Check engine light on?

Many things can set the check engine light. What you need to do is have the computer scanned to identify the trouble code. Most parts stores will do it for free.

Have that done and let me know what you find.

Joe

The Engine Computer detected a problem, set a diagnostic fault code, and turned the light on to tell you. The first thing to do is read that code. Many auto parts stores will do that for you for free, but you have to remember, they understand parts. They mostly never were mechanics. Fault codes never say to replace parts or that they're bad. They only indicate the circuit or system with the problem or the unacceptable operating condition.

Chrysler makes reading the engine codes yourself much easier than any other manufacturer. Cycle the ignition switch from "off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the code numbers show up in the odometer display. Holler back with those numbers.

P0138 - Left Bank Downstream or Downstream and Pre-Catalyst O2S Shorted to Voltage - Oxygen sensor input voltage maintained above the normal operating range

A P0301 code means that the the car's computer has detected that the #1 cylinder is missfiring it could be causing the P0138 code or the p0138 code could be causing this code, check your spark plugs wires, injectorand compression.

I belive P1682 is not a code for dodge manafacture.

P1682 Charging System Voltage Too Low

i looked at that one wrong sorry, check your alternator.

If the belt is slipping it wont turn the alternator properly. Check all I told you first the alternator will not cause those problems.

It's not just a coincidence that the rear o2 sensor and overdrive solenoid are on the same transmission subharness as the other sensors used as a vehicle speed reference by all the computers. While replacing your o2 sensor, be sure to check the grounds and wiring for all the other local information sensors. The vehicle speed sensor, the input and output sensors and the overdrive solenoid all are on the same body transmission sub-wiring harness.
If you need any help with identification or power, ground, or reference signal locations, just ask, or see the site's index or service manuals available by 2carpros. Com. I'm not going anywhere either. OK sir or Madam Just let me know if you need anything. I am a fan and technician for all the great Dakotas.

First, relax. If you have kept the oil changed and the engine hasn't been abused, a 3.9 is just getting broken in at 200K. What you need to do is this. When the check engine light is on, have the computer scanned at a parts store. Most do it for free. That will identify why the light is coming on. If the engine is running fine other than the light, chances are it is a sensor ir EVAP issue that doesn't even relate to the engine.

Now for the coolant coming through the heater, that is a different issue. You need a new heater core. Again, that has nothing to do with the engine. However, make sure to keep an eye on the coolant level. If it is leaking at the heater core, the level will go down and you don't want to overheat the engine.

A word of advice. I have owned Dakotas for the past 20 years. The lowest mileage one I sold had 225K on it and still ran great. I just wanted a newer one. And yes, they all had the 3.9L V6 engine. The only bad part about them are the earlier automatic transmissions had issues. If your trans is still solid, run it another 200K.

Joe

Don't replace the messenger. It's just telling you there's a problem. Start by measuring battery voltage with the engine running when the problem occurs. Normal is between 13.75 and 14.75 volts. If it is low, measure the voltage on the two small wires on the back of the alternator. They could be two plugged-in wires or two small nuts on the tabs coming out of a small black plastic block. There will only be voltage there while the engine is running. One will have full battery voltage on it. The starting point for any diagnosis is the second terminal, It must have less than battery voltage, but not 0 volts.

Caradiodoc

If the check engine light was on, have the computer scanned to identify trouble codes. Also, if it happens again, see if it will start with starting fluid. If it does, there is a fuel delivery problem. If it still won't start, chances are you lost spark to the plugs.

Possibilities: Inspect and test all the following listed below:
Oxygen sensor.
Catalytic converter.
Fuel injectors dirty/sticking.
Mass airflow sensor/Airflow meter.
Throttle position sensor.
Crankshaft position sensor
Knock sensor
Manifold absolute pressure sensor.
EGR Valve
Fuel pressure regulator leaking or defective fuel pump.
False air leakage.
Fuel contamination.
Foul/defective spark plugs.
Open spark plug wires.
Ignition coil/Coil packs defective.
Incorrect ignition timing.
Cap and rotor.

Note:If it doesn't apply disregard it.