1993 XJ MIL Code "41"

Howdy...

I've got a 1993 XJ 4.0L with 248K miles. It still runs strong, but recently the engine warning light has been coming on. Not consistently, but once in a while. It often turns off at restart. Also, I notice that the (stock) voltmeter runs low (about 6-10V) for a while after startup (about 10-20 secs), then increases to normal charge indication level. The charge has been working as usual otherwise.

I checked the MIL code and got a "41", which is listed in Chilton's as "Charging system circuit - output driver stage for generator field does not respond properly to the voltage regulator control signal".

I read this as as a bad voltage regulator or maybe something in the alternator. With so many miles, it may be time for a new one. Otherwise, the engine runs about as smooth as expected for it's age.

But,

I was wondering if there is anything else I should check before sinking the money for a new one. What other checks should I do before concluding that it's the alternator? Could it be anything else?

Any help would be appreciated. I'm normally not cheap (this is my 8th Jeep ad I've treated them all first class, and have had my loyalty rewarded!), but with so many miles, it may be best to check out all of the possibilities.

Thanks!

-Steve

Both AutoZone and Advance Auto will test your alternator for free. You'll have to remove it from the vehicle, which is a OITA and requires a bit of contortion, but then you know you're testing the unit and not the rest of the circuits in the truck.