04 Matrix failed etest - Toyota Nation Forum : Toyota Car and Truck Forums

steve4toy · 12-13-2009, 11:10 AM

Hi guys, I have an 04 matrix XR , 204000km .Failed etest very high No [1592] to pass should be below 505 .Hc passed at [2] limit is 66 and Co [0] limit is .37. Any solutions out there.

mikered30 · 12-13-2009, 01:23 PM

That NOx is very high. Do you have any check engine lights? High NOx can be caused by a bad O2 sensor, bad catalytic converter and some other things.

There are a few things to try first before looking at O2 or cat problems. If the air filter, spark plugs, and pcv were not changed in a while, I would look at them first. Will you be doing this work yourself or with a mechanic? PCV valve is very important, make sure you get it from the dealer, you must give your VIN when ordering it.

Clean the throttle body and MAF, run tank of shell or chevron gas (highest octane) for at least a week with a fuel system cleaner (Redline, regane, or Techron), and then change the oil. Check for vacuum leaks. The day before the retest, run the car very hard (ie Italian tuneup) on the interstate for at least 45 minutes. Schedule the test early in the morning on a cold day.

I would at a minimum change the plugs and PCV valve and run a fuel system cleaner with high octane gas.

steve4toy · 12-13-2009, 06:02 PM

there is no check engine light on. will do the work myself . will try the mimimum first . will stay in touch. Thanks .

circuitsmith · 12-14-2009, 07:13 PM

Maybe a clog in the plumbing to the EGR valve.

mikered30 · 12-14-2009, 09:37 PM

Most times when high NOx is encountered in emissions testing, the first thing to do is to clean the EGR valve, but with the design of the VVTI engine, an EGR valve does not exist. Changing the PCV valve may provide the best attempt at correcting high NOx levels, besides the plugs.

XR2003 · 12-15-2009, 01:58 AM

+1 on the PCV - also while you are at it, clean the throttle body and intake manifold (purchase a replacement gasket in case the original intake manifold gasket is extremely worn).

I had a CEL the dreaded P0420 - bad cat,. converter supposedly. Then when it came time to do a smog check - with some mineral spirits and t/b cleaner - I cleaned the throttle body and intake manifold - with no other major changes done.

A month later and no CEL since the cleaning - I got the car smogged and passed easily.

Keep in mind in all this is that even a dirty (oil vapor) intake manifold after over 90k miles and/throttle body can trigger (or not trigger) a false read CEL.

To avoid future oil vapor gunk - I installed an oil catch can (from the PCV to the oil catch can back to the intake tract right before the throttle body).

Some would say it would be waste on a normally aspirated car - but I can vouch for the fact that after 6 months - I have had about a quart of oil vapor blowby in the can - that would have been in the intake tract. Yikes!

circuitsmith · 12-15-2009, 10:29 AM

Quote:

Originally Posted by mikered30

with the design of the VVTI engine, an EGR valve does not exist.

Thanks, I've learned my new thing for today.

I was pretty familiar with the systems on my 88 Accord after the 16 years I owned it. But my 06 Matrix only has 17k miles so far, and I'm not the gearhead I once was.

steve4toy · 12-15-2009, 07:32 PM

working on the fix, toyota had too order the proper pcv valve . will know by friday.

steve4toy · 12-29-2009, 08:13 PM

Hi to all. did the basics as suggested, changed plugs and pcv valve [all genuine toyota parts] and ran a higher octane gas. Passed my e-test with flying colours. Thanks to all of you who helped

mikered30 · 12-31-2009, 07:51 AM

great, glad it worked.