Drive Cycle
Hall Of Fame
Joined: Jul 2006
Posts: 12,204
Likes: 10
From: Gainesville, Ga.
lol, i think i've figured this out.
new member john w has a 2001 truck. he took it in for some kind of inspection required by his state, which we don't know, but it doesn't matter either. we'll assume its California Emissions testing. now, the inspector reports that he can't complete the testing, because the PCM reports that the battery has been recently disconnected, and it has not yet recorded enough data for it to possible set a CEL. So the inspector told the truck owner, john, that the emissions monitors were not ready, and that the computer was not in "ready" mode as defined by his equipment.
here's the answer.
Welcome to DF. About 100 miles.
LOL.
here's a better answer. about 1/2 way down this page.
http://www.aa1car.com/library/us796obd.htm
cut/paste for the lazy.
RUNNING AN OBDII DRIVE CYCLE
Suppose you have "fixed" an emissions problem on an OBDII-equipped vehicle. How can you check your work? By performing what is called an "OBDII drive cycle."
The purpose of the OBDII drive cycle is to run all of the onboard diagnostics. The drive cycle should be performed after you have erased any trouble codes from the PCM memory, or after the battery has been disconnected. Running through the drive cycle sets all the system monitors so that subsequent faults can be detected.
The OBDII drive cycle begins with a cold start (coolant temperature below 122 degrees F and the coolant and air temperature sensors within 11 degrees of one another).
NOTE: The ignition key must not be on prior to the cold start otherwise the heated oxygen sensor diagnostic may not run.
1. As soon as the engine starts, idle the engine in drive for two and a half minutes with the A/C and rear defrost on. OBDII checks oxygen sensor heater circuits, air pump and EVAP purge.
2. Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. OBDII checks for ignition misfire, fuel trim and canister purge.
3. Hold at a steady state speed of 55 mph for three minutes.
OBDII monitors EGR, air pump, O2 sensors and canister purge.
4. Decelerate (coast down) to 20 mph without braking or depressing the clutch. OBDII checks EGR and purge functions.
5. Accelerate back to 55 to 60 mph at half throttle. OBDII checks misfire, fuel trim and purge again.
6. Hold at a steady speed of 55 to 60 mph for five minutes.
OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions.
7. Decelerate (coast down) to a stop without braking. OBDII makes a final check of EGR and canister purge.
new member john w has a 2001 truck. he took it in for some kind of inspection required by his state, which we don't know, but it doesn't matter either. we'll assume its California Emissions testing. now, the inspector reports that he can't complete the testing, because the PCM reports that the battery has been recently disconnected, and it has not yet recorded enough data for it to possible set a CEL. So the inspector told the truck owner, john, that the emissions monitors were not ready, and that the computer was not in "ready" mode as defined by his equipment.
here's the answer.
Welcome to DF. About 100 miles.
LOL.
here's a better answer. about 1/2 way down this page.
http://www.aa1car.com/library/us796obd.htm
cut/paste for the lazy.
RUNNING AN OBDII DRIVE CYCLE
Suppose you have "fixed" an emissions problem on an OBDII-equipped vehicle. How can you check your work? By performing what is called an "OBDII drive cycle."
The purpose of the OBDII drive cycle is to run all of the onboard diagnostics. The drive cycle should be performed after you have erased any trouble codes from the PCM memory, or after the battery has been disconnected. Running through the drive cycle sets all the system monitors so that subsequent faults can be detected.
The OBDII drive cycle begins with a cold start (coolant temperature below 122 degrees F and the coolant and air temperature sensors within 11 degrees of one another).
NOTE: The ignition key must not be on prior to the cold start otherwise the heated oxygen sensor diagnostic may not run.
1. As soon as the engine starts, idle the engine in drive for two and a half minutes with the A/C and rear defrost on. OBDII checks oxygen sensor heater circuits, air pump and EVAP purge.
2. Turn the A/C and rear defrost off, and accelerate to 55 mph at half throttle. OBDII checks for ignition misfire, fuel trim and canister purge.
3. Hold at a steady state speed of 55 mph for three minutes.
OBDII monitors EGR, air pump, O2 sensors and canister purge.
4. Decelerate (coast down) to 20 mph without braking or depressing the clutch. OBDII checks EGR and purge functions.
5. Accelerate back to 55 to 60 mph at half throttle. OBDII checks misfire, fuel trim and purge again.
6. Hold at a steady speed of 55 to 60 mph for five minutes.
OBDII monitors catalytic converter efficiency, misfire, EGR, fuel trim, oxygen sensors and purge functions.
7. Decelerate (coast down) to a stop without braking. OBDII makes a final check of EGR and canister purge.
Last edited by dhvaughan; Jan 18, 2010 at 07:16 PM.
Banned
Joined: May 2006
Posts: 3,667
Likes: 1
From: Burnsville, mn - Pensacola, fl
gotcha, yea iv never lived in a state that i needed inspections for. Nore would i ever considering i have a hard enough time dealing with code inforcement here god help the fool who runs past my truck and hears it. or smells it for that case
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Grand Champion
Joined: Aug 2009
Posts: 5,971
Likes: 45
From: MAINE
i use to work in an inspection station, and what we always told customers when they had a CEL and failed emissions, is "go 200 miles to complete the cycles" (after problem was fixed obviously...sorry some people need everything spelled out...not saying you do)
always worked with that.
always worked with that.
Registered User
Joined: May 2011
Posts: 4
Likes: 0
Does this work for a caravan too? My husband is getting frustrated with our van.He put a EGR valve then disconnected the battery. 1st test rejected car "not ready" in 'O2',egr, & Cat. 2nd reject a week later EGR -ready ,but 'O2' & 'Catalytic' not.
