AutoCodes – Generic – P0598

P0598 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, Engine Cooling Thermostat harness is open or shorted, Engine Cooling Thermostat 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 indicates Thermostat Heater Control Circuit Low.
Common causes: Common causes include Failed Engine Cooling Thermostat, Engine Cooling Thermostat harness is open or shorted, Engine Cooling Thermostat 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 31,783

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

What does this mean?

What are the Possible Causes of the DTC P0598?

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

How to Fix the DTC P0598?

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

If there are no coolant system leaks, replace the thermostat to fix the problem.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0598 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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Information for Specific Makes

P0598 Audi — Thermostat Heater Control Circuit Low
P0598 BMW — Thermostat Heater Control Circuit Low
P0598 Buick — Thermostat Heater Control Circuit Low
P0598 Cadillac — Thermostat Heater Control Circuit Low
P0598 Chevrolet — Thermostat Heater Control Circuit Low
P0598 GMC — Thermostat Heater Control Circuit Low
P0598 Mercedes-Benz — Thermostat Heater Control Circuit Low
P0598 MINI — Thermostat Heater Control Circuit Low
P0598 Volkswagen — Thermostat Heater Control Circuit Low

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 Code

1. What does the OBDII code P0598 mean?

Code P0598 indicates a low voltage issue in the thermostat heater control circuit, which helps regulate engine temperature through the electronically controlled thermostat.

2. What are the common symptoms of code P0598?

Symptoms may include engine overheating or failing to reach operating temperature, reduced fuel efficiency, and the Check Engine Light being illuminated.

3. What causes code P0598?

Common causes include a faulty thermostat heater, damaged wiring or connectors in the heater control circuit, or issues with the engine control module (ECM).

4. Can I drive my car with code P0598?

While the vehicle may still be drivable, prolonged operation with this code can lead to engine temperature problems, which can cause further damage or reduced performance.

5. How do I diagnose code P0598?

Start by checking the thermostat heater wiring and connectors for damage, test the thermostat heater for proper operation, and use a multimeter to verify voltage and continuity in the control circuit.

6. How is code P0598 fixed?

Repairs may involve replacing the thermostat heater, repairing or replacing damaged wiring or connectors, or reprogramming or replacing the ECM if necessary.

7. What tools are needed to fix code P0598?

A diagnostic scanner, multimeter, and basic automotive tools like pliers and screwdrivers are typically needed to diagnose and repair this issue.

8. How much does it cost to fix code P0598?

Repair costs can range from $100 to $400, depending on whether the thermostat heater or ECM needs replacement and labor costs in your area.

9. Can a faulty thermostat cause engine damage?

Yes, if the thermostat fails to regulate engine temperature properly, it can lead to overheating or underheating, which may cause engine damage over time.

10. How can I prevent code P0598 from occurring?

Regularly inspect wiring and connectors for damage, ensure the coolant system is properly maintained, and address any Check Engine Light issues promptly.