1996 Honda Civic HX ERRORS P1164 & P0401, I have new O2 sensors!

koakamaka

New Member
I have a 1996 Honda Civic HX 5-speed. It's got a new battery. I gave it a tune-up & oil change: new plugs, wires, cap, rotor, air filter, oil filter & BOTH O2 sensors. The check engine light came on AGAIN after driving 55 miles. I'm still getting error codes P1164 & P0401!?! BTW, I'm getting roughly 30 mpg combined, but mostly highway.
 

koakamaka

New Member
thanks for the prompt reply. I'll have to get into the garage tomorrow.

Clean and scrape carbon out of the EGR valve and chamber.

What specific brand of primary O2 sensor did you install?
 


koakamaka

New Member
thanks! yes, I'm running generic O2 sensors, but the crazy thing is on the smog test, it would have passed were it not for the OBD error. I replaced the battery and was unaware of the computer needing to reset. Hence, I took it for the smog test. The car is running ridiculously clean! The emissions were so low, that my mechanic's mouth dropped. This made me inclined to think that the O2 sensors are good.
 


koakamaka

New Member
THANKS for all your advice! I took a look at the EGR valve sensor. It was really filthy. Then I took a look at the EGR passageways. The gasket was caked with black mountains, the passageways were filled & the the intake manifold's 4 plugs were PLUGGED. The holes looked like mini ANT HILLS! I had a difficult time cleaning the passageways. I used half a can of brake cleaner & went through 2 (I broke the 1st one while scrubbing!) toothbrushes while I let it soak in the brake cleaner. I was not sure I could even clean the intake manifold holes as the plugs were nearly solid! but I finally was able to work it out with my pick set. The fuel injectors were ugly filthy caked on too! Hopefully, now that I've given all this a thorough cleaning, the check engine light won't return! Maybe now my mileage will improve too!
 


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