Check Engine Light With O2 Sensor Fault Code on Honda Civic

Problem Description and Possible Solution

On certain models the Powertrain Control Module (PCM) can misinterpret the secondary oxygen sensor data and set a false Check Engine Light. A software update from Honda is needed for this issue.

Problem Data
RepairPal Verified
Average mileage: 125,868 (28,000–211,000)
3 model years affected: 1999, 2004, 2005
29 people reported this problem
Viewing 1 - 9 of 9 comments
My 2005 Honda Civic EX intermittently threw a p0135 code saying that the a/f sensor one was either faulty or something was wrong with the heater circuit. It also threw a p0141 code for 02 sensor 2. I replaced both sensors, but the MIL light comes on despite resetting the battery several times. Both sensors were brand new and OEM quality sure fit. I'm taking it to a local shop to have them do a detailed reading to see if it's not something else electrical or if it possibly the PCM.
The MIL is on. Codes P0135 and P0141 are reported for each sensor. The sensors have been replaced. The PCM has been updated. The fuse box has been replaced. The problem persists.

Honda isolated the problem to no communications signal at fuse 4 in the cabin fuse box and recommended replacing the fuse box. That was done along with all their other suggestions. All that has been accomplished is that Honda has drained more money out of my economy.
P0141 code, replaced sensors multiple times, checked fuses, wiring, measured O2 sensors w/ meter,computer o.k., just bought another sensor from dealer (no warranty...go honda!) going to replace sensor in cat. again. If it doesn't fix problem car is going for a downhill drive off of a short pier!!! NEVER OWN A HONDA AGAIN!
Check engine light reading 0s2 circuit
Same problem, it is not yet fixed.
replaced the oxygen sensor for 530 dollars
Took it to the dealer and they said the check engine light was due to the 2 - 02 sensors on the exhaust.
The one in front was somewhere around $20 - $30 I believe. I did that one and it didn't take care of the check engine light. The one in the rear is over $100 and I said I wasn't convinced that it would take care of the problem. Since then I have seen this on various internet sites saying that changing both of them didn't take care of the problem and that a software update was needed. I think it should be a recall. What does it take for it to a recall? Mine is still not fixed and now I have limp mode, no tach or temp guage, green flashing key problem. All from an alternator bolt that broke while driving on the highway. I'm trying to repair the ECU but not expecting to be successful. Right now it is driveable but the voltages on the ECU turn negative when the key is turned on. I think this is due to something on the ECU that is bad.
Engine light sometimes on - sometimes off. I don't trust the diagnosis.
Check engine light shows something about the o2 sensors and the ECT sensor. Car won't turn over and when it does, it revs up and idle sounds rough. I've had a lot of parts on it replaced but it has not fixed my starting issues.