View Full Version : 91 ECU in 92 R/T

10-21-2007, 08:02 PM
I got a 91 ECU from 89daytonashelby (thanks!) so I re-wired the 92 ECU connector according to the instructions in this thread:

Once I got the engine started (took 10 minutes to get it to fire which could be because it sat for almost a month), I got a code 41.

The FSM says: Alternator Field not switching properly. An open or shorted condition detected in the alternator field control circuit.

I moved the wire from pin 57 to pin 8 like the instructions say. I even checked for continuity between pin 57 and the dark green/orange wire on the ASD relay which checked out ok. I dont have a 91 FSM yet to compare schematics so I'm relying solely on the schematics posted in the thread posted above.

The alternator is charging fine. I get 13.8V charge system goal and 13.7V at the battery. I just get this code 41. I have a powertrain diagnostics manual but it's for a 93. So it's no help.

Any ideas?