P0597

Symptoms

• Check Engine light is on
• Extended engine warm-up time
• Increased fuel consumption
• The engine runs at a reduced operating temperature
• Poor performance of the interior heater

Causes

• Broken wire in the thermostat heater circuit
• Oxidation or poor contact in the thermostat connector
• Faulty thermostat heating element
• Damaged ECU connector
• ECU malfunction (rare)

How to Fix

1. Read all error codes and document additional codes
2. Inspect the thermostat connector and wiring for damage, corrosion, or breaks.
3. Measure the supply voltage at the thermostat connector with the ignition on
4. Check the resistance of the thermostat heating element (compare with specification)
5. Check the integrity of the control circuit from the computer to the thermostat
6. Replace the thermostat if a heater malfunction is detected
7. Reset codes and test drive to check

Related codes

Error P0597 by Vehicle Brand