Charging Issue, Need help

[VtecYoo]

Hey guys so I’m not getting any power to 2 of the 4 wires that go to the alternator connector, the white & red stripe and the white & green stripe wires, the other 2 are good, and yes the big white positive wire also has power, car does not charge because of this issue, will turn on and car runs off the battery for a while until eventually it will die, looking for help plz, thanks!
I know the 2 wires that don’t have power coming have to do with the ecm & pcm, maybe computer? But does not make sense to me, any help helps, thank you

 

[nd4sped]

What kind of voltage do you have at the battery when the car is running? is it 14.7v?

 

[VtecYoo]

anywhere from 11 to 12 while running, since it’s just running of the battery, but it’s weird tho because I bought the car 2 months ago with that issue and drove it 1 hour back home with the battery light on with 12 volts

 

[nd4sped]

Sounds like the alternator has died. But also check the alternator belt to ensure its not missing or worn so badly that its not properly driving the alternator. If this is all tight then I would recommend removing the alternator and taking it to your local auto parts store like Orielly's, Advance, Napa or Autozone. They have free alternator testing services.

If the alternator test passes and you don't trust the results, you can also do an independent test with a hand held drill to test output. This requires an additional lead and jumping connectors. There are good YouTube videos on how to do this.

 

[VtecYoo]

Yeah I know I’ve already replaced the old alternator with a new one but the alternator was never the problem, the problem is I’m not getting power from 2 of the 4 wire that go to the alternator plug, the white with red stripe and white with green stripe wires, which are the FR signal and control signal for the voltage. Also replaced the ELD, same problem

 

[nd4sped]

Test those circuits for continuity or if you have spare good known ECU, swap it in and see if it resolves the issue. If issue persists with GK-ecu then go back and double check continuity.

 

[VtecYoo]

Yeah that’s my next step to change the ecu, don’t have a spare one but I should be able to find a good used one, and what do you mean by continuity?

 

[nd4sped]

Yeah that’s my next step to change the ecu, don’t have a spare one but I should be able to find a good used one, and what do you mean by continuity?

Continuity means resistance. If there is high resistance or absolute resistance in a circuit then that means there no continuity in the circuit. A good circuit should have low to resistance or good continuity.

 

[VtecYoo]

Oh okay got cha, I’ve never dealt with any circuits before so I’ll probably just change to a different ecu, i do find it strange since the car does have less than 100k miles on it, is this something somewhat common or often possible for that to cause a no charge

 

[nd4sped]

Oh okay got cha, I’ve never dealt with any circuits before so I’ll probably just change to a different ecu, i do find it strange since the car does have less than 100k miles on it, is this something somewhat common or often possible for that to cause a no charge

Not really a common thing at 100k. To check continuity you are simply putting the probe at one end of a circuit and the probe at the other end. You want near 0 resistance OR exactly or close to the specified resistance in the service manual.

Since it's a 6th gen Civic you can find the ECU's in salvage yard readily as they are OBD2 ECU's and nobody modifies them. In other words you should not have trouble finding one. Most ECU's in salvage are in good operating condition. Just do a good inspection of the case and make sure there has been zero water intrusion on the donor ECU.

 

[VtecYoo]

Oh ok sounds good, thank youu btw! I’ll keep you posted after I replace the ecu