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roy, import/domestic specialest
Category: Toyota
Satisfied Customers: 6197
Experience:  ASE master tech for 40 years
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I'm ***** *****. I have a 2004 Toyota Tacoma that won't pass

Customer Question

Customer: Hi I'm ***** *****. I have a 2004 Toyota Tacoma that won't pass emissions. I have a scanner and it there are no DTC's present but it gives me binding CAT and EVAP signals. I was told by the Smog station that my Catalytic converter was bad so I replaced the converter and both upstream and downstream Ox sensors. What do you think the isse could be?
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Submitted: 1 year ago.
Category: Toyota
Customer: replied 1 year ago.
I meant Blinking CAT and EVAP I/M monitor status and yellow for emissions status.
Customer: replied 1 year ago.
Just some extra info: 2004 Toyota Tacoma Crew Cab SR5, 4x4, V6 3.4 Liter 5Vz-FE engine.
Expert:  roy replied 1 year ago.

good evening my name is ***** ***** I will assist

I assume you mean the monitors were not set and thats why it failed??? was there any recent work performed that you re set or cleared the codes???

has a drive cycle been performed to verify the repairs???


Customer: replied 1 year ago.
Hello Roy, I'm not sure what you mean by monitors being set. Here's what happened. I brought the truck in to be smogged a few weeks ago. The smog tech told me that it failed and the Catalytic converter was bad. I then check the status of the engine with my personal automotive scans tool. The scanner tested the truck and came up with no DCT error codes but had blinking CAT and EVAP monitor signal. I believe this means it cannot complete the test and there may be an issue present. So I replace the catalytic converter as well as both forward and aft O2 OBD2 sensors. I then tested the truck again and got the same result on my scanner. Can you help me figure out why it won't pass the test on my scanner and pass emissions?
Customer: replied 1 year ago.
Also unjust read that a drive test can take up to a week. Is it possible that the drive test is still ongoing? I have been driving the truck for about three days since I changed out the cat converter. Is that long enough?
Expert:  roy replied 1 year ago.

a drive cycle can be done in a hour or so of driving. I do it all the time and it works as long as there are no other failures.

who told you it takes a week???


Customer: replied 1 year ago.
I read it in the scanner manual.
Customer: replied 1 year ago.
I'm not a toyota mechanic but a electronics tech but In my experience if working on car for 25 years the test usually happens in 15 -20 mins. That's why I'm puzzled but this. What else could be causing the test to not complete?
Expert:  roy replied 1 year ago.

a drive cycle is a very specific way of driving the truck to get the monitors to set. just driving like you normally do will rarely set all the monitors,. it takes a trained tech to take it for the drive cycle and put it through all the steps to make the monitors run. it is well worth the 1 hour in labor to let someone set them for you.


Customer: replied 1 year ago.
Can you tell me how to do it.?I've already replaced the Cat converter and had it to the smog shop twice. I'm to save as much as I can at this point.
Expert:  roy replied 1 year ago.

it would be much easier to talk you through it than do it in this forum.


Customer: replied 1 year ago.
I'll take it to the shop on Monday. $44 is too much for a phone call that might not fix it. Thanks anyway.
Expert:  roy replied 1 year ago.

good luck. the charge for doing the drive cycle will be much more than that