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 computer has detected a problem with the thermostat heater. It's like a small electric heater that helps the car's engine stay at the right temperature. If this heater isn't working, the engine might not get warm enough.
The P0597 code indicates that the engine control module (ECM) has detected an open circuit in the thermostat heater control circuit. This means that the electrical connection to the thermostat heater is broken or not working properly.
The thermostat heater is part of the engine's cooling system. It helps regulate the engine's temperature by opening and closing the thermostat based on the engine's needs. An open circuit in this system means that the ECM cannot control the thermostat heater, which can lead to improper engine temperature regulation.
• Check Engine Light illuminated
• Engine takes longer to warm up
• Poor fuel economy
• Faulty thermostat heater
• Damaged wiring or connectors
• Blown fuse in the thermostat heater circuit
ECM: Engine Control Module
OBD-II: On-Board Diagnostics, Second Generation
• Use an OBD-II scanner to confirm the P0597 code.
• Inspect the thermostat heater and its wiring for damage.
• Check the fuse for the thermostat heater circuit.
• Replace the faulty thermostat heater.
• Repair or replace damaged wiring or connectors.
• Replace the blown fuse.
• OBD-II scanner
• Multimeter
• Basic hand tools
$100 - $300
Moderate
• Chevrolet Cruze
• BMW 3 Series
• Volkswagen Jetta
• Regularly inspect electrical connections.
• Ensure coolant system maintenance is up to date.
• Replace thermostat at recommended intervals.
Sensor Issue
• Have the vehicle inspected by a professional if unsure.
• Avoid long drives until the issue is resolved to prevent engine damage.
Check if the vehicle's powertrain warranty covers thermostat components.
This code has been more prevalent in vehicles with electronic thermostat controls as manufacturers move towards more electronically controlled systems.
Moderate – While the vehicle might still be drivable, improper engine temperature can lead to increased wear and reduced efficiency.
Driving with an unresolved thermostat issue can lead to engine overheating or underheating, which may cause further damage.
• Engine at operating temperature
• Vehicle stationary with ignition on
The thermostat heater is typically located near the engine's thermostat housing, which is connected to the engine's coolant system.
Q: Can I drive with a P0597 code?
A: It's possible to drive, but it's not recommended for long distances as it may lead to engine temperature issues.
Q: How do I reset the P0597 code?
A: After repairing the issue, you can use an OBD-II scanner to clear the code. If not repaired, the code will likely return.
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Universal · Digital multimeter
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Universal · Wire connectors and repair kit
Useful when diagnosis points toward damaged wiring, corroded terminals, or connector repairs.
Useful if diagnosis points toward damaged connectors, wiring, or terminal repairs.
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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.