OBD-II Trouble Codes

P00B6 Code: Radiator Coolant Temperature / Engine Coolant Temperature Correlation

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An on-board diagnostic or OBD-II code informs you of the possible issues your vehicle may have. To successfully resolve it, you must first know what the logged code means. One of the codes that you may retrieve from your scan tool is the code P00B6. Read on to learn more about its definition, possible triggers, and common symptoms.

What Does the P00B6 Code Mean?

Diagnostic trouble code (DTC) P00B6 stands for “Radiator Coolant Temperature/Engine Coolant Temperature Correlation.” This error code is logged when the powertrain control module (PCM) detects that the difference in signals between the radiator coolant temperature sensor and the engine coolant temperature (ECT) sensor is above factory specification.

radiator coolant
Code P00B6 is logged when the PCM detects that the difference in signals between the radiator coolant temperature sensor and the engine coolant temperature (ECT) sensor is above factory specification.

Some vehicles have two coolant temperature sensors: one in the engine and another in the radiator. The PCM uses the signals from these sensors to determine the temperature of the cooling system.

The internal resistance in the ECT sensor typically decreases as the coolant warms and flows through it. This action translates to a decreased ECT sensor circuit voltage sent to the PCM. Once the engine cools, the thermal resistance in the ECT increases. As a result, the ECT sensor circuit voltage in the PCM is increased. The PCM perceives these fluctuations in voltage as changes in engine coolant temperature.

However, if the PCM notes a discrepancy higher than the allowable threshold between the radiator coolant temperature sensor and the ECT sensor’s signals, it will log error code P00B6.

Note: The definition of code P00B6 may be different depending on the vehicle manufacturer. Consult the appropriate repair manual or repair database for the exact code definition.

coolant temperature sensor
Issues with the radiator coolant temperature sensor can cause P00B6 code.

What are the Possible Causes of the P00B6 Code?

P00B6 is a generic code, so it can have many causes. Here are the most common:

What are the Common Symptoms of the P00B6 Code?

You may notice the following symptoms if you own a vehicle with a logged P00B6 trouble code:

engine overheat
Engine overheating is a symptom of code P00B6.

How to Diagnose the P00B6 Code

Although P00B6 is a generic code with triggers and symptoms similar to other DTCs, there is no universal fix for this code. Vehicles are built by automakers differently, so the exact diagnostic and repair procedures may vary.

Repair steps for a logged P00B6 on a Chevy Cruze may not work for a P00B6 on a Range Rover. So, as a rule of thumb, always refer to a repair manual for the appropriate diagnostic steps.

How to Fix the P00B6 Code

Code P00B6 may be set in vehicles of varying makes and models. Refer to the factory repair information specific to your car before DIY-ing any repairs. If you aren’t confident in your auto repair skills, it may be best to leave the job to a professional.

However, if you’re set on resolving this code on your own, make sure your automotive knowledge is up to date before attempting any fixes. Refer to a repair manual or an online repair database to learn how to resolve code P00B6.

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