2003 Honda Civic



March, 9, 2009 AT 11:10 PM

Electrical problem
2003 Honda Civic 4 cyl Two Wheel Drive Automatic 134000 miles

After having the timing belt, water pump, spark plugs and air filter changed, my 2003 Civic is idling between 500-750 rpm and will shutter every couple of seconds. The battery voltage will drop to 12.3 volts when accelerating and at idle and returns to 14.2 when gliding. This has happened 1st day of driving after the above repairs and the 3rd day. Day 2 the voltage stayed at 14.2.

Is this an alternator or voltage regulator problem? Also, is it a DYI job to change just the voltage regulator or are the alternator and regulator sold together?



5 Answers


Dave H

March, 10, 2009 AT 8:27 AM

Hello .. thanks for the donation .. much appreciated

The alternator is replaced as a unit and is an esay DIY job ...Because of the work you have had done to the vehicle, I would be checking the wiring connections are secure and clean before replacing the alternator !! it sounds like you may have a loose connection .. hope this helps .. let me know

Ensure you have the anti-theft code the radio. Write down the frequencies for radio's preset buttons.
Disconnect the negative cable from the battery.
Remove the adjust plate mounting bolt "A", locknut "B" and mounting bolt "C". Remove the Power Steering (P/S) pump belt "D" and pump without disconnecting the P/S hoses. See Fig. 9 .
Disconnect the 4 pin connector "A" and alternator cable "B" from the alternator. See Fig. 10 .
Loosen the adjusting bolt "A", and remove the lock bolt "B" and mounting bolt "C". Remove the alternator belt and alternator. See Fig. 11 .
Fig. 9: Removing Alternator Components



March, 12, 2009 AT 6:50 AM

Thanks Dave, a big help. A bolt was loose (B in the alternator drawing) and this cause the belt to loosen.

Thanks for the thorough answer!


Dave H

March, 14, 2009 AT 5:14 AM


No problem .. that's why we are here ...feel free to spread the word of our forum to your freinds and family ... again, thanks for the donation and feedback .. and we are here should you ever need our assistance in the future !

Happy Motoring



November, 4, 2011 AT 2:06 AM

Hi Dave, I am trying to install a new alternator in my 2003 civic. I was able to get the existing one out without too much difficulty, however, putting it back in seems impossible. Refering the the 3rd illustration above, Part A on my car is rusted solid and there is no way to move the bolt with the nut and wingnut on it. I can get the belt back on the alternator but I cannot then move the alternator in place to bolt it. Is that because its already tensioned and without Part A working, I probably won't be able to get the alternator back on? If so, what is the Part A actually called or would you have a part number or something so that I can try to purchase one? Thanks for the help.



January, 2, 2012 AT 7:06 AM

Part A in the third drawing is the adjuster. You can probably get one at a junkyard. Or, you can use WD-40 to help break the rust loose.

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