i have been fighting the dreaded drive cycle to get my emissions done in tn. i have failed 3 times due to the computer not being able to read the emission moniters. i have driven over 1000 miles in traffic conditions highwayconditions and at the dragstrip. outside temps from 93* to 65*. i still cant get the catalyst,o2 sensor and heated o2 sensor to read.
i have searched drive cycle on the web and done the driving req.
any ideas?

 

I suspect that you've tried this already, from Understanding OBDII: Past, Present & Future
If not:

The purpose of the OBDII drive cycle is to run all of the onboard diagnostics. The drive cycle shold 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.

 

yes thats the exact drive cycle i have done. then a 800 mile round trip to bmaorgans town for a full day of drag racing! so i should be ok. but alas i still fail the test as it cant read the monitors. its driving me bonkers!

 

I can't imagine what more you could do. There must be more to it. Do you have access to a scanner that can tell what specifically is being flagged?

 

my op listed whats not being read. im just going to have to drive it some more i guess. i have the dashdaq now so i wont have to disconnect the battery anymore to clear codes but any electrical work requires a disconnect. guess no more modding until i pass this stuff!

 

Make sure the wire for the computer memory is constant on. Fuse could be burnt.It could be resetting every time you turn off the key. Happens on a lot of cars.
When you work on the car you should use one of those 9 volt battery adapters plugged into the cig. lighter, just dont open the doors as that will kill it quick.

 

not sure which computer your talking about. if its the dashdaq you mean rcompart helped me set it up and its fine. he does a fantastic job of walking a non electrical guy thru the process and i have zero issues with it. i actually have been battling this issue since feb when i started to get emissions done. before my dashdaq install, had to disconnect the battery to solder all the connections. the main reason is i dont like to put a ton of miles on my car and would have thought my 1000 mile trip would have reset it.

 

Was talking about the vehicle's OBD computer.