Quick Answer
P0599 means: The P0599 code means there's a thermostat control circuit issue that affects engine temperature regulation.
Can I drive with P0599? Immediate action is recommended to prevent engine damage.
Common Questions
What does P0599 mean and how does it affect my car?
The P0599 code signifies an issue with the thermostat control circuit. This can lead to your engine running too hot or too cold, impacting fuel efficiency and potentially causing engine damage over time.
What are the most common causes of P0599 and how much does it cost to fix?
Common causes include a faulty thermostat, wiring issues, and ECM failures. Repair costs can range from $120 to $300 for parts and labor, depending on the specific issue.
Can I drive my car with P0599 or should I stop immediately?
It's advisable to stop driving if you have a P0599 code, as continuing to operate the vehicle can lead to overheating and significant engine damage.
How can I diagnose P0599 myself using GeekOBD APP?
Using the GeekOBD APP, you can perform a complete OBD2 scan which will show you the P0599 code along with any additional codes. Look for freeze frame data that provides context on when the error occurred.
What vehicles are most commonly affected by P0599?
The P0599 code is frequently seen in vehicles like the 2015-2018 Ford F-150 and 2014-2017 Chevrolet Silverado, among others. Always check for recalls or Technical Service Bulletins (TSBs) related to this code.
How can I prevent P0599 from happening again?
Regular maintenance, including coolant flushes and thermostat inspections, can help prevent recurrence. Keeping an eye on your engine's temperature gauge can also alert you to issues early.
What is P0599?
The P0599 diagnostic trouble code indicates a problem with the thermostat control circuit, specifically relating to its range or performance. This code is often triggered when the Engine Control Module (ECM) detects that the thermostat isn't operating within its expected parameters. The thermostat is crucial for regulating the engine's temperature by controlling the flow of coolant to the radiator. When it's malfunctioning, it can lead to overheating or poor engine performance, which can be detrimental to your vehicle's longevity. Commonly reported in vehicles like the 2015-2018 Ford F-150 and 2014-2017 Chevrolet Silverado, this code can result in poor fuel economy, as the engine may run less efficiently when not at optimal temperature. If neglected, it might lead to severe engine damage, thereby incurring costly repairs. Understanding the implications of a P0599 code is critical for maintaining your vehicle's performance and reliability, especially in high-mileage conditions. Regular checks and timely repairs can help avoid further complications.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P0599 is present:
- Check engine light is illuminated, signaling a problem with the thermostat control circuit, which may affect engine performance.
- Engine overheating during operation, which can lead to potential engine damage if not addressed promptly.
- Poor fuel economy, often noticed by drivers as increased fuel consumption due to inefficient engine temperature management.
- Unusual engine performance, such as stalling or hesitating, particularly during acceleration when the engine isn't running at optimal temperature.
- Increased emissions can result from an improperly functioning thermostat, potentially leading to failed emissions tests.
Possible Causes
Most common causes of P0599 (ordered by frequency):
- Faulty thermostat (40% likelihood) - The most common issue is a thermostat that is stuck open or closed, preventing proper temperature regulation.
- Wiring issues (25% likelihood) - Damaged or corroded wiring in the thermostat control circuit can disrupt communication between the thermostat and the ECM.
- ECM failure (15% likelihood) - Although rare, a malfunctioning ECM can misinterpret signals from the thermostat or fail to control it properly.
- Coolant leaks (10% likelihood) - Insufficient coolant levels can affect thermostat performance and lead to overheating.
- Failed coolant temperature sensor (10% likelihood) - If the sensor is faulty, it may not provide accurate readings to the ECM, causing improper control of the thermostat.
P0599 Repair Costs
Cost Breakdown by Repair Type
Thermostat Replacement
Replacing the faulty thermostat with a new one to restore proper engine temperature regulation.
- Total: $120 - $300
- Success rate: 95%
Wiring Repair
Repairing or replacing damaged wiring in the thermostat control circuit.
- Total: $80 - $200
- Success rate: 85%
Money-Saving Tips for P0599
- Start with the most common and least expensive repairs first
- Use GeekOBD APP to confirm diagnosis before replacing expensive parts
- Consider preventive maintenance to avoid future occurrences
- Compare prices for OEM vs aftermarket parts based on your needs
- Address the issue promptly to prevent more expensive secondary damage
Diagnostic Steps
Professional P0599 Diagnosis Process
Follow these systematic steps to accurately diagnose P0599. Each step builds on the previous one to ensure accurate diagnosis.
Step 1: Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion, taking around 5-10 minutes
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion, taking around 5-10 minutes.
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context, which should take about 10-15 minutes
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context, which should take about 10-15 minutes.
Step 3: Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the thermostat and wiring for continuity and resistance, estimated time of 20-30 minutes
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the thermostat and wiring for continuity and resistance, estimated time of 20-30 minutes.
Step 4: Step 4: System function test - After repairs, verify proper operation by monitoring engine temperature and clearing codes, taking approximately 10-15 minutes
Step 4: System function test - After repairs, verify proper operation by monitoring engine temperature and clearing codes, taking approximately 10-15 minutes.
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to ensure the repair's effectiveness, typically lasting 15-20 minutes
Step 5: Road test verification - Drive the vehicle under various conditions to ensure the repair's effectiveness, typically lasting 15-20 minutes.
Important Notes
- Always verify the repair with GeekOBD APP after completing diagnostic steps
- Clear codes and test drive to ensure the problem is resolved
- Address underlying causes to prevent code recurrence
Real Repair Case Studies
Case Study 1: Thermostat Replacement in a 2016 Ford F-150
Vehicle: 2016 Ford F-150, 75,000 miles
Problem: Customer reported overheating and poor fuel economy.
Diagnosis: Diagnostic tests revealed a malfunctioning thermostat causing the engine to run too hot.
Solution: Replaced the thermostat and performed a coolant flush.
Cost: $250 (including parts and labor)
Result: After repairs, the engine temperature stabilized, and the customer reported improved fuel efficiency.
Case Study 2: Wiring Repair on a 2015 Chevrolet Silverado
Vehicle: 2015 Chevrolet Silverado, 60,000 miles
Problem: Check engine light on with P0599 code; vehicle running rough.
Diagnosis: Found damaged wiring in the thermostat control circuit.
Solution: Repaired the wiring and replaced the thermostat as a precaution.
Cost: $180 (including parts and labor)
Result: Post-repair, the check engine light cleared, and the vehicle ran smoothly.