If you have a Dodge with a P2181 OBDII code, there is a problem with the coolant temperature.
The onboard computer (ECM/PCM) is seeing a temperature out of range problem with the engine.
What is a Dodge P2181 OBDII Code?
A P2181 OBDII code is a “Cooling System Performance ” error.
When the onboard computer (ECM) detects the coolant temperature is too hot or cold and outside the correct range, it will give a P2181 trouble code.
Several components work together to keep an engine cool, with each needing to be checked for failure.
While a P2181 OBDII code is mainly caused by overheating it can also be caused by staying too cold.
8 Causes and Fixes for P2181 Code Dodge
- Engine Coolant Temperature Sensor
- Radiator Coolant Temperature Sensor
- Engine Coolant Low
- Thermostat
- Water Pump
- Radiator Fan
- Clogged Radiator
- Head Gasket
The engine coolant temperature sensor (ECT) is the sensor that reports the engine temperature to the onboard computer (ECM).
If it goes bad or has a bad connection, it will cause a P2181 error code.
The sensors can be tested to see if they are good or bad with a multimeter or simply replaced as a low-cost item.
The voltage can also be tested at the wiring harness to see if there is an open in a wire.
Some Dodges, mainly newer models, also have a radiator coolant temperature sensor.
It monitors the temperature inside the radiator, and if it goes bad can cause issues.
Most older Dodges will not have this sensor, while newer Dodge cars and trucks often will have it.
If the coolant level is low, the engine will overheat and cause a problem.
Check the fluid levels and be sure it is at the correct level needed.
The thermostat regulates the coolant temperature by mechanically opening and shutting as needed.
When the vehicle is cold, it stays shut, allowing the engine to warm up faster.
As the engine heats up, the thermostat slowly opens, allowing fluid to pass and begin to be cooled by the radiator.
When the thermostat fails and becomes stuck closed, the engine will heat up and not cool properly.
A water pump keeps water flowing through an engine and radiator, which cools the engine.
When the pump fails, the vehicle will overheat quickly and cause a P2181 trouble code.
Water pumps will often leak when they go bad with a small drip at the bottom of the unit.
The radiator fan blows air through the radiator cooling the coolant as it flows inside.
When there is no airflow, the car or truck will start to overheat when stopped or move slowly.
If the vehicle stays cool when driving over 20-30 MPH but overheat when stopped, the radiator fan is likely failing.
A radiator can become clogged up with age and need to be flushed.
When a radiator is clogged, it can cause overheating.
There are flush kits that can be bought to help flush out any debris inside.
In some cases, the radiator may need to be replaced.
In some rare cases, a bad head gasket can cause overheating and a P2181 OBDII error code.
While not common, it is something to keep in mind for a hard to troubleshooting vehicle that keeps overheating.
Summary
A Dodge with a P2181 OBDII code is having a problem with being too hot or too cold.
If the vehicle is not overheating, it is likely a bad sensor.
The engine coolant sensor is the most common failure, and it usually simply needs to be replaced.
On newer Dodges, there may also be a radiator coolant sensor that should be checked.
The onboard computer PCM on newer vehicles often compares the temperature between the two sensors and, when it is out of range, gives the P2181 error.
Older vehicles often only use the engine coolant sensor for information.
Low coolant levels can also cause problems so be sure to check the coolant level
A bad thermostat that regulates the coolant temperature may also have failed and should be tested or replaced.
The radiator fan and water pump can also cause overheating problems if they go bad.
If the radiator is clogged with debris, it can be flushed or replaced.
Have you had issues with a P2181 OBDII code in a Dodge? Let us know your thoughts below.