Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that the car's engine isn't getting warm enough. It's like when you try to take a bath, but the water is too cold.
The engine's coolant temperature is not reaching the expected level, which can affect engine performance and emissions.
The P112B code indicates that the engine control module (ECM) has detected that the engine coolant temperature is below the threshold required for optimal engine operation. This can be due to a thermostat stuck open, a faulty temperature sensor, or other cooling system issues.
• Check Engine Light is on
• Poor fuel economy
• Heater not working properly
• Faulty thermostat stuck open
• Defective engine coolant temperature sensor
• Low coolant level
ECM: Engine Control Module
Coolant: A fluid that absorbs heat from the engine and dissipates it through the radiator.
• Check the coolant level and top off if necessary.
• Inspect the thermostat for proper operation.
• Test the engine coolant temperature sensor for accuracy.
• Replace the thermostat if it is stuck open.
• Repair or replace the engine coolant temperature sensor.
• Refill and bleed the cooling system to ensure proper coolant level.
• OBD-II scanner
• Multimeter
• Wrench set
$150 - $300
Moderate
• Toyota Camry
• Ford Focus
• Honda Accord
• Regularly check and maintain coolant levels.
• Replace the thermostat at recommended intervals.
• Ensure the cooling system is free of leaks.
Engine Performance
• Avoid driving the vehicle for long periods until the issue is resolved.
• Monitor the temperature gauge for abnormal readings.
Check with your vehicle manufacturer; cooling system components may be covered under powertrain warranty.
This code has been associated with thermostat failures in certain vehicle models, particularly in colder climates.
Moderate – While not immediately dangerous, prolonged operation with this issue can lead to engine performance problems and increased emissions.
Driving with a malfunctioning cooling system can lead to engine damage. It is advised to address this issue promptly.
• Engine at operating temperature
• Vehicle in park or neutral
The engine coolant temperature sensor is typically located near the thermostat housing on the engine block.
Q: Can I drive with a P112B code?
A: It's not recommended to drive for long periods with this code, as it can lead to engine performance issues.
Q: How do I know if my thermostat is stuck open?
A: If the engine takes a long time to warm up or the heater is not working well, the thermostat might be stuck open.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Chassis and ABS faults usually need a scanner that can read brake-system data directly.
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Universal · Torque wrench
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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.