1998 Honda Civic Ecm

104,000 MILES • 4 CYL • 2WD • MANUAL
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SKING22
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I recently went to get my emissions test and some problem codes came up two saying the primary O2 sensor was bad one saying the catalytic converter was bad and the last one saying the car was running lean. So I took it to the mechanic and he cleared the codes and for some reason it was saying not ready on the computer that they use to test your car.

So he looked at the computer and there were no volts going to the primary sensor. So he pulled the primary O2 sensor and it turns out the rear one was in the front one and vice versa. And so the rear one and front one both worked when they were plugged into the primary spot. So I know its not the O2 sensor that is bad so then the mechanic looked and he said it went to a closed system and would not go back to an open system and that the volts stay at zero after the car starts up after a few seconds.

I checked the fuse and it is not burnt out or anything. He told me that its probably part of the ECM burned out that grounded where the primary sensor would go.

The other thing that is weird is that I have driven my car for about 400 miles since the codes were reset and none of them have come back up and all the systems still say not ready.

something else that is random that i have no idea why but the car before the mechanic switched the O2 sensors positions I was getting 27 mpg now i just filled up today and now im getting 34 mpg.

So do you think I need a new ECM?
Mar 8, 2009 at 6:22 PM
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KHLOW2008
  • ✓Experienced Mechanic
  • 41,812 POSTS
Hi sking22,

Maybe not. Try resetting the ECM and do road test again. Does the radio loses its memory after turning off engine?
Mar 14, 2009 at 9:33 PM
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SKING22
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The radio does not lose its memory after turning off the engine. I have not reset the ECM cause I don't know how. I am a little bit worried about doing that since I have never even tried to do it before, is resetting it fairly easy?
Mar 26, 2009 at 7:06 AM
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KHLOW2008
  • ✓Experienced Mechanic
  • 41,812 POSTS
You can do the reset yourself but take note of the following. PCM RESET PROCEDURE/CLEARING DTCS NOTE: Before disconnecting battery or removing specified fuse, obtain anti- theft code for radio from vehicle owner. After battery or fuse is reconnected, CODE will appear on radio display. Enter 5-digit code to restore radio operation. If code is entered incorrectly 3 times (on CR-V, ERR-E will display), leave radio on at least one hour, then enter code correctly. If correct anti-thief code is not entered after 10 attempts, radio will lock and must be returned to manufacturer to unlock. Any time radio power is lost, pre-selected radio stations will have to be reset. For specific setting information, see vehicle owners manual. Powertrain Control Module (PCM) can be reset, which clears DTCs, using a Honda PGM tester or OBD-II scan tool following manufacturer's instructions. DTCs can also be cleared by removing specified fuse for 10 seconds from fuse/relay box. Obtain radio anti-thief code and record radio presets before removing fuse. Turn ignition off. Remove No. 47 BACK UP (7.5-amp) fuse from underhood fuse/relay block. After replacing fuse, reset radio anti -theft code, pre-selected radio stations and clock.


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Mar 27, 2009 at 3:14 AM
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