I have a 1991 Honda Accord SE, automatic trans with a #12 code which is a generic EGR code. I have manually cleaned the EGR valve, used seafoam, vacuum and manually tested it. The valve holds a vacuum and the engine stutters slightly when egr is applied during idle. So from what I know that means the valve is good and the ports are clear.
The part that I am hesitant on is how much should the engine stutter when I apply the egr during idle? Mine is an audible difference but not close to stalling. Could the ports still be the cause? How can I test if the EGR is receiving vacuum while driving? I know the EGR is only applied when up to temp and speed. Is there a way to test at Idle? Can I apply brake and rev engine slightly while someone else checks the hose for vacuum? Any help to clear this code would be great!!!
12 EGR – exhaust gas re-circulation lift valve
You are on the right track. Keep chugging, I will help you out a little.
The code 12 you are getting is indeed an EGR code, but cleaning your ports out will not fix THAT problem. What you did will eliminate any hesitation you may have been experiencing. (Very common on that accord, especially around 1,800 rpm when car is warm)
The code 12 has to do with the selnoid on the firewall and also the EGR valve itself. Even though the valve holds vaccum. does not mean the valve is good. You see the valve has a “lift sensor” built into it. (this is the connector that you see on top of the valve) If the lift sensor goes bad, it will send a false reading to the PCM saying that the valve is not up, and in turn give you the code 12. There is a way to check the valve with a DVOM. I do not know the specs off the top of my head but you can almost bet your last dollar that it has a bad EGR valve. I have replaced quite a few of those myself. I would recommend you go to a salvage yard if you can’t afford a new one.
Good luck and thank you for the question.
Yes I saw this comment on another post and can see it was cut and pasted here. However it does not answer my question. PLEASE HELP!
1) Could the ports still be the cause? Yes
2) How can I test if the EGR is receiving vacuum while driving? You can not
I know the EGR is only applied when up to temp and speed. Is there a way to test at Idle? ScanTool or Engine Analyser
Can I apply brake and rev engine slightly while someone else checks the hose for vacuum? No
Any help to clear this code would be great!!! <-- See above comment
Thank you Jaxer. I also have a code 43 for the Fuel supply system. When i first came on I checked the O2 sensor and found a dirty connector that I had gotten oil on. I cleaned it out and the code went away after clearing. By the way the O2 sensor appears fine and is only about 6 months old. Could a faulty EGR lift sensor be the cause of that code too? I am just hesitant because an egr is so expensive and there is no way to be sure a used one has a good sensor. THANK YOU
Hello again… I tested the Lift sensor cables at the base where it meets the sensor and the right voltage is there… one is ground at 0, one is .5v and the last is 5v. Does that mean the sensor is good? or does that just tell me it is receiving the right voltage?
Just means it is receiving the right voltage.
How can I test if the Lift Sensor is good?
I have now suspended the car to be able to see if the EGR is receiving vacuum during driving. I came up with no sign of a vacuum on the gauge being connected to the hose from the solenoid (#16). Would that indicate a bad solenoid or could that still mean the solenoid is not receiving a vacuum itself? What could I test next? Any help would be great as I am still learning about the EGR system components.
UPDATE:
With the car idle I hooked the solenoid to the battery and to the gauge, now I was able to pull a vacuum so the solenoid is good. This means the solenoid is not being told to send a vacuum.
Sooo…
What sends the signal to the solenoid?? ECU, Lift Sensor, or ???
A used EGR fixed it… so it was the lift sensor!
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