JMKendrick

Hey all,

I am looking at buying a 2001 Civic EX that has some issues. I am trying to figure out what exactly the issues are before I hand over the cash.

The first issue is no charge from the alternator. The car has a 3 month old battery and a 3 month old Autozone alternator. Apparently the car had no charge before and the owner had a friend replace the alternator, but the new one isn't charging either.

The alternator and 80-amp fuses are ok. The belt is fine and the alternator is spinning. However, if I remove the hot wire and measure the output, it is only putting out about 4.6 volts.

Additionally there is a code 1298 that sets immediately after being cleared. Discription says Electrical Load Detector circuit high input. But I don't know if the ELD is really causing the issue or if the code is just being set due to other charging issues.

I have been told that the input from the ELD is ignored by the computer if the high beams or a/c is on, and the alternator would be commanded to output maximum charge. Not sure if that is true or not. Regardless, the alternator does not charge the battery when they are on either.

I guess the question is, do I fight with getting the alternator out and taking it somewhere to be tested? I guess it shouldn't be too difficult to get out since it was replaced 3 months ago. Or is it possible a bad ELD could be causing this issue?

Thanks,
Jeff

emich

Get a jump cable and connect the negative battery terminal to the body of alternator. This way you are checking bad ground connection or loose alternator bolts

JMKendrick

No change using jumper cables. I have also checked continuity of ground and the cable from the alternator to the battery and is all good.

I took the alternator out and successfully bench tested it at 2 parts stores. I have rechecked the 10amp fuse under the dash and the 2 large fuses around the ELD. I have also done the diagnostic on the ELD and get the correct readings (12v on 1 pin, ground on the middle pin, and 5v from the computer that gets pulled down to 1.5v to 2.5v when I turn on the high beams and /or the air conditioning) .

I guess the next step is to look at the 4-pin on the alternator to see what is there as far as signals from the computer and power for the field.

Jeff

JMKendrick

So at this point I am at a loss. I replaced the ELD with a new one even though the old one seemed to be working correctly. No change. I have done the tests in Alldata for the wiring from the ECM to the 4-pin control harness on the alternator and they all seem fine. So at this point I was thinking maybe it was the computer.

The problem is the alternator would sometimes run in high-output mode for a couple minutes after you start the car, but it doesn't seem consistent as far as I can tell (hot or cold start, etc).

I read from a couple sources that the alternator really needs only the 12volt black wire in the 4 pin connector and the output wire connected to operate. Everything I have read says the alternator should run in high-output mode with those 2 wires hooked up. I also read that the alternator outputs 12v on the white/green stripe wire which goes to the ECM (which I tested good continuity with no shorts to ground) and the ECM drops that voltage to ground through a diode when it wants the alternator to be in low-charge mode. If the ECM is not grounding the white/green wire, the alternator should be in high-output mode.

So I actually physically disconnected the white/green wire. And the damn alternator STILL doesn't go into high-output mode. At this point I am not sure if the alternator is even putting anything out at all, but I ran out of daylight to test further.

I guess at this point I will pull the alternator out and get it tested again just to ensure I haven't blown something up in it, but other than that I am at a brick wall here. All the fuses are still OK and I still get the 12v on the black wire from the ignition key. Ground at the alternator is OK and all the battery cables are good and have been cleaned and reseated.



Jeff

JMKendrick

Well after more testing I pretty much figured out that the alternator was failing once it or the engine compartment got to a certain temp. It would charge for a few minutes then stop, if I shut the car off for a couple minutes and restarted it would charge for a shorter time, repeat until finally it wouldn't charge at all. Then the next morning it would work again.

Replaced the alternator and it's charging fine now.

On to the next issues, I'm sure I'll be posting more here lol