I have a 1988 honda civic and about a month ago the engine light came on. When I checked ECM I got a code 20. I didn't what to else to do then then clean the battery posts. The engine light disappear but went on again on before I got home. The next day I checked the ECM and it displayed a code 1. I changed the O2 sensor (with a Bosh part), however, and after I started driving the I received a code 20 again. The code would disappear after I turn off the car but would come on again after about 20 minutes or so. I can't afford to bring it to a repair shop so, I changed to O2 sensor again, with an factory O2 sensor - In the process I disconnected the battery and post battery terminal broke (positive cable) so I put on a new one. Now I getting a code 19 and then engine light comes on as soon as I start the car. The car seems to drive good or the same before all this started, except that since this ordeal started, I've notice that my gas milage has gone from 35/30 - 25/20 per gallon. Any advise would be helpful.

Thanks

Code 19 = Automatic Transmission Lockup Control Valve

If you suspect you are getting bogus codes, the ECM may be failing. This is not uncommon on older Hondas.

Code 19 = Automatic Transmission Lockup Control Valve

If you suspect you are getting bogus codes, the ECM may be failing. This is not uncommon on older Hondas.


Thank you Txgreasemonkey - I suspect it might be a bad ECM, but would that account for the bad gas mileage since the codes started? Also, I have an used ECM, are they difficult to install?

Thank you again.

Yes, it could account for the poor gas mileage. ECMs are easy to install. Here's how to save yourself a bundle:

https://www.askmehelpdesk.com/cars-trucks/faq-how-troubleshoot-repair-maintain-hondas-selected-other-vehicles-46563-3.html#post235038