Dodge Charger P2181: Symptoms, Causes and Diagnosis

 

P2181 indicates that your Dodge Charger has an observation cooling system temperature that is either too high or too low. It will appear in the scan tool as “Cooling System Performance.”

The problem with the P2181 is that by itself, it doesn’t make much of a difference. There could be a problem in your Charger’s cooling system, temperature sensor, or even the ECU.

P2181 Dodge Charger

Dodge Charger: P2181 Symptoms

  • Engine overheating
  • Engine too cold
  • Does not heat up or heats little
  • Stalls and rough idle

If the engine stalls and runs rough after getting this code, it is likely that the head gasket has blown if it has become hot. If the engine is running cold, it could run poorly because it is too rich.

P2181 Causes: Dodge Charger

When left alone (without other fault codes), there are many different problems that can cause P2181 on your Dodge Charger. How you look for them will depend on whether the temperature gauge shows too hot or too cold. We will discuss this in-depth in the Good Diagnostic Practices section below.

Defective temperature sensor

Dodge Charger P2181 Diagnostics

Since the temperature is “out of range”, very often it is the temperature-sending unit itself that is causing P2181. If your Charger is clearly overheating, the gauge should work fine, and you’ll need to focus on why your vehicle is overheating.

Always trust the pressure gauge until you can verify that it is really wrong. Never leave your Charger running while the pressure gauge shows that it is overheating.

Problems with the cooling system

  • Faulty thermostat– The thermostat controls the amount of coolant that enters your Charger’s engine. If left open, the engine may never fully warm up. If it is not opened at all, the engine will overheat FAST, usually within a few minutes of starting the engine.
  • Water Pump– If the water pump is not working properly, coolant will not be able to move through the engine and remove heat, which can cause overheating.
  • Defective radiator– A clogged radiator slows down the flow of coolant and causes overheating.
  • Low coolant– If the coolant level is low, there will not be enough to cool the vehicle. Refilling it will temporarily solve the problem if the leak is small, and will do nothing if the leak is large.

Defective ECM/PCM/ECU

P2181 Bad ECM

The engine computer has many names. No matter what you call it, computer problems are known to cause P2181.

P2181 Charger Diagnostic: Decision Tree

Before proceeding to diagnose P2181, make sure your Charger does not have any other diagnostic codes. Since this code has so many potential causes, other code can help you narrow it down considerably.

1. Check the coolant level

P2181 Causes: Dodge Charger

Be sure to check the coolant level before doing anything else. It is very possible that the coolant is empty if you receive the P2181 message.

If it is empty, you will have to add more coolant. Never add coolant to an overheated engine, as this can cause the cylinder head to crack. You will have to find the source of the leak. Start by looking under the vehicle and see if you can find any coolant drips. Follow the drip to the source. This may be more difficult than it seems.

If the coolant is full, it is time to check the temperature by sending the unit

2.Temperature Sending Unit Test

Since this code indicates that the perceived engine temperature is out of range, it would be best to first take a look at the Charger’s temperature sensor and make sure it is working properly.

You can go to point 3a⬇️ if your charger visibly overheats.

If the gauge reads low, try turning on the heater after the car has been running for a while. If the air coming out of the vents is not hot at all, that would be a good confirmation that the gauge is reading correctly. Go ahead and jump to 3b⬇️.

Here’s how to check if your sending unit has faulty wiring, and how to use a multimeter with hot/cold water to test the sensor (YouTube).

If the sending unit is bad, replace it and it should clear P2181. If not, let’s move on to step 2.

3. Does the gauge read too hot or too cold?

Okay, now we know that the temperature gauge is working correctly. Let’s continue diagnosing P2181 by determining if the engine is running too hot or too cold.

3a. Too hot

If the engine is too hot, go to step 4⬇️.

3b. Too cold

If your charger is running too cold, it is most likely the thermostat that is the culprit. Replacing the thermostat is usually a fairly simple repair.

4. Thermostat

Diagnosing a faulty thermostat
A typical thermostat

We know from step 1 that the engine is full of coolant. This leaves the radiator, water pump, or thermostat. Since the thermostat is the easiest to check, we’ll start there.

With the engine warm (but not overheated, turn it off before that happens) tighten the tube that goes to the water pump from the radiator. If it is lame, go to step 6, the water pump.

If the hose is difficult to tighten, we know there is solid water pressure. The thermostat may not open.

Does the heater work? If the thermostat is completely closed, it shouldn’t be. That would be enough proof that the thermostat is not opening. For more information, see the faulty thermostat diagnosis section of this site.

If the heating works well, let’s move on to step 5.

5. Radiator

There was good water pressure in the radiator hose, and the heater seemed to work fine. You’ll have to take a look at the radiator. Here’s how to diagnose a faulty radiator.(YouTube).

6. Water pump

Lastly, the water pump. If you’ve made it this far, it’s very likely that the water pump is the culprit. Have you heard any squeaking coming from the vehicle?

That’s a good sign that your Charger’s water pump is bad. Here is a good water pump diagnosis video. Here is a page on this site about diagnosing a bad water pump in your Charger.

7. NDE

If you’re looking at your Charger’s ECM, you probably haven’t found anything visibly wrong with the temperature-sending unit, and nothing seems wrong anywhere in the cooling system. It could be the ECM that is faulty, although it is not very likely

Before touching or considering the ECM/PCM, you should verify that the engine temperature is correct with a temperature gun and that the sending unit is working properly. At that point, you would need the PCM updated, which your dealer should be able to do for you.

Dodge Charger P2181 Conclusion

We hope this article has helped you diagnose p2181 on your Charger. It’s certainly not the easiest code to figure out.

 

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