Originally Posted by Ska-T

Thanks guys. The job is done. MIL is reset and hasn't come back on ... yet.

In case some beginner reads this later here are a few details not mentioned in the above posts. After the OBD II scan showed an error code of P0135, the electrical troubleshooting shown in the Honda Service Manual p. 11-157 was followed. My sensor had infinite resistance between terminals 3 and 4, thus it had to be replaced. I "borrowed" the oxygen sensor socket set from Autozone. That is, you buy the tool, but when you return it you get your money back. They give you 90 days to return it. Great program. Too bad the OBD II scanner is no longer included among their loaners tools in California (verified by Autozone). The car repair lobby didn't like it and our governor agreed with them. I took off the oxygen sensor cover (p. 9-12). It may not have been necessary, but it made it easier to use my socket wrench. Denso 234-4099 did not require any splicing of wires. Denso included a tube of anti-seize grease, which was nice. I used it on the sensor threads as well as the bolt threads for the cover.

Regarding reading ECU error codes via the Service Check Connector (p. 11-81), if I'm not mistaken the MIL flash is actually indicated when the light goes off. That is, the MIL goes from on to off to back on. The duration that it is off indicates whether that digit is a one or a ten. My MIL flashed off once very briefly (seemed like less than 1/2 second) indicating an ECU error code of 01 (not 10), and that was later confirmed by the OBD II code of P0135.


Any recommendations for an inexpensive OBD II scanner? I read that CAN scanners are required for newer cars. Is CAN backward compatible to a '96 Civic?