P0598: Thermostat Heater Control Circuit Low

What does P0598 mean?

P0598 is a diagnostic trouble code indicating "Thermostat Heater Control Circuit Low". The ECU is detecting a voltage reading that is below the expected range in the cooling system circuit. This typically points to a wiring short, a faulty sensor, or a grounding issue.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Engine overheating
• Temperature gauge reading high
• Heater not working properly
• Intermittent warning lights

Common causes

• Damaged or corroded wiring harness
• Loose or disconnected electrical connector
• Failed cooling system sensor or actuator
• Blown fuse in the related circuit
• Poor ground connection

What should you do?

Schedule a diagnostic appointment at your earliest convenience. The vehicle is generally safe to drive short distances, but the underlying issue should be addressed to prevent it from worsening.