California Smog Problem, I/M=No.

See big update at post #16.



Hey Guys,
I have a problem. I'm in California and have to get my 2004 Tacoma, 4x2, base model smogged. This is my neighborhood run around and kid drop to school truck.

Since the Pandemic I'm driving it a lot less than in the past as I now work at home. About a year ago I had to replace an oxygen sensor, after which I cleared the codes and all was well.

Anyhow, in October I had to get it smogged for the registraction. It failed. Apparently the internal test protocal for the smog test was "not ready". The smog guy and google told me just to drive it more, about seventy miles and it will be ready. I've not driven it over three hundred miles and the scan tool still reads "I/M Ready= No".

I'm now driving it everyday on and expired registration and I can't get it to status "ready". What can I do?

Mauserguy

 

It can be a PITA to get the monitors to complete.
Here is a good site that might help.
It would help if you knew what ones haven’t completed.

https://antiochstarsmogcheck.com/toyota-drive-cycle-obdii-readiness-monitors/

 

Which monitors is not ready?

In CA, 4 of the 5 monitors must be ready. Only exception is the evap.

 

Yeah, I smogged my truck in 2021 with the evap monitor not ready.

When I got to the smog shop I let the tech know the evap monitor was not ready and asked it it would be a problem. It wasn’t.

See if you find out which monitor is indicating not ready. If it’s evap you should be good to go.

 

Did you replace the sensor with an aftermarket sensor or with a Denso sensor? It matters and can be the reason why you're having issues. A year is more than enough time for that sensor to clear. It's either the sensor you put in or something else has failed which caused the readiness monitors to go not ready.

Check for fault codes. Going to need to know what code has popped up that has pissed off your readiness monitors.

 

Does your reader show any pending codes?

I'd disconnect the battery, give it 10 minutes, and hook 'er back up. That'll reset the ECU. That does mean you'll have to drive it long enough for the monitors to run again, but that should really be around 60 miles between some stop and go surface streets and some extended hops on a freeway or highway.

You likely have another underlying issue preventing the monitors from completing, but they might not be frequent or out of spec enough to throw a CEL.

I assume you've paid your registration even though you haven't passed smog? I mean, you could still get pulled over, but if you have the receipt or statement showing it's paid, and you clearly explain what you've done to resolve the issue and pass smog, you'll be fine.

 

Thanks guys. I checked the records and it was not a Denso part. It was aftermarket. I've driven it up and down the freeway a couple of times with no luck. I'm afraid to unplug the battery as that may make another sensor turn off. I did pay the registration fee, I just can't get this stupid thing to go on. I'll try to get a genuine Denso part and plug that in.
Mauserguy

 

My old bmw m3 had this problem with a secondary air pump, no codes but it refused to become ready. Replaced it and it was ready next day.
did you use an oem sensor?

 

No, it was aftermarket. I just ordered a Denso. I called my local dealership, but they weren't answering the phone. Something is going on there. They have almost no cars on their lot. I don't know if that's a supply chain problem of if they are going under.
Mauserguy

 

Don't stress over it. The Denso part is the go to part around here anyway.

I would suggest resetting the ECU when you change the sensor though. I don't think you're doing yourself any favors by trying to hold the other monitors.

 

Every time you unplug your battery, you are resetting the monitors and starting it all over...I would avoid doing that if you can.


I had this issue last time, I couldn't get my cat monitors to set to 'ready' for the life of me...drove 2k miles and still wouldn't set. Finally dumped a can of Cataclean in the tank, put it in 4lo on some dirt and in ~5 miles the monitors turned green...I was ecstatic because I had like 2 days before I was going to be overdue on registration lol.

I would try the Cataclean stuff, its possible if it's the cat monitors that aren't setting that your cats are on their way out. Not enough to trip a code but enough that it isn't satisfying the monitors. The Cataclean will give them a bit more life, enough to pass smog hopefully.

 

If you have access to an OBDII scanner, check it. Just to be sure nothing else is amiss, I would.

Hopefully once the OEM/DENSO sensor is in, you'll be good to go.

 

I got my Denso sensors from our local Pep Boys, I wouldn't count on them to know which one you need so make sure to have the part number handy. But then at least you know you're getting a legit sensor, there are a lot of knockoffs floating around online. If it's cheap it's probably cheap for a reason just beware

 

Hi guys,
I want to thank you all for your input. So, here's an update.

I've been really busy with work, and this last weekend my wife wanted to drive seven hours to Monterey for fish dinner. That took all weekend (the kids liked some of the sights, though; my daughter loved the elephant seals, burping and farting fish smells). Anyhow, the night before the trip I got the oxygen sensor replaced with a Denso unit. It cost $200.00.

After the return from the trip I drove the truck around as much as I could. I took today off of work and drove it all around for two hours. Frankly, I think that the truck was running better, smoother, accelerating with more authority. The monitors, though, refused to turn on. Finally, the check engine light came on- PO136.

I got a second, downstream oxygen sensor now, and I'll likely replace it tonight. I'm too frustrated to do it now. I have to go walk the dog.
Mauserguy

 

Feel your pain and frustration, sucks.

Try this and see if it clears the code -

A. Allow the engine to idle for two minutes.
B. Warm up the engine until the Engine Coolant Temperature (ECT) reaches 167F (75C).
C. Drive the vehicle over 30 mph (48 km/h) for more than 40 seconds.
D. Stop the vehicle and allow the engine to idle for more than 20 seconds.
E. Repeat steps C and D at least 8 times in one driving cycle. (Do not cycle the ignition key.)

In addition, perform the following steps for the Rear O2S Readiness Monitor:
A. Select second gear.
B. Allow the vehicle to run at 30 mph (48 km/h) or more.
C. Keep the accelerator pedal “off–idle” for more than 10 seconds.
D. Immediately after step C, release the accelerator pedal for at least 10 seconds without depressing the brake pedal (to execute the fuel–cut).
E. Decelerate the vehicle until the vehicle speed reaches less than 6 mph (10 km/h).
F. Repeat steps B – E at least twice in one driving cycle. (Do not cycle the ignition key.)

For reference -

 

Big Update!

Okay, so this last weekend I replaced the rear oxygen sensor with a new Denso unit. I stired up a nest of brown widows back there. Anyway, I reset the check engine light then drove it. I drove it as closely to Area 51's protocol as I could this morning after dropping my daughter off at school. I plugged in the scanner and it came up IM Ready = Yes! Yayyyyy....

I just got back from the smog station, and it passed.

Thank you guys for your support and suggestions. Looking back, I can see that the oxygen sensors were getting old and week, and the aftermarket sensor I previously used was innadiquate. It was both sensors that were my problem, even though they weren't throwing codes.

Thanks guys.

Cheers,
Mauserguy