# BMW Drive Cycle to Ready O2 and Catalyst



## Martin2017 (Aug 12, 2017)

Hi all,

Drive Cycle nightmares and misinformation.

I have a low mileage X3 that has never had any problems passing emissions. I made the huge (I didn't know what I didn't know) mistake of taking the car to the dealer thinking an oil change was a good idea before the test. $2K later for various fixes, I can't get through the drive cycle and am living in a drive-everywhere like a crazy person nightmare watching the clock run out and thinking I will end up with a car that cannot be driven. 

The Service Engine Soon (SES) light had come on intermittently for a few years. The dealer said they couldn't fix it unless I brought it in while the light was on. I finally bought an OBDII scanner, found the code and then took it into the dealer while the light was off. They fixed it, they put in a new battery and did some other things. Big bill. Big nightmare.

It flunked the emissions test which was a huge surprise. I found out what a drive cycle was and then called the dealer to ask what to do. They said 200 miles of regular driving was sufficient. It wasn't. 2nd flunk. 

It took me awhile to realize that the OBDII scanner I already owned would show the same thing the emissions test would so I have been driving and plugging it in and it still shows this:

O2 Sensor Unready (O2 Heater is Ready) 
Catalyst Unready

Having called BMW genius (not) and customer service as well as the dealer the upshot is that no one has a clue. Not a clue. The drive cycle is any or none of the following:

200 miles regular driving
500 miles regular driving
700 miles regular driving
long highway miles are necessary
long highway miles are useless 
40 engine starts are required
Drive 55 mph for 3 minutes, coast down to 20 mph, drive again at 55 mph for 5 minutes, coast to a stop and idle. None of this is possible or legal anywhere I have seen.

I see the drive cycle on this site which, I think, is meant to be done in sections since doing it altogether is not possible for most people. In order to fix my problem, I see:
drive 20-30 mph steadily for 4 minutes
drive 55-60 mph steadily for 15 minutes
Test will not work if above 3K RPMs and 60 MPH
I have already done this. This is also not working. 

I now have put almost 500 miles on my car in a short period of time (time running out) and the drive cycle is still some elusive, inexplicable and unreachable ghost. This is RIDICULOUS. I have no idea if driving another 1000 miles will fix it since the dealer was 100% sure that 200 miles was 100% ok. 

What I am currently looking into is the idea that a weak, defective battery - even if starts are never an issue - could cause both the O2 Sensor (O2 Heater is Ready) and Catalyst to show UnReady. I have a brand new $300 battery...from the dealer. 

This is a nightmare and I am amazed that no one at BMW HQ customer service or genius (not) has a clue what any of this is. Considering that emissions testing is very common, I cannot imagine why this is the case.


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## Martin2017 (Aug 12, 2017)

*BMW Drive Cycle for Emissions Testing Unready to Ready*

I appreciate the people who write up their solutions so here's mine on the Drive Cycle for emissions testing that worked for me.

I have a bluetooth OBDII reader and an free app for my phone called Torque. They are easy to connect up and I get the same readings they have at the testing facility.

This is what I think finally caused the last two READY indicators to come on:

O2 Sensor
Catalyst

I found a deserted stretch of industrial road late at night that had a few miles of well-timed traffic lights. The speed limit was IIRC 35+ but I went through this stretch of road, hitting all green lights, under 30. I did this several times and FINALLY the two sensors went from UNREADY to READY.

I don't know if this was just a coincidence or I really did need a few uninterrupted miles of low-speed, steady driving. It's inane.

I hope this helps someone who is tearing their hair out over this. It sure beats the dangerous nonsense that is posted on line about coasting at low speed on highways. Don't do that! That's just nuts.

Alternatively, don't have your battery pulled within, say, 6 months of running a test.


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