[rt968]

Just tried to get my 97 3.4L smogged....California style....(honey we're moving to Texas!...but that's another story)
The guy had to clear a check engine light that came on two days ago. Figured I'd "kill two birds with one stone".
He sets up the machine and says
"your computer needs to reset"
me--"I thought you just did that?
"you have to drive your car continuously until the computer clears"
me--"How many miles"
"I don't know"
me--"HUH?"

So I drove for seventy miles on a little day trip with the family.....still not "ready".

Somebody please tell me I'm not a very large tool and just fell for an not very funny practical joke.

RT

 

[BamZipPow]

What was the code?

Sometimes it takes as much as a few hundred miles...depending on the code.

 

[rt968]

Yikes!! A few hundred!?!? The smog station guy says it needs to be "continuous".....I take that as all in one pass....no shutting the engine off....drive it till either the check engine light comes back on, or it finally resets. Is this the case??? Please, Bam....tell me something good
RT

 

[rt968]

I completely forgot to find out what the code was....it was just supposed to be a quick smog to get this thing registered. He threw out the word catalytic converter. I'm hoping just a post O2 sensor.

 

[fourwd1]

You can clear all codes by disconnecting the battery for 15 min or so, but then it may take several small trips for the ECM to "relearn" the vehicle and regain optimal operation (providing any existing problems have been fixed).

 

[rt968]

Ok, fourdw1. You're making me feel better. I thought I was going to have to drive to Vegas for a minute there just to smog my T.....wait a minute....that doesn't sound so bad after all! Haha. Thanks for the response.
RT

 

[fourwd1]

No problem.

 

[Zuke76]

Bam or fourwd correct me if I am wrong but I believe you can just pull the EFI fuse for 15 min. The EFI fuse is in the fuse box in the engine bay on the drivers side. This way you don't lose all of your preset radio stations.

 

[BamZipPow]

It's the other part...where the computer has to relearn some parts...like the fuel trims.

 

[Boomer1961]

ECU goes to default mode on reset

Then it runs rich and forwards the timing to ~7-10 degrees.

In the factory service manual they talk about one trip or two trip resets.

Near as I can tell the longest reset is two trips reset like for the coolant temperature (i.e. must get up to then run a while at temperature).

In addition after this since you probably have an old sluggish catalytic converter it will be saturated from running rich (ECU IN DEFAULT MODE) so thats where some folks talk about the 200 mile thingy. I think though it would be safe with a good half an hour of freeway driving after you complete your two trip reset.

Most folks are not aware of this and after making a repair run off to the smog test only station then get an automatic failure as ECU has not been reset or the catalytic converter is putting out to much HC and they then run off an buy a new catalytic converter.

The two hundred mile thingy is the way safe default answer, but even then you better be sure to do at least two trip reset (drive until its hot, turn off and let it cool, then drive it till its hot again).

 

[rt968]

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

 

[BamZipPow]

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

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.

****DO NOT GIT THE BOSCH O2 sensors!!****

Is yer T-100 a California or Federal spec vehicle?

 

[rt968]

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

 

[BamZipPow]

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.

 

[rt968]

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.

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

 

[jont100]

1500!!???!! man well have you checked online some places have 50 state legal converters and 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?

 

[rt968]

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.

 

[BamZipPow]

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

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.

The headliner of my 1998 T-100 SR5 is vinyl...so I'm think it's the same as the DX.

 

[BamZipPow]

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?

Here's what my 1993 FSM sez...in the order to check.

Poor Fuel Economy:

Fuel leakage
Fuel quality
Accelerator pedal link
Dash pot
Clutch
Brake drag
EGR system
Fuel cut system
Spark plug
Distributor
Compression
Cylinder head
Compression
Injectors
Cold start system
Engine coolant temp sensor circuit
Throttle position sensor circuit
Volume air flow meter circuit
PNP signal circuit
AC signal circuit
Heated oxygen sensor circuit
Intake air temp sensor circuit

If yer O2 (heated oxygen sensor) sensor was bad, it might pop a code.

Are there any other issues going on? Last time you did a tuneup? Is the truck properly aligned? What kind of tires you got on there?

 

[BamZipPow]

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.

Is there a California spec converter? Or is it some law in California that doesn't allow you to buy an aftermarket converter?