did you push the reset button on the scan tool first then drive?or are doing the very hard, DRIVE till it clears, good luck there.which engine? see end for choicesshort Answer:got a vacuum leak.Long answer:no other codes? why change the 02? front one is Air/fuel 02.not rear.the ECU is telling you VACUUM leak, and lean.you failed to say what sensor you changed,? nor engine in car.all cars have at least 2 OXY sensors, 02.limp mode, is set, any time major sensors fail.on a race car with pro EFI system a major sensor failsand engine dies, no limp-in mode.on this production car, it has limp-in allowing the driverdrive car but at reduced power, (not getting stranded can save your life, no?)so that is what it is,and lean to that a code is not telling you to replace apartthe code is for you technician to do the tests stated in the bookto find true cause, can be, false code, bad wires, bad connectors and sure the sensors. you shot gunned it and now get to learn how to do this correctlymaybe?to understand codes, read the real jeep book , not web rumors of off some FORD. or chebby.0171 (old federal code for. fueling is LEAN.2173 (this is jeep factory code, only P2 = factoryand means.i think this is the mK49 jeep, a Mitsubishi GS based jeep.not really a jeep, makes finding accurate data for me harder.===================qoutes from FSM)================here is 2173 verbatumP2173-High Airflow/Vacuum Leak Detected (Slow Accumulation)P2173-HIGH AIRFLOW/VACUUM LEAK DETECTED (SLOW ACCUMULATION) For a complete wiring diagram, refer to the Wiring Information. When Monitored: Ignition on and engine running with no MAP Sensor DTCs.Set Condition:A large vacuum leak has been detected or the signal voltage for both TP Sensors is stuck at 2.5 Volts and calculated MAP is less than the Gas Flow Adaptation value. (comment note the TP angles and MAP DO NOT AGREE !!!!!) One trip fault; the DTC will set within five seconds. ETC light will flash.Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to DTC-Based Diagnostics/MODULE, Powertrain Control (PCM) - Standard Procedure) Diagnostic Test ACTIVE DTC NOTE Diagnose and repair any ETC, MAP Sensor, VSS, or 5-Volt supply circuit DTCs before continuing. Start the engine and allow it to reach normal operating temperature.===================end qoutes====================so what would you do.?you would find out why the map sensor reads wrongand why there is this huge vacuum air leak.this is EFI basics. if the MAP and my hand vacuum gauge agrees?then the MAP is not telling lies(clogged)so it's a real vacuum leak , I bet it is...google finding engine vacuum leaksor youtube that.hoses fell off , is #1 on a 2014 car, new.seems like STEP ONE.The 02 is not bad, the PCM told you this.MAP sees huge vacuum leak and engine runs lean.------------------speed density 101 EFi-------what is a MAP?its a baro sensorwhat is a baro, it measures, (vacuum)in science a barometer, measures, (here) absolute pressure,with engine off, the baro reads14.7 psi, (that is the air pressure at sea level)or as they say in europe 1 bar.the engine starts and engine vacuum is about 20"HGvacuumthe EFI takes the MAP sensor readingsthen using tables converts this to air flow in to engine then computes, that to fuel injection ratesthis is how all jeeps run. its MAP based system. on most or all jeeps(usa, no idea how a tigershark fiat engine runs in europe jeeps)when the map is dead, or if the leak is so bad that the EFI thinks(sic) its bad, or can't believe it?the ECU goes to limphome modethis is so the engine does not go hyper LEANand burn up engine head valves and fiendsit's protect your engine. let. it.THE ECU IS TAD SMARTER here.smarter that the average bear.?it sees throttle angles radically different than the map and know for sure, THAT IS NOT RIGHT.and drops to LIMP.this tells you all you need to know,..on topicbesides, push scan tool reset. drive see if the problem is cured.which engine
