Question about 2009 Honda Accord LX
Alternator was bad, output 18v, changed it but now it's not charging system. Also has new battery.
Did you really check all fuses. (using an ohmmeter)
what engine, I4 or V6?????
are you posting to someone elses PCM Com problem or what?
is this just and alternator issue , how confusing can this be....
PCM> coms. fails.
1: pin 16 in the OBD2 conn, is not 12vdc. blown fuse. (use a voltmeter)
2: wrong scan tool old tool , on modern CAN buss car will fail. 100%
dead. (open SCAN tool book read if it supports CAN buss)
3: Dead PCM or id bet its , a fuse blown to it.
now i do ALT.
18v is bad. (using a quality DMM or radio shack 1960 meter?)
it means the ALT regulator OUT of CONTROL. ( or bad wiring to it)
changed what?, alt is new, used, rebuilt, barrowed? what.?
This car , im looking it up now, at alldata.com so could you,
or the FSM.
this ALT has a regulator, but is just a slave to the PCM.
in that the PCM controls the REG with 3 wires.
the diagnosis is not easy , i recommend, the FSM
it covers all steps., in the diagnosis,
top fail reasons.
1: bad fuses.
2: bad wiring and connections. (see schematic)
3: bad battery (not you) (open cells cause REG to shut down. )
4: bad ALT. (i say a fella change alt 5 times, and skipped #2)
5: bad PCM. (last, , show me that tests, in FSM)
all that and tons more in the FSM. read it.
or log in to alldata.com and read the Charging pages.
Posted on Jan 04, 2014
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Posted on Jan 02, 2017
if you have or can gain access to a voltmeter, while the car is running without jumper cables on it hook up the voltmeter to the batter posts and see what the alternator is charging at, a good working alt should charge from 13.5 to 15v, i have seen many new parts go bad fast or be bad from the start
Posted on Mar 12, 2010
There's a very good possibility the voltage regulator is bad, but it's on the alternator and usually the whole alternator is replaced when this happens..
Posted on Oct 26, 2010
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