AutoCodes – GMC – P0598 GMC

P0598 GMC Code - Thermostat Heater Control Circuit Low

Quick Answer

The Engine Control Module (ECM) controls the Pulse Width Modulated (PWM) thermostat. Common causes include Failed Engine Cooling Thermostat Heater, Engine Cooling Thermostat Heater harness is open or shorted, Engine Cooling Thermostat Heater circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means: P0598 GMC indicates Thermostat Heater Control Circuit Low.
Common causes: Common causes include Failed Engine Cooling Thermostat Heater, Engine Cooling Thermostat Heater harness is open or shorted, Engine Cooling Thermostat Heater circuit poor electrical connection.
Severity: High - diagnose this code as soon as possible.
Can I drive?: Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

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Code Popularity 1,873

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 27, 2024

Description
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0598 GMC Description

The Engine Control Module (ECM) controls the Pulse Width Modulated (PWM) thermostat. The engine coolant thermostat heater controls coolant flow and regulates the engine operating temperature. The ECM supplies 12 V to the thermostat. The ECM controls the engine coolant thermostat heater by grounding the control circuit with a solid-state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage. The Diagnostic Trouble Code (DTC) will be set when the ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for greater than 15 s.

OBDII Code P0598 GMC - Thermostat Heater Control Circuit Low - AutoCodes.com — P0598 GMC Code - Thermostat Heater Control Circuit Low

What does this mean?

What are the Possible Causes of the DTC P0598 GMC?

Failed Engine Cooling Thermostat Heater
Engine Cooling Thermostat Heater harness is open or shorted
Engine Cooling Thermostat Heater circuit poor electrical connection

How to Fix the DTC P0598 GMC?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What does this mean?

Code Tech Notes

The engine coolant thermostat heater has a mechanical fail-safe in case of an electrical condition with the engine coolant thermostat heater. The mechanical thermostat will open at approximately 104Â°C (220Â°F). The mechanical thermostat will cycle from approximately 104Â°C (220Â°F) to approximately 98Â°C (208Â°F). The heater is part of the thermostat. The engine coolant thermostat heater and the thermostat housing are serviced as an assembly.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0598 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0598 GMC Code

1. What are the common symptoms of OBDII code P0598 in a GMC vehicle?

- Common symptoms include engine overheating, decreased fuel efficiency, and the vehicle's temperature gauge showing lower than normal temperatures.

2. What can cause the OBDII code P0598 (Thermostat Heater Control Circuit Low) in a GMC?

- The code P0598 can be caused by a faulty thermostat heater control circuit, a malfunctioning thermostat, wiring issues, or a defective engine control module (ECM).

3. How serious is the OBDII code P0598 in a GMC vehicle?

- The code P0598 should be addressed promptly as it can lead to engine overheating, which may cause serious damage to the engine if left unresolved.

4. Can I continue driving my GMC with the OBDII code P0598?

- It is not recommended to continue driving with the code P0598 present, as it can result in overheating and potential engine damage. It's best to address the issue as soon as possible.

5. How can I diagnose the OBDII code P0598 in my GMC?

- Diagnosing the code P0598 typically involves using an OBDII scanner to retrieve the code, checking the thermostat heater control circuit for continuity, inspecting wiring for damage, and testing the thermostat's functionality.

6. What are some DIY repair tips for fixing the OBDII code P0598 in a GMC?

- DIY repair tips may include checking and repairing any damaged wiring, replacing the thermostat if faulty, and ensuring proper connection of the thermostat heater control circuit.

7. Will resetting the OBDII code P0598 in my GMC make it go away permanently?

- Resetting the code may temporarily clear the check engine light, but if the underlying issue causing the code is not fixed, the code is likely to reappear.

8. How much does it cost to repair the OBDII code P0598 in a GMC at a mechanic?

- The cost of repairing the code P0598 can vary depending on the root cause of the issue, but it may range from $150 to $400 at a mechanic, including parts and labor.

9. Can the OBDII code P0598 in a GMC be a false alarm?

- While it's possible for a code to be triggered erroneously, it's important to properly diagnose and address the issue to prevent potential engine damage associated with overheating.

10. Are there any preventive measures to avoid the OBDII code P0598 in a GMC?

- Regular maintenance, such as checking and replacing the thermostat as recommended by the manufacturer, can help prevent issues that may lead to the code P0598.