x_orange90_x Posted October 15 Report Share Posted October 15 2017 Dodge Journey GT AWD 3.6L 110k Miles A couple days ago I was on my way home from my in law's house and while driving the Engine light came on. I was right about in the middle of my 25 minute drive, engine warmed up and running fine. I pulled the code when I got home. It was pending and so I left it to see if it would go back off but it has not. The temperature gauge is going to the normal range, the heat appears to work fine, and nothing else seems obviously wrong. I've been reading that there are several things that CAN cause this code, not most of the time it's the thermostat. I don't want to take guesses at it and start replacing random parts, so I figured the experts here could give me an idea based on their experiences. It was in the 40s I think at the time it came on, and being October here in Michigan it's getting colder now. I can't stand NOT having remote start 🥶 Quote Link to comment Share on other sites More sharing options...
larryl Posted October 15 Report Share Posted October 15 (edited) Sometimes the thermostat opens and the car doesn't warm up to proper temp. Mine has done it a few times but I just clear the code I don't mind it running a little cool and the remote start will work Edited October 15 by larryl Quote Link to comment Share on other sites More sharing options...
x_orange90_x Posted October 15 Author Report Share Posted October 15 1 hour ago, larryl said: Sometimes the thermostat opens and the car doesn't warm up to proper temp. Mine has done it a few times but I just clear the code I don't mind it running a little cool and the remote start will work I was thinking it might be a fluke. The coolant is at the bottom of the COLD range, so it is a little low but probably not enough to trip the sensor. Also, the fan DOES switch on and off with MAX A/C on, so that's working properly. I watched it warm up leaving work today and within 3 minutes it was at 110 and after about 15 minutes of driving it was around 210-215. I think I may just clear the code and see if it comes back. Quote Link to comment Share on other sites More sharing options...
Dean H Posted October 18 Report Share Posted October 18 P0128 Thermostat rationality. Theory of Operation- The Thermostat is considered malfunctioning if the coolant temperature does not reach the highest temperature required to enable other diagnostics, or the coolant temperature does not reach a warmed up temperature within 20°F of the Thermostat regulating temperature. The Powertrain Control Module (PCM) creates a model of the engine coolant temperature warm up cycle, based on the engine coolant temperature at start up, ambient temperature, vehicle speed and engine speed. The modeled engine coolant temperature is compared to the Engine Coolant Temperature Sensor reading. If the engine actual temperature reaches the calibrated temperature threshold before the model, the diagnostic passes and completes. If the model reaches the calibrated temperature threshold before the engine actual temperature, a pass/fail determination is made based on the difference between the model and actual values. The diagnostic is considered passing if the difference between the engine actual temperature and model is acceptable when the model is greater than the engine but represents the slowest possible warm-up for a "good" thermostat. When Monitored and Set Conditions When Monitored: This diagnostic runs when the following conditions are met With the engine running. Start up coolant temperature less than 65 deg * C (149 deg * F) Ambient temperature between - B deg * C (17.6 deg * F) and 50 deg * C (122 deg * F) Average vehicle speed greater than (10 coolant temperature reaches 85 deg * C Engine speed does not go above 5400 rpm for more than 32 seconds The pass/fail determination point is reached when the coolant temp model reaches 88 deg * C 190 4°F) Set Conditions: The predicted coolant temperature reaches the target threshold before the actual coolant temperature and the PCM detects that the actual engine coolant temperature is too far below the what is acceptable for a good thermostat Default Actions: MIL. light will illuminate Possible Causes --- LOW COOLANT LEVEL --- COOLING SYSTEM ISSUES --- THERMOSTAT OPERATION Quote Link to comment Share on other sites More sharing options...
Dean H Posted October 18 Report Share Posted October 18 (edited) Remote Start Operating Conditions. In order to operate remote start, the following conditions must be met- Key fob sequence must be operated within a 100 meter range of the vehicle. The vehicle must be in Park Fobik is not in the vehicle The hazard switch off Vehicle Theft Alarm or Panic is not alarming Doors and hood must be closed. The battery voltage is normal (11 to 15 volts). --Remote Start Shut Down/Deactivate Conditions--- Engine will NOT start or will shut down/deactivate during any of the following conditions below. Doors or hood are opened before remote unlock Hazard Switch depressed Panic or theft alam active Brake applied. If the vehicle is remote started and the customer then unlocks and enters the vehicle, the brake application will not stall the vehicle If the vehicle is remote started and no entry is detected, brake application will shut down the engine Low fuel levels, Fuel indicator active A prior remote start cranked the engine, but failed to start the engine. Battery voltage NOT in the normal range. High (run away) or Low Idle (stall) RPM. MIL Active. High Engine Coolant Temperature. Low Engine Oil Pressure. Edited October 18 by Dean H Quote Link to comment Share on other sites More sharing options...
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