P0683 Fault Code

Glow Plug Control Module to PCM Communication Circuit

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0683 fault code indicates a problem in the communication circuit between the glow plug control module and the powertrain control module (PCM). This code typically appears in diesel engines where glow plugs are used to assist with engine starting, particularly in cold conditions. Proper operation of this circuit is essential for efficient ignition and engine performance.

What are the symptoms of the P0683 code?

Common symptoms associated with a P0683 code may involve:

• Difficulty starting the engine, especially in cold weather
• Increased engine cranking time
• Rough idle or misfires after starting
• Possible check engine light illumination.
• Diagnostic trouble code stored in the PCM related to glow plug or fuel system.

What causes the P0683 code?

The causes of a P0683 fault may include:

• Faulty glow plug control module
• Wiring issues such as short circuits or open circuits
• Poor connection at the glow plug control module or PCM
• Malfunctions in the PCM itself
• Issues with any related sensors or components affecting the glow plug system.

How to fix P0683?

To resolve a P0683 fault code, the following steps are recommended:

• Inspect and test the glow plug control module for faults.
• Check the wiring and connectors for any signs of damage or corrosion.
• Use a multimeter to ensure that the communication signals between the glow plug control module and PCM are functioning.
• Replace any faulty wiring or connectors.
• If necessary, replace the glow plug control module or repair any related PCM faults.
• After repairs, clear the fault codes and test drive to confirm resolution.