Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
The car's computer thinks the engine's temperature is too low because it got a weird reading from a sensor that checks how hot or cold the engine is.
The engine control module (ECM) is receiving a signal from the engine coolant temperature sensor that indicates the temperature is lower than expected.
The P1DEC code is triggered when the ECM detects a signal from the engine coolant temperature sensor that is out of the normal range, specifically indicating a lower temperature than what is expected for the engine's operating conditions. This could be due to a faulty sensor, wiring issues, or other related problems.
• Check Engine Light is on
• Poor fuel economy
• Engine runs rough or stalls
• Faulty engine coolant temperature sensor
• Wiring issues such as shorts or open circuits
• Faulty ECM
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the code
• Inspect the engine coolant temperature sensor and its wiring
• Test the sensor's resistance and compare to specifications
• Replace the engine coolant temperature sensor
• Repair or replace damaged wiring
• Reprogram or replace the ECM if necessary
• OBD-II scanner
• Multimeter
• Wrench set
$100 - $300
Moderate
• Toyota Camry
• Honda Accord
• Ford F-150
• Regularly check and maintain coolant levels
• Inspect wiring for wear and tear
• Schedule regular maintenance checks
Sensor Issue
• Avoid driving long distances until the issue is fixed
• Monitor engine temperature gauge closely
Check with manufacturer for specific warranty coverage on emissions-related components.
This code has been observed in vehicles with aging sensors or poor maintenance history.
Moderate – Should be addressed soon to prevent engine performance issues.
Driving with a faulty engine coolant temperature sensor can lead to engine overheating and potential damage.
• Engine at operating temperature
• Vehicle stationary
The engine coolant temperature sensor is typically located near the thermostat housing or on the cylinder head.
Q: Can I drive with a P1DEC code?
A: It's not recommended to drive for long periods with this code, as it can lead to engine performance issues.
Q: How can I reset the P1DEC code?
A: The code can be reset with an OBD-II scanner after the issue has been fixed.
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Fitment Required · Vehicle-fitment part
Relevant when coolant-temperature and warm-up faults indicate a thermostat-related issue.
Coolant-temperature and warm-up faults often lead to thermostat testing and replacement.
Thermostats are vehicle-specific and should be matched by engine and housing style.
View options on AmazonThese parts may be related to this fault category, but a code by itself does not confirm exact fitment or guarantee that replacing a part will solve the problem.