2003 Tacoma cat monitor won't set.

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2003 Tacoma cat monitor won't set.

none
I have my Tacoma from HELL back. http://stop-the-star-program.3084.x6.nabble.com/2000-Toyota-Camry-Catalyst-Monitor-td5068511.html

It is a 2003 3.4L V6 and will not run the cat monitor. I searched ALLDATA for the enable criteria but all I really find is the Toyota TSB on how to run the cat monitor on an A/F sensor equipped vehicle which I've tried to do again to the letter and direct hit is all over the place but I got a few ideas.

It has had both cats replaced and the thermostat. I know the front cat was just done before I saw it last time and has no leaks so I took the rear cat and O2 off my Tacoma and tried it. The rear O2 would get as high as 0.840V but the best I could hold steady in 5th gear at 50mph was 0.740v which seemed good.

The coolant temp was at 180 when I started both times (stock t-stat rating) and would go as high as 185 deg but would drop as low as 176. On Identifix someone said the coolant temp has to be at 185. I'm wondering if replacing the thermostat again with a 192deg might help?

The A/F sensor has been replaced before all this and it is not a Denso unit. Looking at pictures I'm thinking it is a NTK sensor and I don't know if they are good or cheap. Since my Tacoma is an automatic transmission I can't swap sensors because the lead is much shorter on mine. I really don't know much about checking them other than looking on the scan tool to make sure it is cycling.

Any pointers or recommendations would be greatly appreciated.
People are usually shocked when they find out I'm not a very good electrician.
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Re: 2003 Tacoma cat monitor won't set.

scanner
none wrote
Any pointers or recommendations would be greatly appreciated.
How about you give Jamey T a call and compare notes.  Ask him if he's ever gotten his problem Toyota truck to run the cat monitor.  
Why make it simple, when it will work equally as well complicated.
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Re: 2003 Tacoma cat monitor won't set.

Best Answer I Can Give
 JT if it is who I think it is, is in the same town as me. SHARP guy. His friend Dylan made have some answers.
My youngest son was having the same sort of problem on his TC. He one night @10 just got on the 101 and set the cruise at 57mph and drove it for 16 minutes. It finally set. He did it late at night so, NO TRAFFIC. The TC is a 06. He is one smart kid.

 Not sure of the monitor, but did what it said to do on the Net. Pretty sure it was the one you are chasing.
 Never make fun of the choices your wife makes. You were one of them.
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Re: 2003 Tacoma cat monitor won't set.

none
In reply to this post by scanner
I have no idea who JAMEY is. Are you talking about THORNTON? I searched his iATN posts but didn't find anything pertaining to this. I will try messaging him. I hate to call people during busy work hours.

Thanks, TOM
People are usually shocked when they find out I'm not a very good electrician.
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Re: 2003 Tacoma cat monitor won't set.

Juicebox
In reply to this post by none
I've failed about 100 A/F equipped toyotas 00-04? for incomplete cat monitor - monitor description says run 35-45 for 16 minutes!!!! I have to emphasize this to all my customers when they fail, because its extremely hard to find a road to do it on. I assure you that it works though.
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Re: 2003 Tacoma cat monitor won't set.

none
I tried this again yesterday while fallowing trucks up I80. They are going at this speed for long periods going up the grades but not long enough before they get more speed on a flat. Then the Toyota TSB says "If readiness status does not switch to "complete," ensure preconditions are met, turn the ignition OFF, then repeat steps "a" and "b." "

I'm concerned about running my dyno for this long continuously but I might try that. My Tacoma (A/F equipped) will complete cat monitor without running that long so I thought I could get it to complete on the road.

I wonder if changing the thermostat to a 192 deg might help. Some people on Direct hit said it had to be at 185 deg but this thing drops below that to 177 often (which is still within the range on the TSB). I don't know if they were actually watching on a scan tool though.  
People are usually shocked when they find out I'm not a very good electrician.
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Re: 2003 Tacoma cat monitor won't set.

Best Answer I Can Give
 I have about 5 guys in this town that when NO one can get it Jamie is one of them you send it to. He is a nice guy. He is the ONLY one in town with Brake and Lamp. He Cares and will spend the COST to fix it right.
 Never make fun of the choices your wife makes. You were one of them.
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Re: 2003 Tacoma cat monitor won't set.

scanner
In reply to this post by none
none wrote
I have no idea who JAMEY is. Are you talking about THORNTON? I searched his iATN posts but didn't find anything pertaining to this. I will try messaging him. I hate to call people during busy work hours.

Thanks, TOM
Yes, and he's located near Besta.   I spoke with him at length on the phone about a Transit that I couldn't get the EGR monitor to run.  I'm pretty sure we spoke of a Toyota Truck he couldn't get the CAT to run.  Now that I think of it, it might have been the O2 sensor that hadn't run.   He had a lot of insights regarding how Toyota runs their monitors.  

