Looking for suggestions on Civic VX O2 sensor problem...
 

I just recently purchased a 1992 Civic VX with about 156k miles. Long story short (and why I'm posting on this thread), the CEL was lit when I bought the car which turned out to be code 48 (LAF).

I tried cleaning the sensor by soaking it in Seafoam for about 12 hours but that didn't do anything. However, I was able to find one at a pull-it-yourself junkyard that happened to get a 1994 VX in that day. I'm not sure of the mileage on that car as someone pulled the dashboard cluster.

Well, after physically comparing the sensors, I swapped them. Unfortunately, the CEL is still lit but it's no longer code 48. Upon jumpering, the CEL blinks on for 1 second, off for 3 seconds, ad infinitum. There are no short blinks. I tried clearing the ECU by pulling the backup 7.5A fuse twice to verify. According to the repair manual I have (1st Ed, 9/91), code 1 (if that's what it interprets to) indicates the Oxygen Sensor for D15B8, D15B7 & D16Z1 engines. My engine is etched with D15Z1.

So I took a closer look at the two sensors. Both sensors look exactly the same: 5 colored wires going to the same plug slots. The only difference is my original one had no markings on the sensor itself but the "new" one only says "L1H1" & "Made in Japan."

Before I dished out the fortune required to buy a new one, I wanted to check with those more experienced than I for any other things I could try.

Thanks!

-Jeff

P.S. I noticed in a forum about the O2 sensor socket being a pricey item. I found that my local Harbor Freight had both a deep socket version & a crows foot version for $5/each, the latter of which was on sale for $4. It works like a champ.

Re: Looking for suggestions on Civic VX O2 sensor problem...
 

Your new LAF sensor is the correct one. It should have the made in Japan and L1H1 stamped on its body.

As to your mysterious new CEL. Makes no sense to me why a P07 ECU would ever flash a code 1. Especially if the CEL 48 was there before. If all you did was replace the LAF sensor there shouldn't be any other problems that would be O2 sensor (the VX has a wide band LAF sensor).

There are web sites that have the Helm service manual on pdf. If you do a search on my prior posts you should find a link I provided. The Helm manual does a good job of explaining all the CEL codes and helps you track them down to the source.

In the meantime, who the hell knows what your VX is up to. How it can only have 156K miles after nearly 19 years is also interesting. But then again, some people don't drive very much.

Re: Looking for suggestions on Civic VX O2 sensor problem...
 

Hi,

Actually, I misread it; it was a code 10. It turns out one of the wires on the harness to the IAT was broken close to the plug. When I went to pull the plug out, the other wire broke. Long story short, I had to replace the IAT along with the wires all the way to the main wire bundle. Once I did that, the CEL went off and my next fill up showed 48 mpg!

Thanks!

-Jeff