Randy18

2004 base model 3.9
So anyway a couple of weeks ago I had a new alternator installed. When I picked it up the check engine light was o. Codes p0141, p0161. Mechanic did understand why. I drove for 350 miles and diconnected the battery. The light was off for 2 days but back again.

Anybody have a suggestion.
Thank for the assistance

cliffyk

P0141 and P0161 both indicate excessive current draw, or a short, from the heaters in the passenger (P0141) and driver's (P0161) rear O² sensors. The possible causes are the same as for P0135 (just different circuits).

The heaters for all four O² sensors are powered from the same source, fuse 2.8 (20A) in the central junction box, which also powers the EGR and both EVAP valves, so its being a blown fuse is unlikely--but check it anyway (download an owner's manual here should you not have one).

The heaters are switched on an off by the PCM as needed so it is most probably a wiring problem, though I do not know what about changing the generator could have caused such a problem. Inspect the wires at the rear sensors for physical damage. It is remotely possible that the PCM MOSFET switches used to control the sensors are blown out; changing out the generator without disconnecting the battery, especially if something "sparked" during the process could damage the PCM.

Again, this is quite unlikely. Check the fuse and examine the wiring to the rear sensors.

Randy18

thanks for the help!!

Randy18

over the weekend lets see how long it stays off this time.