Remember the EGR system i mentioned on the CRX? It be on the friz yo. The helicopter fish is a blazin', and the code is 12- EGR malfunction.

I've uploaded the diagnostic flow charts for anyone interested. The first chart (1 of 3) has a wrong spot in it. I've also uploaded my revised version.

So the first thing you do is to check the EGR valve by applying vacuum. The EGR should hold vacuum and the engine should stall or run poorly. Mine held vacuum, but the engine ran the same. At this point the flowchart tells me to replace the EGR valve... so I revised the chart.

Then I set out to clean my EGR intake runner ports.
On many vehicles this is pretty straightforward.... just nuts and bolts, and occasionally easy access... not on mine. I have to use a drill. Honda decided to weld over the access plugs (like freeze plugs).

I had an extra intake so decided to use it. I didn't know if it was plugged up or not, but decided to clean it out regardless. I saw a write-up where someone ground all the metal away down to the plugs, removed them with a slide hammer, cleaned, and then installed new plugs and JB welded over them. That's a whole lotta time and some extra expense. It's my car, and I can fix it right my way. I drilled 3/8" holes and then filled them with JB stick (radiator/fuel tank repair) after cleaning... and of course this manifold was already pretty clean.

pic-welded over port caps

pic-holes drilled

pic-JB stick. kinda hard to see. I could've used any brand radiator repair stick, but JB weld seemed suitably redneck.

So now I've got the cleared out intake on. The other one i quick-checked just to see how gooey it was... pretty nasty. This one will need oven cleaner and compressed air to clear it out.

But of course I still have the code 12 coming on when I drive. I go down the flow chart again. The EGR holds vacuum AND the engine stalls w/ vacuum applied. YAYYY! oh, umm... Back to the flow chart. My "EGR Control Solenoid Valve" isn't clicking. It's located on the firewall. I've got one coming from Honda @ $95. Hopefully I'll be done flowcharting then. And I saved myself from buying an EGR valve which I didn't need. I also checked the Lift Sensor located on the EGR valve to make sure it was good. A bad one would require the EGR valve to be replaced anyway...@ $170. The Lift Sensor check is further down on the flowchart.

Flowchart:

1 of 3:

2 of 3:

3 of 3:

Scott's revised 1 of 3

flowchart sections are sized for print. Not responsible for flowchart content (they have the lift sensor wire colors wrong too)

Note for mechanics: After some research, I have found that the ECU might not have set the code even though the runners were clogged -as long as everything else is working. It looks to the Lift Sensor and determines if it is at the correct height according to MAF sensor input. presumably you could have no code and still have high NOx emissions from this problem and reduced fuel mileage, possibly even a miss or stumble with a partial clog... See this OBDII Prelude TSB (pdf file)
Download file
So in reality, the flowchart to 'clear this code' might be 'correct enough' to do so, unless you replace the EGR valve for no reason (in which case you might go in circles forever following the first few steps). But we all know it oughta stall with that test, right? ... so that helps.