Hi Folks,

I'm hoping someone on here can help point me in the right direction, as the Charging System Failure indicator light on the dash (looks just like a battery) will come on for about a second, then shut back off, wait a little bit then occur again.

The car is an 04 EX with leather, approx. 149,000 miles. I have owned the car for 7 years, bought it with 56,485 miles on it. Car has been flawless until October '16. Driving home from New York one night, I noticed the car had a whine from the pulley system (hoped it was belt going, but was wrong), and about 45 minutes into the ride the Parking Brake warning light came on. Next came the Supplemental Restraint System light, then the ABS light, etc. After a minute or two the entire gauge cluster went black. The next morning I took it to a mechanic who confirmed my thoughts that the alternator had died. Tested the system after installing the new alt. (don't know what brand) and said everything came out good, but warned me about the ELD Module being a problem in 7th Gen. Accords, telling me I should be okay as they tested for the module having failed, and it seemed to not be a problem.

Fast forward 3 months, upon starting the car to drive to work, I noticed that Charging System Failure light was on. Ironically, I work at a repair shop and as I pulled into the lot, the car died. All gauges were off, brake lights stopped working, engine would begin to stumble under loads, etc. They originally diagnosed the issue as a bad battery cable, saying that as soon as the touched the positive cable, it came off of the battery post. They ordered a new set of cables (both positive and negative) and "fixed" the current ones so that I could drive the car until the new cables arrived the following day. When I returned the following morning and told them that the CSF light came back on driving to work, they realized there was something else wrong. They proceeded to test the computers and wiring harness, as well as the charging system, finding the voltage regulator of the alternator was actually starting to melt some of the plastic, so they replaced the alternator (Denso was put in). As soon as the car acted up the first day, I told them about the ELD module problems and that my headlights have always shown the indicative flicker that points to a faulty ELD. They claimed to have checked for the signs per the Service Bulletin and didn't observe any, therefore it couldn't possibly be a faulty ELD module.

About two weeks later, I went out on a Saturday morning to start the car, and it was dead. Jumped it, let it run to charge up, and it would shut off and start again without much problem. Decided after draining the battery so low twice before this issue, that I would rather play it safe and put in a new Optima Yellow Top battery. Again about a week later, the light starts coming on for about one second then going out, going maybe two to five minutes between occurrences. Go to Advance Auto since it was the weekend, they test the battery and the 450 CCA battery comes back with 813 CCA...... They figured the voltage regulator had started to fail, and recommended a new alternator (CarQuest). So that's what I went with.

About four days later the damned light returns, so I had a local shop that I'm friends with dig into it, and they were running live diagnostics showing the alternator at 93% charge output at an idle with no load, and after looking at the Service Bulletin together, they recommended trying to replace the module itself (saving $350). That fix made it about two days, but they figured that the bad ELD could have hurt the alternator so we put in a new Denso alternator. That fix lasted about three days before the light started to come on, but it only does so on the way home from work, so we figured something in the fuse box may be having heat related issues (happens at the warmest point of day the car is driven, usually coming on at the first stop after a 20 mile highway drive). So we replaced the entire fuse box assembly with a brand new one from Honda.

All seemed well after the fuse box (which is what the Service Bulletin recommended to begin with). But alas, one week later the light has returned yet again. I am at my wits end over this, I have now had three separate shops look into the issue, and I can't keep throwing money at the issue week after week.

I'm sorry for the length of this post, but a lot has been done to remedy the problem all to no avail.

TL/DR: 04 Accord EX Charging System Failure Light comes on for about one second then goes out, repeatedly. Have replaced both battery cables, ground cable on passenger side of motor, battery, alternator (numerous times), ELD module (reusing factory fuse box assembly, and the entire fuse box assembly (new from Honda).

I'm desperate for help with this!!!

 

You have replaced almost every component in the charging system. You need to do some electrical testing to figure out what is going on with the charging system.

I'd disconnect the battery and unplug the electrical connector to the alternator. Look for signs of damaged/melted wires near the alternator.

There are some tests you can try with a volt meter. Not sure if you are doing the testing yourself or plan to take it to a shop for more diagnostics.

 

PaHonda,

If I remember correctly, when the battery cables were replaced, that included the wires going to the alternator, and the last time I had the car apart I did not notice and burned or damaged wiring. I also made sure to use a fair amount of dielectric grease when putting the connectors back into the bottom side of the alternator.

If the tests using the voltmeter are simple enough, I should be able to do them myself. Before I replaced the fuse box assembly I took a couple quick measurements off of the battery, by measuring off of the posts.

Engine off was around 12.79v.

Engine idling, all electronics off (no load) was around 14.43v.

Engine running at 2,000 rpm, defroster on, fans on high, rear defroster on, low and high beams on, radio on (trying to create a load) was around 14.26v. (had a second person in car while I measured the battery)

I can run these tests again since I had replaced the fuse box if necessary, or if you tell me any other tests to try I can give them my best shot. I have heard that my problem could be from not using a Honda genuine alternator, any truth to that?

Thank you so much for the help so far!

 

Denso usually makes good aftermarket parts, but anything is possible.

Start with the simple electrical testing on the wiring harness to the alternator.

The blk wire and the blk/yel wire at the alternator both should have 12V on the volt meter (use a good ground for your negative volt meter lead). The key should be in the II position when you do this test. You may also want to try with the engine running and alternator unplugged and repeat the tests.

I'm trying to figure out what the normal voltages should be on the other 3 wires going to the voltage regulator.

 

Going through the same thing. I’m guessing it’s the PCM. But I’m going to replace the alternator again just to make sure it wasn’t a bad alternator.

 

Hopefully I'm able to catch you before you go through replacing the PCM or chasing this any further.

I ended up putting a Honda OEM alternator in the car and haven't had a problem with the entire charging system since.
Been over 5 years and 100,000 without an issue