ABS Light coming on above 1,000rpms

[need4pwr]

Hi,
I did a search and had no luck. I have been trying to figure out this ABS light issue. The ABS light comes on above 1,000 rpms and goes off below 1,000 rpms (and/or when I hit the brakes). When I slam hard on the brakes, i do feel the ABS pulsating which leads me to believe the system is working. Heres the kicker, when I keep the car in drive and keep my foot on the brakes, the dash board lights dim and so do the headlights. Checked the voltage at the battery (approx 15-17 volts while the car is on; 15 volts at 800rpms and about 17 volts at high RPMS, 13.5 volts while the car is off). Everytime I rev the engine, the lights brighten up. I did see twice before the E-brake & battery light come on. Alternator and battery was replaced less than a year ago.

John
2001 Infiniti G20t

[lowproki]

Hey man u are having my same problem I changed battery and alternator and still does the same thing and when press the brakes lots of times does your car seem to wanna die

[need4pwr]

I don't beleive its at that point yet, but the lights do dim and the RMP's come down to about 500 or below.

[J..M]

Sounds like a earthing issue to me

[thefultonhow]

15-17 volts is waaaay too high. It should be around 14 volts with the car running and 12 volts with it off. It sounds like either a grounding issue like J..M suggested, or the voltage regulator in the alternator is bad.

[need4pwr]

how could I diagnose a short or ground?

[J..M]

A short usually causes the fuse to blow

Bad earthing makes weired shit occur when ya turn summink on

[lowproki]

But in my car i have lots of earth grouning running from the batterry to the body and engine

[J..M]

Right :zoinks:

[need4pwr]

Just checked all the fuses....all OK. Checked the voltage again tonight, 19.2 volts with car running at idle (no lights, no fans, nothing on). Are there any other fuses besides under the dash? I see the relays in the engine bay (on the passenger side), how do I check to see if they are good?

John

[thefultonhow]

My diagnosis is still the voltage regulator in the alternator. 19.2 volts is waaaaaay too high.

[need4pwr]

Taking it back to the guy who did the alternator...having him look at it today. Will keep you posted. Do you think the high voltage would kick on the ABS light?

[J..M]

Replace the alternator & while you at it replace the battery too, its been boiled to fuck with all that goin thro' it....... Jeyzers

[thefultonhow]

Low voltage can trip the ABS light (when my belt was slipping, I was getting it flickering), so I wouldn't be surprised if high voltage would do it too.

[J..M]

Its a 12v system ....... prolly just about ok from 10.5/11.0 to 14.0/15.0 ......... But 19.0 20.0 is going waaaaaaaaaaaaaaaaaaay too far ........... Fire extinguisher anyone ?

[davemac]

I can confirm that a P10 will store a "low voltage" code in the ABS computer that sometimes indicates you have a bad alternator. There is no high voltage code, but I would agree 19+VDC is too high and might show with an ABS light.

[need4pwr]

yeap...voltage regulator is shot....I replaced the alternator on 8/3/06 and it has a (1) year warranty. They are warrantying the alternator, but not the labor. $120 to replace it.

Guy is telling me that the alternators on the g20/sentras don't hold up well...is that true? First one lasted me 5 years.

Thank you for your help so far! I will let you know if this takes care of the light. He should have it done by days-end today, if not tomorrow.

[stamar]

You can do a non scientific search in this forum for alternator problems and it would back up that the g20 alternators do not hold up well.

[davemac]

Hmmm I guess I'm lucky. Mine is still original. At one time the top rad hose even leaked on my alternator. I probably jinxed myself now. Oh well.

[thefultonhow]

I'm pretty sure mine is original too.

[need4pwr]

Yeap...alternator replaced, voltage at 14.4 with the car on and the light is gone. Go figure!

Again. Thank you for all your help!

[AzG20P11]

wow, its taken me a couple months of periodic searches to come across my exact problem, but here it is thank god

im glad it ended up being the voltage regulator, because i just blindly bought a new nissan alternator after fighting with this wierd problem for months on end