Hello all,

I replaced the alternator on my 98 XK8 this week after it failed and required a ride home. First did all the checks I could find here. Thanx to all who have posted on the diagnostics and to Flakester's write-up on removal and installation which can be found in the Stickies.
When it was delivered, it had been recharged to drive onto the flatbed, and it started right up to drive it off. Battery 12.40v, front fuse box 12.38, ECM 12.38. No increase when running with lights, fans, rear defrost, etc. Loud whine from alternator (confirmed with stethoscope). No corrosion or loose connections found, no ground failures, and no drop in voltage overnight on battery less than six months old, so I ordered the alternator from Rock (Pure Energy, remanufactured).

Details of failure: Drove 50 daytime highway miles with voltage on dash meter dropping, ending with beeping, dash lights flashing, and gauges cycling. My son, whom we were meeting for dinner, came with a jump starter/charger and we drove a mile or so without incident to the restaurant where we had reservations to celebrate his and his son's birthdays. After dinner, it was dark and late, so we drove to their home, nearby, and decided to leave it overnight. He drove us home, and I would return the next day with tools and testers to sort it out. Next morning, I loaded my winter X type with the equipment and went to return library materials in town about 4 miles away before heading to his house. 'Double Whammy', as I left the library the shifting was irregular and then began to slip without warning. I had changed the fluids in the transmission, transfer case and differential last summer when I was prepping it for winter with new plugs, coils and battery. "Must be a transmission leak," I thought, and headed back home in second gear, the only one working. Checking the transmission and transfer case, I found nothing amiss, levels were good. I was now without a car in the middle of nowhere (that's where I live). I called a couple of towing companies, one near me and one in the city where my son lives; by now it was snowing hard, and I knew they would be busy. The local one didn't respond to my call or message, but the other one said they could pick it up in an hour. Unfortunately, my son was working in another city 25 miles away, the car was inaccessible to a truck, would probably need a charge to be driven to the street and he had the keys. I gave them the addresses, they gave me the cost, and my son would call them in the morning for pick-up.

Now for my question. After installation and testing of the alternator, I scanned (Autel Maxicheck) for DTC's left from the dead battery and found only the one in the title above. I was unable to find anything further here or in an internet search. I did, however find a different explanation of the code in Rev. Sam's list in the stickies indicating a battery problem. Does anyone have experience with this code? If it is, indeed, the latter, perhaps I can erase it and see if it returns?
I would sincerely appreciate any help offered.

Best, Rick

 

Here's the excerpt from the 5HP DTC list:



Clear it and see if it recurs.

 

Thanx Mike
Best, Rick

 

After erasure, we went grocery shopping (30 miles round trip). Turned on all electrics and kept an eye on the voltmeter for the first road test of the alternator. Behaved as expected. Back home, no codes of any kind. Unfortunately, I still have the X type to deal with and Winter at the doorstep.

Thanx again Mike for the quick response.

Rick

 

Funnily enough we were talking about the Goldilocks zone in another thread. It looks like you have found the Goldilocks zone for just the right range of low voltage to trigger an error. Presumably they think that less than 7V the car wouldn't start at all.

 

When it shut down nothing electrical worked: no interior lights, no dash lights, had to over-ride the gear lock to push it out of the way, use key to open trunk. When we hooked up my son's jumper pack, it measured battery voltage as 0v.

Best, Rick