On certain models in colder climates the Check Engine light can set due to moisture in the Manifold Absolute Pressure (MAP) sensor freezing. The MAP sensor needs to be replaced and on some models the intake manifold needs replacing also.
Car Problem Reports
Honda Civic Check Engine Light Due to Moisture Freezing in MAP Sensor
Honda Civic Problem
Average Mileage: 153,800 mi (107,000 mi - 254,000 mi)
Visitor, 1996 Honda Civic, 254,000 mi
Check engine light comes on reading map sensor when it reaches temepatures below 40 degrees. I have replaced map sensor twice in the last year and still have this problem i was told to clean the trottle body. Maybe this info will help someone else out there. I havent cleaned the trottle body yet but plan to very soon in hopes that it will fix my problem. P.S. youtube has video on how to clean the trottle body.
Visitor, 1996 Honda Civic, 120,000 mi
Extreme temperature change usually triggers the ck eng. lt on. also cold and humid temps. While the lt. is on the car runs rough, irratic idle, and hesitates. Have a mechanic turn off the lt. it's okay until another extreme temp drop off, or snow or rain.
check engine light.po420 and po171
Visitor, 1996 Honda Civic
MAP sensor caused smog to fail, exchanged for a salvage one for next to free. easy fix.
The check engine light came on about a year ago, when I was returning to Kansas City from Columbia. It was on for about 8 months, went off for a week, then came back on for 4 months. It has been off for about a month now. The Honda dealer wanted to charge me a $100 just to "evaluate" the problem. How can they NOT know about this?
Visitor, 2000 Honda Civic, 130,000 mi
same problem on my honda civic too.