The P0683 trouble code is a diagnostic trouble code (DTC) that indicates a communication issue between the glow plug control module and the powertrain control module (PCM). This code is primarily associated with diesel engines, where glow plugs are essential for starting the engine, especially in cold weather. When the PCM detects a malfunction in the glow plug control circuit, it triggers the P0683 code, which can lead to starting difficulties and other performance issues.
| P0683 Code Meaning | P0683 Code Common Causes |
|---|---|
| Glow Plug Control Module to PCM Communication Circuit | Faulty glow plug control module |
| Communication failure between modules | Damaged wiring or connectors |
| Glow plug relay malfunction | Faulty glow plugs |
| Blown fuses in the circuit | Faulty PCM |
Symptoms of P0683 Code
When the P0683 code is triggered, you may experience various symptoms that can affect your vehicle’s performance:
- Difficulty Starting: The engine may take longer to start, particularly in cold conditions.
- Prolonged Cranking: The vehicle may require multiple attempts to start.
- Check Engine Light: The check engine light (MIL) will illuminate on the dashboard.
- Irregular Engine Performance: The engine may run roughly or misfire when cold due to inadequate preheating.
- Excessive Exhaust Smoke: Increased white or gray smoke from the exhaust can occur during difficult starts.
Technical Explanation
The P0683 code is related to the glow plug control system, which is crucial for diesel engines. Glow plugs preheat the combustion chamber to facilitate easier starting, especially in colder temperatures. The PCM sends signals to the glow plug control module, which activates the glow plugs. If there is a communication failure between these components, it can lead to improper functioning of the glow plugs, resulting in hard starts or no starts at all.
Step-by-Step Diagnosis
To diagnose the P0683 trouble code effectively, follow these steps:
- Read Trouble Codes: Use an OBD-II scanner to confirm the presence of the P0683 code and check for any additional codes that might provide more context about the issue.
- Visual Inspection: Inspect the wiring and connectors associated with the glow plug control module and PCM for any signs of damage, corrosion, or loose connections.
- Test Glow Plug Relay: Using a multimeter, test the relay for continuity and proper operation. Ensure it activates when commanded by the PCM.
- Check Glow Plugs: Measure resistance across each glow plug using a multimeter. A reading outside of manufacturer specifications indicates a faulty glow plug.
- Inspect Fuses: Check for any blown fuses in the circuit that could interrupt power supply to the glow plugs.
- Evaluate PCM Functionality: If all other components are functioning correctly, consider testing or replacing the PCM if it fails to communicate properly with the glow plug control module.
Solution Methods
Once you have diagnosed the cause of the P0683 code, you can proceed with appropriate repairs:
- Replace Faulty Glow Plug Control Module: If testing reveals that the module is not functioning correctly, replace it with a new unit.
- Repair Damaged Wiring or Connectors: Any damaged wiring should be repaired or replaced to ensure proper electrical flow.
- Replace Glow Plugs: If one or more glow plugs are faulty, they should be replaced to restore proper engine starting capabilities.
- Replace Blown Fuses: Ensure all fuses in the preheating circuit are intact; replace any that are blown.
- Repair or Replace PCM: If all else fails and communication issues persist, consider having a professional evaluate and possibly replace your PCM.
Cost Estimates
The cost of repairs related to a P0683 code can vary widely depending on several factors:
- Glow Plug Control Module Replacement: $100 – $300
- Glow Plug Replacement (each): $50 – $150
- Wiring Repairs: $50 – $200 depending on labor and extent of damage
- PCM Replacement: $300 – $1,200 depending on vehicle make and model
- Diagnostic Fees: Typically range from $75 – $150 for professional diagnostics.
Warnings and Recommendations
Important: Always ensure you have disconnected your vehicle’s battery before working on electrical components to avoid short circuits or further damage.
If you are not comfortable performing these diagnostics and repairs yourself, it is highly recommended to seek professional assistance from an ASE-certified technician. Misdiagnosing or improperly repairing electrical issues can lead to further complications and increased repair costs.
Frequently Asked Questions About P0683
- What does error code P0683 mean?
The P0683 error code indicates a communication failure between the glow plug control module and the powertrain control module. - Can I drive my vehicle with a P0683 code?
While it may be possible to drive your vehicle, doing so could lead to starting difficulties and potential engine performance issues. - How serious is a P0683 code?
A P0683 code should be addressed promptly as it can affect your vehicle’s starting capabilities and overall performance. - What tools do I need to diagnose a P0683 code?
You will need an OBD-II scanner, multimeter, and basic hand tools for inspection and repairs. - How much does it cost to fix a P0683 code?
The cost can range from $100 for minor repairs up to $1,200 for PCM replacement. - Can I reset my check engine light after fixing P0683?
Yes, after repairs are made, you can use an OBD-II scanner to clear the codes; however, ensure all issues are resolved first. - What if my vehicle still has problems after fixing P0683?
If issues persist after repairs, further diagnosis may be necessary as there could be additional underlying problems. - Is there a way to prevent P0683 from occurring?
Regular maintenance of your vehicle’s electrical systems and timely replacement of worn components can help prevent this error.
In conclusion, understanding and addressing a P0683 trouble code is crucial for maintaining optimal performance in diesel vehicles. By following proper diagnostic procedures and addressing any identified issues promptly, vehicle owners can ensure their engines start smoothly and operate efficiently under various conditions.