Hi everyone,

I am getting a P0685 DTC error code. I have cleaned the battery terminals and driver side ground cable from Engine to chassis. That took care of the error code for two days. Today, the error came up again. I noticed there is another ground cable from the engine to chassis on the passenger side as well.

I want to know where ALL the ground cables are on this car. Can you please point me to a diagram or location of all the other ground cables? Apparently there is at least 5 of them per honda mechanic.

Thanks

 

Torontob,

Here is a diagram depicting the under hood ground wires on a '09 Civic:


*diagram courtesy of hondapartsnow.com; all rights reserved



You can find all of the ground wire diagrams for a 2009 Civic in the link:

2009 Honda Civic Wire Harness diagrams

The link sends you to the first "wire harness" components listing but the other three are listed below it in the "components" box located on the left hand side of the page.


Hope this helps!

 

Thanks TechTalk. I seen this diagram. I explored through the wireharness 2, 3, and 4 as well. I am not sure if it's my inexperience or if the diagrams are not really clear. So, I have the following questions:

1- I am getting an ECM/PCM Loop Open. Error code P0685. Could this be related directly to a ground wire connected to the Engine Control Module or it will be probably any of the ground wires in the car?

2- There is a defroster and door ground, etc....I don't think these are what I need. I have already cleaned Battery (-) ground to chassis. I have cleaned left and right side of engine ground wires to chassis. Do you know where the Alternator and Radiator ground cables are? Are they hard to reach?

3- Are all engine, alternator, radiator, and transmission grounds reachable by opening the hood and are they all in the first diagram which you posted above?

Green in picture is below is what I cleaned (I think my labeling of the component/area is right) - Red is what I have no clue about - What component do they attach to and where are they? I looked under the hood but I am at loss:




Thanks again

 

Anything guys?

Thanks

 

When you aren't getting steady power from the battery, there are likely to be spurious codes set.

 

Stupid car died on me today again. This time for good. Didn't turn on waiting 4 hours....Why am I not getting steady power from battery? well, maybe I am getting that but the grounds are not good so there is a shortage. And it seems that one has experience with this model. No one can point out to me exactly where the ground wires are despite posting the diagram above.

The car battery is a 430 coal caliber or 330 (whichever is closer to a new battery) and the idiot at the dealer told me they would have to change that and then do an AVR test $39 and charge $102 for diagnostic on top. Isn't there a law in Ontario that says Diagnostic fee should be refunded or applied to the problem when a problem is found?

 

take your battery to autozone or somewhere similar that'll load test to make sure it's still good. If it is you need to make sure the wire contacts on the battery are clean/corrosion free.

if your car doesn't turn on it doesn't mean your grounds are bad. Bad grounds usually just cause rough idle, rough running engine. But, just a guess, there's probably a ground cable somewhere on or around the valve cover, transmission case, and obviously on the battery.

take the cover off the fuse box and see if you got any moisture/corrosion build up on any of the fuses or relays. You obviously are having electrical issues, could be a relay...

 

If there is a cable disconnect btw car and battery then emergency lights won't turn on. I cleaned three ground wires mentioned above last months and problem went away. I can't find ECU and Transmission ground wires (so maybe they are corroded as well). Battery is not the issue as I should see dash light when I try to boost the battery but I don't. So, it's a disconnect but I dont know what.

Are the emergency lights directly connected to battery? where do they feed from?

It could be relay issue but it would be helpful if someone can point me to how to take off the bumper to check the ground wires there...

 

So, the dealer called and said that the Main Fuse had a screw missing holding it down so it WAS DRAINING THE BATTERY.

It is true that a screw was missing (the fuse has two screw on two sides of it) as my brother during the first year blew the fuse by boosting the battery by conecting RED to BLACK...

They say it's all good now and I should be on my way. I understand what he says and I kind of see that as the problem now, however, I want to take your input on this as well. Because one screw still held the fuse place very very tight and why the behaviour was so random and different time or after driving the car for so long it happened?

Any input is much appreciated.

 

You need both screws secure to reliably complete the electrical circuit. This was probably the problem with your car all along. I'd take the fuse out and check for any melting or burning on the contact point that didn't have a screw. If the fuse box is damaged, replace it. The whole box is not real expensive.