The P0599 trouble code indicates that there is a high voltage condition detected in the thermostat heater control circuit. Modern engines use a thermostat to regulate engine temperature. The thermostat heater helps to warm up the thermostat quickly to allow the engine to reach operating temperature more efficiently. A high voltage condition in this circuit can cause the thermostat to overheat, potentially leading to engine performance issues and emissions problems.
P0599 Thermostat Heater Control Circuit High
Code symptoms P0599.
1. Engine may run hotter than usual.
2. Poor fuel economy.
3. Heater may not function properly.
4. Check Engine Light illuminated.
This code is common in brands such as:: Chevrolet, Renault, Ford, Toyota, Nissan, Mercedes Benz, Honda.
Causes of the code P0599.
1. Faulty thermostat heater.
2. High voltage in the thermostat heater control circuit.
3. Wiring or connector issues in the thermostat heater control circuit.
4. Corroded or damaged terminals in the thermostat heater control circuit connectors.
Code Solutions P0599.
1. Inspect the thermostat heater for any signs of damage or malfunction and replace if necessary.
2. Use a multimeter to check the voltage in the thermostat heater control circuit. If voltage is high, diagnose and repair any issues causing the high voltage condition.
3. Check the wiring and connectors in the thermostat heater control circuit for damage or corrosion. Repair or replace any damaged wiring or connectors.
4. Thoroughly inspect the terminals in the thermostat heater control circuit connectors for corrosion or damage. Clean or replace any affected terminals.