I am trying to diagnose an EVAP leak and I am running out of ideas. Following the diagram here: https://www.toyotanation.com/media/2000-camry-2-2l-vacuum-diagram.57333/

if the solenoid is working properly it should be closed when the car starts and is idling, correct? Then if I apply vacuum with a pump to the line that is plugged into the Q end of the modulator, isolating the modulator then the car in idle shouldn't stall correct? Because the solenoid is closed. Otherwise it means the solenoid is open. Note: I am not applying vacuum to the nipple of the Q end of the modulator but to the hose that is connected to the solenoid.

Therefore, if I apply vacuum to the EGR valve nipple the car should stall.

I have replaced the air intake hose that had was broken, and I have checked the vacuum lines and I still can't find the leak.

The DTC code is small evap leak.

Do you have any other suggestions to diagnose this leak?


  • P0400 is a generic code for EGR, not an EVAP leak. You're combining things into two and coming up with the wrong answer. To check if the EGR is working correctly, you just have to actuate the EGR by either manipulating it manually (pressing on the diaphragm with directly with your finger) or pulling a vacuum on it through its port. This will change the tone of how the engine runs, but shouldn't come near to stalling it. You're just looking for the change in the sound of the engine. Easy test and no stalling involved. Dec 15, 2022 at 11:50
  • I checked the EGR valve and the vacuum modulator with a vacuum pump and both work. I'll hook up the scanner again, to verify the code I am getting. Dec 15, 2022 at 20:22


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