Power lose


Asked by Aug 03, 2015 at 06:28 PM about the 2003 Honda Accord LX

Question type: Maintenance & Repair

2003 LX Driving at high way speed tach and speedo drop to zero charge light comes on
trip indicator flashes .Retrieved code P0 685. Has anyone seen this. Could a dieing
battery cause this .Alternator out put 14 volts.

10 Answers


Also when the above take place engine is not affected at first only after the check engine light comes on.


P0685 ECM/PCM Power Relay Control Circuit Malfunction - ECM power control circuit is open or shorted - Failed ECM power relay - Failed ECM If its not the ecu, as it's been replaced, it's likely the relay where the issue lies. also, check your battery terminals and connections. a lose feed line could cause power issues.


Is the relay replaceable if so where is it.

1 of 1 people found this helpful.

If the ECM/PCM malfunctions or becomes shorted. That would be constant and not intermittent problem. After clearing the code it didn't reappear after starting the engine.

1 of 1 people found this helpful.

trebor66 ...and what..is the problem fixed..still have code???


Kelly here is what I have done. After having the problem this morning. I charged battery installed back in car started it up checked voltage at terminals (14 volts at idle).My drive to and from work 20 miles +/- at about 5 miles to battery light comes on again and the tack and speedo drop to 0 for a moment no affecting engine speed doing 70 on free way.After a few get off freeway and now the check engine light is on and off with a little hesitation. Made it home access the code as stated earlier cleared it and checked the connections behind the radio(it had issues of not turning on no volume).Checked the system voltage with scan tool it showed about 8 volts +/- .Charged battery checked the battery connection found negative side clamp tight but could still turn it scraped clean and made it tight so it could not turn. Started right up turned on the A/C and headlights shut it off restarted no problem and no code .Your thoughts.


at this point drive it again... short maybe when driving have to see..ill think on it.. i get so many questions...

1 of 1 people found this helpful.
Best Answer Mark helpful

Honda's can be very temperamental when it comes to voltage. Having had similar problems but different codes over the years, my advice would be to change the battery, and then if still problems, the alternator . I have seen many alternators test out as good when in fact they are not.

1 of 1 people found this helpful.

Update Kelly and JP1956. Drove it this morning did fine till about a mile to same issue, but no code.Read JP's comment about battery. Replaced battery drove home with A/C going ......NO ISSUES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! I hope that fixed it thanks for all your help. Bottom line is a battery that is dieing could cause a lot of issues.The battery I replaced wasc 3 years old.


LOL hope you got a better grade of battery!

Your Answer


Looking for a Used Accord in your area?

CarGurus has 61,333 nationwide Accord listings starting at $999.


Honda Accord Experts

  • #1
    Tom Demyan
  • #2
  • #3
    Jonathan Ford
View All

Related Models For Sale

Used Honda Civic
797 Great Deals out of 76,594 listings starting at $888
Used Toyota Camry
1,062 Great Deals out of 70,872 listings starting at $750
Used Honda Accord Coupe
174 Great Deals out of 9,918 listings starting at $2,495
Used Nissan Altima
1,089 Great Deals out of 73,785 listings starting at $875
Used Toyota Corolla
898 Great Deals out of 65,121 listings starting at $1,000
Used Nissan Maxima
350 Great Deals out of 23,418 listings starting at $1,550
Used Honda CR-V
831 Great Deals out of 53,612 listings starting at $1,007
Used Acura TL
171 Great Deals out of 4,910 listings starting at $999
Used Hyundai Sonata
701 Great Deals out of 47,341 listings starting at $1,995
Used BMW 3 Series
1,021 Great Deals out of 31,251 listings starting at $1,000
Used Kia Optima
476 Great Deals out of 28,315 listings starting at $2,200
Used Chevrolet Malibu
1,225 Great Deals out of 77,349 listings starting at $1,500
Used Toyota Avalon
257 Great Deals out of 16,428 listings starting at $1,995

Used Cars For Sale

2017 Honda Accord LX For Sale
6,094 listings starting at $18,499
2016 Honda Accord LX For Sale
19 Great Deals out of 754 listings starting at $13,995
2015 Honda Accord LX For Sale
45 Great Deals out of 1,305 listings starting at $10,500
2014 Honda Accord LX For Sale
109 Great Deals out of 2,768 listings starting at $9,499
2013 Honda Accord LX For Sale
19 Great Deals out of 550 listings starting at $7,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.