I usually won't try running a monitor on my dyno for more than 15 minutes.  I've gone longer though.  The vehicle may need a key reset, but that's hard to tell on a pre-CAN vehicle.  Pre-CAN vehicles are difficult to determine what is preventing the monitor to run.

At least, on CAN vehicles, you can see if a monitor is enabled or not.  In Mode 6, populated parameters are set to zero when you clear the memory.  In Mode 9 you can see In-Use Performance Tracking.

Changing the thermostat sounds like a good idea, it's inexpensive, and it better than doing the same thing over again.  

 
Why make it simple, when it will work equally as well complicated.
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Re: 2003 Tacoma cat monitor won't set.

Samy
In reply to this post by none
I think When the ECU sees the engine has reached its NORMAL operating temperature it starts to monitor the cat even though if temp drops down to 180' on the same key cycle.
I did this trick with a RAV4 2000 that had been all over the place (new parts) and of course no body fixed it.
I warmed it up good, Got on freeway and less than 7 Miles it ran the cat monitor. Next thing I replaced the thermostat with OEM then I reset it and went for the same ride. This time it ran the monitor for the second time around same area may be a mile after the 1st run.
I maybe wrong but it worked for me.
Good luck and please keep us posted what was the fix.
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Re: 2003 Tacoma cat monitor won't set.

none
In reply to this post by scanner
I did check the MODE 6 and it had five tests listed. I didn't know which one each one was but they all showed pass so I assumed none were for the CAT.

What RPM range do you think I should I shooting for? The TSB doesn't say anything about what RPM range but I don't know if I should be in 4th or 5th gear. 5th is really lugging the motor 35-45mph but it keeps the rear O2 sensor voltage high. I hate to shift since it says to keep the throttle as steady as possible.
People are usually shocked when they find out I'm not a very good electrician.
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Re: 2003 Tacoma cat monitor won't set.

none
In reply to this post by Samy
I am going to plug in and watch coolant temp on my own Tacoma tonight and see where it runs.

I will post the fix if I EVER get it to run the test.
People are usually shocked when they find out I'm not a very good electrician.
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Re: 2003 Tacoma cat monitor won't set.

scanner
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none wrote
I did check the MODE 6 and it had five tests listed. I didn't know which one each one was but they all showed pass so I assumed none were for the CAT.
That's one thing about pre-CAN Mode 6, you don't know if the monitor completed or not.  If you clear the codes, you might still see a value and a pass.   Try it with Techstream, you might see all passes in Mode 6, even after clearing memory.   If you see the same value for the CAT after clearing, you know the monitor never ran.   You would access that when looking at the monitor status window.  

CAN vehicles are great.  All manufactures have to follow CARB standards, and all test numbers are required to have the same definitions.  They are all required to have misfire counters too.  When you clear memory, all the values go to zero.   All in generic OBDII.  

What RPM range do you think I should I shooting for? The TSB doesn't say anything about what RPM range but I don't know if I should be in 4th or 5th gear. 5th is really lugging the motor 35-45mph but it keeps the rear O2 sensor voltage high. I hate to shift since it says to keep the throttle as steady as possible.
I'm not sure about the RPM range, but I don't think the engine should be lugging.   Maybe try with 5hp load on the dyno.  Try it with the overdrive OFF.   Maybe start off in 4th gear position if it's there.   Jab and feather the throttle to try to keep the sensors high and then try and hold steady.  
Why make it simple, when it will work equally as well complicated.
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Re: 2003 Tacoma cat monitor won't set.

none
scanner wrote
...That's one thing about pre-CAN Mode 6, you don't know if the monitor completed or not.  If you clear the codes, you might still see a value and a pass....
OH. I didn't know that.
People are usually shocked when they find out I'm not a very good electrician.
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Re: 2003 Tacoma cat monitor won't set.

Best Answer I Can Give
 Being the DUMMY I am, PLUS what I understand, The reason we don't need Evap is because of Toyota.
Evap on a Toyota needs to be under 78 Degrees before it will start. Some places in the US will never see under 78 in the summer time. Thus the Evap will not set. THAT IS WHAT I WAS TOLD.

 Now you have put down a couple times about heat being a factor. Maybe you are on to something with the higher Thermostat.

 Does Toyota rely a lot on heat being high enough? Hey I'm just a dummy.
 Never make fun of the choices your wife makes. You were one of them.
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Re: 2003 Tacoma cat monitor won't set.

none
In reply to this post by none
I checked my own Tacoma's coolant temp with my scan tool and it ran 195-200 on the same drive so He's going to change the T-stat to a 195deg and try the drive cycle again.
People are usually shocked when they find out I'm not a very good electrician.