Technical Description of OBD-II Trouble Code
Engine Coolant Temperature Input Not Present in Auto Configuration
What does that signify?
This is a generic diagnostic trouble code (DTC) that is applicable to many OBD-II vehicles (1996-newer), including Nissan, Toyota, Mazda, Hyundai, Kia, and others. Although it is a generic code, the specific repair steps may vary depending on the year, make, model, and powertrain configuration of the vehicle.
If your OBD-II equipped vehicle has stored a code P063F, it means that the powertrain control module (PCM) has not detected a signal for the auto configuration engine coolant temperature input.
When the ignition cylinder is turned to the ON position and the various on-board controllers (including the PCM) are powered, multiple self-tests are initiated. The PCM relies on input signals from engine sensors to automatically configure an engine start-up strategy and perform these self-tests. Engine coolant temperature is one of the crucial input signals required by the PCM for auto configuration.
The engine coolant temperature sensor (ECT) should provide the PCM (and other controllers) with an input signal for engine coolant temperature for automatic configuration purposes. The ECT is a sensor made of brass, steel, or plastic with a thermal resistor inside the tip, which is suspended in resin. The ECT is usually threaded into an engine coolant passage so that the tip is inserted into the passage. As engine coolant flows across the tip of the sensor, it affects the thermal resistor inside. As the engine coolant warms up, the resistance of the ECT sensor decreases and the circuit voltage increases. As the engine coolant temperature decreases, the resistance of the ECT sensor decreases and the circuit voltage decreases.
If the PCM fails to detect an ECT sensor input circuit when the ignition switch is turned to the ON position and the PCM is powered, a code P063F will be stored and a malfunction indicator lamp may illuminate. The auto configuration system may also be deactivated, resulting in serious drivability issues.
A typical coolant temperature sensor:
What is the severity of this DTC?
Auto configuration codes should be taken seriously as they can affect engine start-up idle quality and drivability. Classify a stored code P063F as severe and address it accordingly.
What are some of the symptoms of the code?
Symptoms of a P063F trouble code may include:
What are some of the common causes of the code?
Causes for this code may include:
What are some P063F troubleshooting steps?
If there are other ECT related codes present, diagnose and repair those before attempting to diagnose the P063F. Also, ensure that the engine has the appropriate coolant level and is not overheating before testing.
To accurately diagnose a code P063F, you will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), an infrared thermometer with a laser pointer, and a reliable source of vehicle information.
Refer to your source of vehicle information for applicable technical service bulletins (TSB). If you find one that matches the vehicle, symptoms, and codes you are dealing with, it may help in reaching a correct diagnosis.
I always start any code diagnosis by connecting the scanner to the vehicle diagnostic port and retrieving all stored codes and relevant freeze frame data. I prefer to write down this information (or print it if possible) in case I need it later after clearing the codes. Next, I clear the codes and test drive the vehicle until one of two scenarios occurs:
A. The code fails to reset and the PCM enters readiness mode
B. The code is reset
If scenario A occurs, you are dealing with an intermittent code and the conditions that caused it may need to worsen before an accurate diagnosis can be made.
If scenario B occurs, continue with the steps listed below.
Step 1
Perform a visual inspection of all related wiring and connectors. Check PCM power supply fuses and relays. Make any necessary repairs. If no problems are found, proceed to the next step.
Step 2
Obtain diagnostic flow charts, wiring diagrams, connector face views, connector pin-out charts, and component testing specifications/procedures from your vehicle information source.
Once you have the correct information, use the DVOM to test the ECT voltage, ground, and signal circuits.
Step 3
Start with a simple test of voltage (usually 5 volts) and ground signals at the ECT connector. If there is no voltage, use the DVOM to trace the circuit back to the appropriate terminal of the PCM connector. If there is no voltage on this pin, suspect that the PCM is defective. If there is voltage at the PCM connector pin, repair the open circuit between the PCM and the ECT. If there is no ground, trace the circuit back to the central ground location and make any necessary repairs. If ground and voltage are present at the ECT connector, proceed to the next step.
Step 4
Use the infrared thermometer to determine the actual temperature of the engine coolant. The scanner data stream will reveal what temperature (or degree of voltage) is being input to the PCM (if any). Compare the voltage to temperature information (found in your vehicle information source) to determine if the ECT sensor is functioning normally.
If the ECT and all system circuits are functional, suspect a defective PCM or a PCM programming error.
