My car failed emissions due to high NOX. Plus my CEL gave me an EGR lift code. I cleaned the EGR valve and the EGR intake manifold. When I supply vacuum to the EGR valve at idle, the engine dies. Also, when I apply 12v to the EGR vacuum solenoid via jumper wires, with the engine at idle, it dies. Both seem to be working correctly. I reset my computer via the radio back up fuse, and the next day I got an EGR code again. What tells the computer to activate the solenoid and provide vacuum to the valve? Is there anything else I'm missing?

 

So you removed the plate near the fuel injectors and cleaned out the ports on the intake manifold?

Follow the vacuum hose from the EGR valve to the EGR control devices. Make sure the vacuum tubing isn't damaged and creating a vacuum leak along the way.

The reason you are getting an EGR code is that the ECU tell the EGR control valve to open the EGR valve (it uses vacuum to do this). The ECU monitors how high the valve lifts on the EGR valve. If the EGR valve does not lift high enough, then you get that EGR code. The ECU does not directly lift the EGR valve.

If you have a vacuum pump, then see if the EGR valve will hold vacuum as well.

 

At what point does the ECU send the signal to the solenoid to open the valve. I should be able to read 12v at the solenoid plug when the engine meets the right conditions. How can I simulate this and check that the ECU is sending the required voltage to activate the solenoid?

 

Do you have one of the hand held vacuum pumps with a gauge on it?

 

I beleive its from 1800rpm to 3000 rpm if this is what your talking about. Thats when your silinoid applies vaccume and lifts the egr valve. I beleive anything under that there is no vaccume and above that i think vaccume shuts off because it is fully open...... But im not 100% sure thou

 

I do not have a hand held vacuum pump. I can "barrow" one from the auto parts on their loan a tool program. When I force the EGR open by applying a direct source of vacuum, or by energizing the solenoid with jumper wires, I can reach under the EGR and feel it lift. Plus the engine dies at idle in both cases. But I still get the EGR code from the CEL and it has failed the NOX test twice. Once before cleaning the EGR and intake ports, and once after. How long does that rpm need to be maintained before the CEL sends voltage to the solenoid?

 

I'm still at a loss here. I'm not getting any voltage reading on the plug to the EGR vacuum solenoid at any rpm. What now? Help!

 

send me a pm with your email address and i'll get you code 12 diagnostic procedure.