Techstream EGR Valve Blockage Data

Mine runs every time I drive it. It is not too picky and the values have been high for years. The sensor is not laboratory grade; the value can change from 20-22 from one test to the next.

 

Before I cleaned mine it was showing 10 point something. 21 or 22 after cleaning.

My before-cleaning situation was both a gunky cooler and a rutted ski-jump in the valve.

 

The 20+ kPa you're getting means your system is not clogged. That's not unusual, even for systems that have not had the cooler cleaned. My car's, for example.
Of course values after cleaning are higher than before cleaning. That just means the cleaning was successful.
Toyota does define a minimum "good" number below which one should clean out the EGR tract. It's reported with the test result, like the 0.87 kPa (not PSI!) in rjparker's example above. However, many consider that value too low. You could arbitrarily choose 10 kPa as a more conservative safe limit.

 

Or, if you saw that 10 was a reading I had when suffering from both a somewhat gunked-up cooler and a rutted ski jump, you could decide you'd rather not wait as long as I did, and set a target number somewhere above 10 kPa and lower than 20.

So far, we have plenty of data on what "pretty good" numbers look like, but haven't really established a basis for any particular number to be the threshold where you want to do the work.

 

I still have no clue how that numbers are measured. Mine are jumping from 16 to 10 then to 14 back to 16 and so on.
Best was 19 after a partial EGR circuit cleaning (meaning intake manifold and EGR pipe).

 

This is a report from an XTool scanner. I can't find it in the prius specific section but it is in the generic OBD2 menus I had cleaned the intake manifold, EGR valve and cooler. I can open the EGR with the scan tool. It responds. The MAP responds to throttle and opening the EGR. It reads 97 at Engine off. It seems to be working but may be too slow. I can compare it to another Prius.

 

I ran the test on 2 other Prius. Value 16.25 KPa 2010 Prius 130K miles, Value 19.14 2011 Prius 120K miles. I replaced the EGR valve (Olathe Toyota online parts) I did not replace the valve at first because i was able to open it with the scan tool. Apparently it was intermittent. I had cleaned the cooler and the manifold ports. They were not completely blocked. After changing the EGR valve i got a value of 18.88 KPa and again 19 KPa. In the future if i don't find the ports and cooler blocked to a greater extent i will replace the EGR even if i can open it withe the scan tool. The EGR seems to be a six wire stepper motor. It would need a seal to keep exhaust gasses from getting into the motor. I assume that the seal was failing and preventing the motor from opening the valve every time. Amazon has the EGR for cheap but too many say they don't work. (maybe the ports weren't cleaned or maybe poor parts) Thanks to every one who posts good information on this site.

 

The mechanism is different and often sticks open right out of the box. Toyota improved the original design and has an ecm update as well.

Revised EGR-Valve is 25620-37120. The updated Egr-valve kit 04004-58137 offers the same valve at a deep discount.



Improved Toyota egr w housing number