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Hey everyone, so recently I took my GS in to get smog’d and failed due to my IM monitors not being ready. In my state, you can have one monitor not ready or incomplete and still pass, in my case I had 2 incomplete; oxygen sensor and catalyst monitor. I came home and researched this topic up and down various forums and followed the drive cycle from a 2002 Lexus TSB. I even went as far as replacing B2S2 as I had previously done some work under the car and removed and dropped the sensor, someone mentioned that doing that could cause slight issues, plus the sensor was old so I figured why not. Anyway, both my OBD-II scanner as well as techstream show no pending or stored codes and obviously I have no CEL. After replacing my O2 sensor, I cleared the DTC’s and performed the drivecycles. Got everything to show ready except oxygen sensor and catalyst monitor. From what I’ve read, the oxygen sensor must show ready for the catalyst monitor to run however in techstream my catalyst monitor shows pass, yet incomplete whereas the o2 sensor portion shows a question mark. Sorry for the long winded post, just hoping someone else who has been through this can provide some advice. Thanks in advance!
If I recall, it takes a day (or two) of driving before the cycles complete.
Hope it helps
Appreciate the reply. Unfortunately, I’ve been driving the car for about 2 weeks, I have put roughly 300 miles on it since resetting the DTC’s. I’ve also been sure to get a mix of stop and go and long periods of cruising at freeway speeds to no avail.
I don’t have time to look it up right right now but google drive cycle for your gs. I used that info and my Bluetooth OBD2 reader with the app OBD Fusion
Hey guys! Really appreciate the feedback. It’s possible that the cats in the manifold are going bad with age, although when I had the midpipe off I didn’t see any of the honeycomb material or anything and the car seems to run fine. Either way, I’ve attached pictures of the drive cycles out of the TSB that I’ve mentioned. If these are not the right drive cycles I should be using, feel free to let me know. A friend of mine recently went standalone and has all his factory O2 sensors, so I’ll throw those in within the next couple days and redo the drive cycles to see if I can’t get the monitors to show ready. Thanks again CL fam. Catalyst Monitor Drive Pattern Oxygen Sensor Drive Pattern
Do you have a GS3 or GS4 and what year is it? I have to do this every year to pass NYS inspection cause I have an aftermarket valve body in my transmission and it throws a code for shift solenoid. Anyways, I got it down to a 15min drive in my 98 GS4 and all monitors except cat are ready to go. I'll try to find the excact sequence I used and post it. It used to take an hour or two to get monitors ready. The one thing I remember that made a huge difference was, start the car when it's cold and let it idle for 13min before doing anything. After it idled for 13min I would drive 1/2 mile turn the car off, open the gas cap, put it back on and a bunch of monitors would be ready including o2 monitor. Then drive for 7min between 35&45mph never giving more than 30% throttle and not hitting the brakes. After the 7min, pull over let the car idle for 10 minutes (maybe less, I don't remember) turn car off for a few minutes, then do 45&55 for 8 minutes and you should be good. My memory sucks so I'll try to find the instructions I followed. Hopefully this long a** rant helps lol.
Do you have a GS3 or GS4 and what year is it? I have to do this every year to pass NYS inspection cause I have an aftermarket valve body in my transmission and it throws a code for shift solenoid. Anyways, I got it down to a 15min drive in my 98 GS4 and all monitors except cat are ready to go. I'll try to find the excact sequence I used and post it. It used to take an hour or two to get monitors ready. The one thing I remember that made a huge difference was, start the car when it's cold and let it idle for 13min before doing anything. After it idled for 13min I would drive 1/2 mile turn the car off, open the gas cap, put it back on and a bunch of monitors would be ready including o2 monitor. Then drive for 7min between 35&45mph never giving more than 30% throttle and not hitting the brakes. After the 7min, pull over let the car idle for 10 minutes (maybe less, I don't remember) turn car off for a few minutes, then do 45&55 for 8 minutes and you should be good. My memory sucks so I'll try to find the instructions I followed. Hopefully this long a** rant helps lol.
Sorry, my fault for not including that in my original post but I have an 01 GS3. If you can find the cycle you used I’ll definitely give it a shot! I appreciate the long rant as I’m going crazy feeling like I’m running out of options. Thanks again!
Sorry, my fault for not including that in my original post but I have an 01 GS3. If you can find the cycle you used I’ll definitely give it a shot! I appreciate the long rant as I’m going crazy feeling like I’m running out of options. Thanks again!
So I have the same TSB that you listed. Try doing it the way I said and make sure you have 1/2-3/4 tank of gas before you start. Good luck
I tried doing it the way you described, including the 13 minutes at idle after being cold soaked to no avail. I replaced all my o2 sensors and tried again, nothing. Today I went as far as driving the car on jackstands per the TSB exactly and I cannot get my o2 and catalyst monitor to show ready. So far I’ve put roughly 500 miles on the car with multiple drive cycles performed, normal stop and go, freeway, etc. Any other options/ideas would be appreciated.
I run into customer cars that just wont pass o2 and cat monitors, but also wont throw codes. It's usually lazy o2 sensors. If the cat is bad, it will set a code. The EPA has made damn sure of that. I'm thinking your o2s are good enough to not throw a code, but not good enough to clear monitors. To know which one(s) you'd have to watch the voltage wave form and understand what a good pattern it. Or else just replace all o2s and call it good. It should clear monitors after that.
I run into customer cars that just wont pass o2 and cat monitors, but also wont throw codes. It's usually lazy o2 sensors. If the cat is bad, it will set a code. The EPA has made damn sure of that. I'm thinking your o2s are good enough to not throw a code, but not good enough to clear monitors. To know which one(s) you'd have to watch the voltage wave form and understand what a good pattern it. Or else just replace all o2s and call it good. It should clear monitors after that.
Thanks for the reply. I actually did replace all 4 o2 sensors. So far I did one complete drive cycle, since replacing them, as per the TSB to the T(used jackstands) to no avail. I’m going to continue to drive the car over the next few days and hope that changing the sensors helped. Will let you guys know. Thanks again for all the help/advice!
If your car is over 20 years old you do not have to pay full price for inspection. I live in Texas and my inspection is only $14.00. If you do not tell the inspection place that your car is a classic and it is only 14 dollars they won't mention it either 9 times out of 10.
05-03-19, 10:06 PM
Readiness Monitors?
