Possable fix
The egr valve on that motor has a egr positioning sensor mounted on top. The sensor goes bad and the ecu can't determine the how far the valve is opening so it opens it too much. This causes surging of the engine under light throttle application. Also as stated above the egr can stick causing rough idle. Either way if you get the valve from the dealer it will come with the sensor solving both your problems.
Its either your egr valve, the egr vsv, or the vacuum modaultor, you will need a vacuum gauge and a scanner to test which you need.
1,778 views
Usually answered in minutes!
P0402 indicates an excessive EGR flow condition.
I would check to see that the EGR is closing properly.
Does it idle rough?
Excessive EGR would give you a bad idle, or a stall at idle if it was stuck open. Try This: Tap the top of the EGR valve with a small hammer, see if the idle improves. Please respond.
I copied and pasted the previous paragraph because I have same prob
Yes, I have 96 Avalon with these exact symptoms. Car starts and runs good until it warms up....like after running highway speeds and then slowing down to traffic lights, then Car idles really really rough. Almost like it wants to stall. I did tap on top of the EGR valve and it comes back to regular idle.....but then drive around the block and it is rough idle again. When this first started happening I did not get a CEL light that was coming on. But after a couple of weeks I now have the light on and when I do the code check it comes up with P0402.
P0402 indicates an excessive EGR flow condition.
I would check to see that the EGR is closing properly.
Does it idle rough?
Excessive EGR would give you a bad idle, or a stall at idle if it was stuck open. Try This: Tap the top of the EGR valve with a small hammer, see if the idle improves. Please respond.
×