Hello, I’ve been having the same code on my 2002 ranger 3.0 for a few months now. It’s throwing the P0112 IAT Sensor 1 Circuit Low Bank 1. I have already replaced MAF as well as the connector. I replaced the wire going from the connector directly to the PCM to eliminate an open wire grounding out. When I read what the temper sensor is sending it reads 300 degrees F. If I disconnect the wire it drops down the -40 degrees F. The only other thing I could think of would be to replace the PCM but I would like to see if anyone else has any advice/experience with this problem. Thank you!

 

Yes, 2002 Ranger should have 6 wire MAF which means the ACT(IAT) sensor is inside it

The two outside wires are for the ACT(air temp) sensor, should be a grey/red and then a grey wire
grey/red wire runs to most sensor, its a shared signal return wire
grey wire runs back to PCM sensor return wire

Its a 5volt sensor like the other sensors, very similiar to ECT sensor in it temp reading/voltage

Unplug MAF and test grey/red wire, key on
Then unplug ECT sensor and test its grey/red wire or TPS it has shared grey/red wire as well
With key on engine off they should all show the same voltage

Could be some corrosion on the grey/red wire splice that's causing lower voltage at the MAF's grey/red wire but not on the ECT or TPS