NACvicSi

1997
Honda
Civic
CX - hatchback

I picked up a "new" hatch so I could sell my Del Sol. It's throwing a code 41 for primary oxygen sensor heater. I bought a replacement unit and began to change it today. As I pull the exhaust shield back I notice a long/large crack running from the 02 sensor round through the runners. Could this be the true cause of the CEL? I don't want to put the new O2 in if so as I can just return it unused and put that money towards fixing this.

NACvicSi

Oh and I missed the 98-081 service bulletin by two months which would have replaced the manifold, cat, plugs, plug wires, dizzy cap/rotor, oil change, and oxygen sensors for free. :rage:

Former User

Though you clearly need to replace the exhaust manifold, it would not throw code 41. Start by checking whether 7.5A dash fuse 15 is blown and whether the primary O2 sensor plug has battery voltage with the key in ON(II). Also measure the resistance across the two sensor terminals for the heater element.

Hondenver

just a word of advice when you go to replace the manifold find you a stock y8 manifold they are tubular instead of cast and def. flow better and are cheaper than aftermarket.