Hi guys. 1993 Cherokee Sport, 282k. Was sitting for 1 week. Started it and ran it today, CEL came on. It has been running great for years. Ran some errands and got it up to temp, shut it down and ran the CEL check. Get codes 12 and 42.

12 is Batt Disconnected. I did replace the battery about 2 months ago, but never got a CEL or anything.

42 is Auto Shutdown Relay. No idea where this is, but I'm gussing the 2 codes are related.

Seems to run fine as is. Any ideas?

 

The ASD relay is in the underhood PDC. If the ASD relay failed you could lose power to the fuel pump, or the relay is stuck in the "on" position.

 

I'm with Bustedback on this one.

Start by swapping in a new ASD relay in the power distribution center. The black box under the hood on the passenger side. Always good to have a spare relay on hand in the parts box anyways; money well spent; they aren't that expensive.

Then clear codes and see if any codes or symptoms return.

P.S. the code 12 is just informational and is usually related to the battery being disconnected recently; don't worry about that code.

Good luck!

 

Thanks TJ. I'm picking up a relay tomorrow at Autozone for $15. Is the process for clearing the codes to disconnect the batt and touch the cables together for 10 seconds?

 

UPDATE: Replaced the ASD and now it shows codes 12 and 41. I understand that 12 is no issue, but 41 is Alternator Field Switch. Any help with this last one would be appreciated...

 

A code 41 is almost always a failing alternator. 98.76345563% of the time anyways....