What was the code? 
Sometimes it takes as much as a few hundred miles...depending on the code.
Sometimes it takes as much as a few hundred miles...depending on the code.
P0420 is a common code. All it's telling is that the readings from the front O2 sensor didn't change with the rear O2 sensor. This could mean a vacuum leak, exhaust leak, bad O2 sensor, bad catalytic converter. In most cases, it can be a vacuum or exhaust leak. In our T-100s, most have found out that it's the O2 sensors. Make sure you git the right ones fer yer T-100. The cheapest O2 (Denso) can be found on the web. Search this forum fer some web links fer the places you can git the cheapest ones from.Thank you, gentlemen.
I think I found out how long it takes to reset the ECU....110 miles.....Unfortunately I figured this out because that's what the odometer read when the check engine light came back on.
Now. The part I am dreading.....I took it back and had the smog station guy read me the code and it is as follows:
P0420 Catlyst system efficiency below threshold (Bank 1)
Please tell me I'm not about to drop a grip of money on a catalytic converter????
RT
Dang...fergot about replying to this one.It's California, Bam. Thank you for the assist. I will make sure not to buy the Bosch! I'm glad you said it's usually the O2....much cheaper to deal with. I guess I'll start with the cheapest route and look for the leaks. Anyway to check whether an O2 is good or bad?
RT
Dang...fergot about replying to this one.
Best way to check the O2 sensor is when it's operating and with an ODBII reader. I like my Ultra-Gauge since it can read the O2 sensors in real time and you can basically see if it's responding correctly.
I got a P0420 code and doing some checking...I found some cracks in my air intake hose and some bad spark plugs (single ground electrode). After taking care of those and resetting my ECU...my P0420 code hasn't been back.![]()
Most mechanics see the P0420 code only as the converter being bad. Did you check the condition of yer spark plugs? Pull them and post some piccies of the business end. How's the condition of the air intake hose? Take it off and inspect the insides of it carefully fer cracks. You might even think about having yer injectors checked out/cleaned/conditioned as that was the next thing on my list. If you approach that there may be too much unburned fuel gitting to the converter...it would make sense that yer converter can't process all that raw fuel.Bam,
Did a little research on the UltraGauge. I will definitely be acquiring one of these little gems! Be puttin one in mamas 4runner, too.
Just to update my situation. I went ahead and just replaced the O2 sensors. Figured it couldn't hurt and wanted to see if this alone would fix the problem. Well, it didn't. I brought it to a local mechanic and he informed me the catalytic converter was bad. Can't buy an aftermarket one here in California for the T100, so Toyota quoted me $1500!!!! :yikes: The numbers it ran on the smog check were very close to passing, so he ran some stuff (forgot the name of it) through my gas tank. Took it back to get it smogged again and it passed this time!!!!! YEEHAW!!! I'm good to go for another couple of years. By then, I'll have enough saved up for the new converter. Anyway, its all good now. I appreciate all your input. You saved me a lot of wild goose chasing. :thumbsup:
On another topic, if I may. Do you know if the headliner in the SR5 is the same vinyl as my DX? I would love to upgrade to a velour one.
Thanks, again.
RT
Here's what my 1993 FSM sez...in the order to check.hey bam would my truck throw a code if an o2 sensor was bad cause im gettn like 13 to the gallon at best and it sucks but im not throwin any codes at all, and i know its obd1 but wouldn it tell me still?
Is there a California spec converter? Or is it some law in California that doesn't allow you to buy an aftermarket converter?I checked all over the place, but once they find out it's a T100 they say it's not possible to get one. If anyone out there knows of one for California please let me know. I'm on the look out now for a used one.