Topic: Code 41

[neale_rs]

My YJ is showing code 41, having to do with the alternator field.  The dash voltmeter shows it is charging and it hasn't shown any other symptoms.  However, I can't say I've looked at the voltmeter every time the check engine light has come on. 
 Could this be the start of the alternator going bad (it is about 15 years old)?

Thanks

[Jeffy]

Either the alternator or the PCM.  You can have the alternator checked easily enough.

[neale_rs]

I guess I'll start with that.  Thanks

[neale_rs]

I've been monitoring this fault and the YJ has gone through 9 drive cycles so far without the check engine light coming on (actually more, but 9 since I started monitoring).  It also always shows that it is charging on the dash voltmeter.  I've decided to leave it alone for now and worry about it only if it stops charging or if it starts to show the fault in 1 out of 4 drive cycles.  Right now it is too sporadic to be able to figure it out easily.

[Bikerjr1]

just a thought, I know intermittent electrical problems can drive you nuts.  you might clean all your mains off the alt and die-elect grease them.  you might also check the prongs on the relays and fuses on the main block.  alittle emery cloth goes a long way on intermittent faults. don't forget the grounds.
luck with it,
JR

[neale_rs]

Hopefully it is just something like that.  Thanks

[neale_rs]

Just an update:

The code started coming up almost every time the YJ was started.  After the last wheeling trip, the voltmeter starting showing it was not charging every so often.

Decided to get a new alternator (90 amp replacement vs 75 amp stock).  It seems to have solved the problem, has been started 9 times so far with no code 41.