Rep Power: 0

I just replaced the oil pan and passenger side axle on my 1999 Civic EX 2DR.
I did have to disconnect the exhaust at the A-pipe to get to the oil pan.
As soon as I started the car up for the first time after the repairs, the check engine light came on (in 50,000 miles that I have had the car, I have never had an error code until now). My gut tells me that I messed up the wires going to my secondary oxygen sensor (as I didn't support the exhaust that well).
I will be checking the actual codes later this week, but I was wondering if anyone else has had similar issues before.
Thanks

 
Rep Power: 517

Ya, if your work caused sensor wiring to be pulled stressed or yanked, you could have caused it.

Double check, maybe it can be fixed somewhat cheaply. Maybe not.

 
Rep Power: 0

I pulled the code today. It is "P0135 - O2 sensor heater circuit, bank 1 sensor 1". It seems like this is the primary sensor, however, the only sensor/wiring that would have been stressed would have been the secondary sensor under the car. Any ideas?

 
Rep Power: 0

I am even wondering if stress on the wires could have pulled a pin out of the electrical connector and if that is the only issue?

 
Rep Power: 517

BOTH sensors should be under the car on an EX. One sensor (primary, B1S1) is ahead of the catalytic converter in the pipe you had to disconnect, the other (secondary, B1S2) is screwed into in the middle of the cat.

Get under there and take a look!

 
Rep Power: 210

Might want to disconnect both the primary and secondary o2 harness connections and spray both male and female ends with electronic cleaner/lube then reconnect. Make sure to to do an ECU relearn afterwards.

I did this 4 months ago with a speed sensor and connection and haven't had an issue or CEL light since.