Quick Answer
P0387 means: The P0387 code signifies a problem with the glow plug circuit's performance or range, particularly affecting diesel engines.
Can I drive with P0387? Immediate attention recommended to prevent starting issues and engine damage.
Common Questions
What does P0387 mean and how does it affect my car?
The P0387 code indicates a problem with your vehicle's glow plug circuit. This can lead to hard starting, especially in cold weather, and can affect engine performance and fuel efficiency. If your car struggles to start or runs roughly, it might be time to check the glow plugs and related components.
What are the most common causes of P0387 and how much does it cost to fix?
Common causes include faulty glow plugs, damaged wiring, or a malfunctioning glow plug control module. Repair costs can range from $200 to $800 depending on the specific issue and parts needed.
Can I drive my car with P0387 or should I stop immediately?
While you may be able to drive the car, it’s not advisable to ignore the P0387 code. Continuing to drive with this issue can lead to starting problems and potentially more serious engine issues. It’s best to have it diagnosed and repaired as soon as possible.
How can I diagnose P0387 myself using GeekOBD APP?
Using the GeekOBD APP, you can scan your vehicle for trouble codes, view live data, and check the performance of your glow plugs. Look for any anomalies in the readings, and compare them with manufacturer specifications to identify potential issues.
What vehicles are most commonly affected by P0387?
Vehicles such as the 2003-2007 Ford Super Duty and 2004-2010 Dodge Ram 2500 commonly experience the P0387 code due to their diesel engines relying heavily on glow plugs for starting.
How can I prevent P0387 from happening again?
Regular maintenance such as checking glow plugs during service intervals, ensuring electrical connections are clean and secure, and replacing any worn components can help prevent the recurrence of the P0387 code.
What is P0387?
The P0387 diagnostic trouble code indicates a malfunction in the glow plug circuit, specifically related to the glow plug control module or the glow plugs themselves. This code is particularly common in diesel engines, where glow plugs are critical for starting the engine, especially in cold weather. The glow plugs heat the combustion chamber, allowing for easier ignition of the diesel fuel. When the P0387 code is triggered, it usually means that there is an issue with the circuit's performance or range, which can result from faulty glow plugs, damaged wiring, or issues with the control module. If left unaddressed, this can lead to hard starting, rough idling, and increased emissions. Drivers may notice that their vehicle struggles to start or runs inefficiently, particularly in colder temperatures. It's crucial to tackle this issue promptly to avoid further damage to the engine or other related components. Regular maintenance and timely diagnostics can prevent the escalation of problems associated with P0387, ensuring your diesel vehicle runs smoothly and efficiently.
System: P - Powertrain (Engine, Transmission, Emissions)
Symptoms
Common symptoms when P0387 is present:
- Check engine light stays on constantly, indicating an ongoing issue that needs to be addressed.
- Engine hesitates during acceleration, which may feel like a lack of power or responsiveness when you press the gas.
- Fuel economy decreased by 10-15%, as a faulty glow plug can lead to incomplete combustion, causing the engine to work harder.
- Difficulties starting the vehicle in cold weather, as the glow plugs are essential for warming the combustion chamber.
- Rough idling once the engine is running, suggesting that there may be incomplete combustion due to improper glow plug operation.
Possible Causes
Most common causes of P0387 (ordered by frequency):
- Faulty glow plugs (65% likelihood) - Glow plugs can wear out over time, leading to inadequate heating of the combustion chamber.
- Damaged wiring or connectors (20% likelihood) - Corrosion or damage to the wiring can interrupt the circuit, causing the glow plugs to function improperly.
- Faulty glow plug control module (10% likelihood) - The control module that regulates the glow plugs may fail, leading to erratic performance.
- Less common but serious cause: ECM issues - Problems with the engine control module can lead to miscommunication in the glow plug circuit.
- Rare but possible cause: Short circuit in the glow plug circuit - This can lead to blown fuses or complete failure of the glow plug system.
P0387 Repair Costs
Cost Breakdown by Repair Type
Glow Plug Replacement
Replacing faulty glow plugs to restore proper engine operation.
- Total: $200 - $600
- Success rate: 90%
Glow Plug Control Module Replacement
Replacing the control module if it's found to be faulty.
- Total: $300 - $800
- Success rate: 85%
Wiring Repair
Repairing or replacing damaged wiring or connectors in the glow plug circuit.
- Total: $150 - $400
- Success rate: 80%
Money-Saving Tips for P0387
- 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 P0387 Diagnosis Process
Follow these systematic steps to accurately diagnose P0387. 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 (5-10 minutes)
Step 1: Initial visual inspection - Check for obvious signs like damaged wiring, loose connections, or corrosion (5-10 minutes).
Step 2: Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes)
Step 2: OBD2 scan with GeekOBD APP - Retrieve all codes and freeze frame data to understand the fault context (10-15 minutes).
Step 3: Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the glow plugs and control module (20-30 minutes)
Step 3: Component testing - Use a multimeter or specific diagnostic tools to test the glow plugs and control module (20-30 minutes).
Step 4: Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes)
Step 4: System function test - Verify proper operation after repairs and clear codes (10-15 minutes).
Step 5: Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success (15-20 minutes)
Step 5: Road test verification - Drive the vehicle under various conditions to confirm repair success (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: Glow Plug Replacement on 2005 Ford Super Duty
Vehicle: 2005 Ford Super Duty, 120,000 miles
Problem: Customer reported difficulty starting the vehicle, especially in cold weather.
Diagnosis: OBD2 scan revealed P0387. Visual inspection showed corrosion on wiring and one faulty glow plug.
Solution: Replaced the faulty glow plug and repaired damaged wiring.
Cost: $350 (parts and labor)
Result: Vehicle started smoothly after repair, customer reported no further issues.
Case Study 2: Control Module Replacement on 2006 Dodge Ram 2500
Vehicle: 2006 Dodge Ram 2500, 90,000 miles
Problem: Check engine light was on, and the engine hesitated during acceleration.
Diagnosis: P0387 code was present, and testing indicated a malfunction in the glow plug control module.
Solution: Replaced the glow plug control module.
Cost: $450 (including parts and labor)
Result: Post-repair test drive showed improved performance and no check engine light.