P0597 - THERMOSTAT HEATER CONTROL CIRCUIT OPEN

The diagnostic code P0597 OBD2 has to do with a failure in the electronically controlled engine thermostat system. It indicates that the control voltage is non-existent. The thermostat has several load temperature sensors.

The function of the thermostat heater is to control the flow of coolant, in addition to regulating the operating temperature of the engine. The Engine Control Module (ECM) supplies 12 volts to the thermostat.

In case the ECM detects an incorrect signal from the thermostat, the DTC code P0597 OBD II is set.

• Illuminated Check Engine light.
• The temperature gauge may show an excessively high reading if the thermostat failed in the closed position, and low temperature if the thermostat failed in the open position.

DTC code P0597 OBDII means that one or more of the following problems has occurred:

• A thermostat connector may be corroded or loose.
• Possible leakage of refrigerant.
• The cables between the ECM and the thermostat may be defective.
• The thermostat may have failed.

For proper correction of fault code P0597 OBD2, you must do the following:

• Check the coolant level in the radiator. If the level is low, the electronic thermostat may have overheated.
• Remove the electrical connector from the thermostat and check its condition. If it has corrosion, you must remove it. When connecting it again, make sure it is tight.
• Check the thermostat resistance values. You should compare the results with a service manual. If they do not match, replace the thermostat.