Chevy Silverado 1500 5.3L OBD II did not pass on 2 issues, Evaporative System .....not ready, and Oxygen Sensor Heater .....not ready. Any ideas how to fix them so it will pass smog in California? Thanks

[So Cal Mark]

those are Readiness Monitors, they require a drive cycle to reset. Was the battery disconnected or replaced recently?
The evap test is normally run on a cold start up. The drive cycle usually includes a minimum 5 mile trip at a constant speed of 55-65 mph.
To pass the smog test, you only need more than half of the Readiness Monitors to be set, so if only two aren't ready it shouldn't be an issue

[kensmith]

those are Readiness Monitors, they require a drive cycle to reset. Was the battery disconnected or replaced recently?
The evap test is normally run on a cold start up. The drive cycle usually includes a minimum 5 mile trip at a constant speed of 55-65 mph.
To pass the smog test, you only need more than half of the Readiness Monitors to be set, so if only two aren't ready it shouldn't be an issue

Battery was changed and we drove it 40 miles at 65 mph. But only once since swapping out the bad battery for the new one. Maybe need to cycle it more? The smog guy said you have to pass all but one on the ready readings now but last year it was two that could be in the not ready.

[bobplyler]

It generally takes some in-town driving and highway driving to reset the indicators. If you want, an OBD-II reader isn't that expensive.

[So Cal Mark]

do a Google search for Drive Cycle on your vehicle. Every mfg has different drive cycle requirements for setting the Monitors. The hwy test is important that you don't exceed 65mph. That's tough to do in Calif without getting run over!

[kensmith]

I found the GM driving cycle. That's going to be tuff. A ton of things to do and may have to do 5 times day after day as the motor needs to cool down overnight. But it's a start!

[So Cal Mark]

some of those drive cycles are impossible without a dyno. but I'd try it a couple of times then have somebody connect a scanner and see if the monitors are ready.

[kensmith]

some of those drive cycles are impossible without a dyno. but I'd try it a couple of times then have somebody connect a scanner and see if the monitors are ready.

You are correct about the driving cycles. I found one for GM vehicles on the Internet and just in case anyone has an issue I will post it below. I know other makes have a very similar driving cycle to reset the ready monitors. We did exactly as the instructions read and it not only passed all the readiness monitors but also all the codes.




General Motors Driving Cycle
A complete driving cycle should perform diagnostics on all systems. A complete driving cycle can be done in under fifteen minutes.

To perform an OBDII Driving cycle do the following:

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.

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.

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.

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.

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.

Accelerate. Accelerate at 3/4 throttle until 88-96 km/hr (55-60mph). This will perform the same diagnostics as in step 3.

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.

Decelerate. This will perform the same diagnostics as in step 5. Again, don't press the clutch or brakes or shift gears.
Reprinted on OBDII web site courtesy of General Motors Corporation
© General Motors Corporation

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[baltobernie]

All >1990 cars registered in California must do this every time they disconnect their battery

[kensmith]

All >1990 cars registered in California must do this every time they disconnect their battery

Not sure about pre 1996 since they don't use OBD-2. They have I believe OBD-1 and there are different standards.

[So Cal Mark]

1996 and newer only have Readiness Monitors. Most OBD1 cars have a relearn procedure for idle speed, but that won't affect smog checks.