[rodeo02]

I see from your profile this is in regards to a 2000 passport? right? I personally would not use AAMCO for anything. Way too may horror stories from that place, although I'm sure there's good ones out there. Generic definition of P1870 = "Transmission Component Slipping/ Transmission Mechanical Transfer Case 4x4 Switch Circuit Failure" It's possible isuzu/honda has slightly different wording for this OBDII code. What is the history of the unit? how many miles on it? have you done ATF changouts every 25-50000 miles? If you get absolutely no symptoms from it other that the CEL, I'd drive it ( & save for a new one)until it acts up, then replace it.
G/luck
Joel