P0683Generic code

P0683 Code: Glow Plug Control Module to PCM Communication Circuit

The P0683 code means the engine computer is not receiving the diagnostic information from the glow plug control module correctly. It usually comes from wiring, a corroded module connector or the module itself. You can keep driving, but cold starting may suffer.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$30 to $600
Difficulty
Medium
System
Ignition and Misfires
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0683 code means

The glow plug control module reports the condition of the glow plugs to the computer over a dedicated diagnostic line. When that communication fails, the computer stores the P0683 code and it can no longer tell whether any glow plug is burned out.

The cause is usually the wiring, the module connector (which is often exposed to water) or the module itself.

On the Ford Power Stroke 6.0 and 6.4, the glow plug module sits on the driver side underneath the vehicle, where it is exposed to water and road salt. Its connector corrodes and sets a P0683 code even when the glow plugs are perfectly good. Clean the connector and protect it before you spend money on a new module.

P0683 code symptoms

  • Hard starting when the engine is cold.
  • Glow plug light on.

Likely causes of the P0683 code

  1. Water in the module connector. Very common on modules mounted under the vehicle or in the engine bay.
  2. Damaged diagnostic wire between the module and the computer.
  3. Glow plug module with damaged internal electronics.

How to diagnose the P0683 code step by step

  1. Inspect the connector for water, green corrosion and bent or pushed back pins.
  2. Check the continuity of the wire between the module and the computer.
  3. Clean and protect the module connector before you replace the module.

How to fix the P0683 code

  • Repair the connector or the wire.
  • Replace the module.

Technical reference data

  • Dedicated diagnostic line between the module and the computer.
  • Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

P0683 on Ford

The P0683 code is common on the Ford Power Stroke 6.0 and 6.4, where the module connector corrodes from water and salt.

Frequently asked questions about P0683

What does the P0683 code mean?
It means the computer is not receiving the diagnostic information from the glow plug control module correctly. The communication line, the connector or the module is at fault.
Can I drive with a P0683 code?
Yes. The engine will run, though cold starting can be harder, and the computer cannot spot a burned out glow plug while the code is set.
What usually fails?
Most often it is the module connector, which corrodes from water, or the module itself. Check the connector first because it costs almost nothing.
Does it affect starting?
It can. If the module is not working properly, the glow plugs may not heat the way they should, and the engine will crank longer when cold.
How much does it cost to fix P0683?
Between $30 and $600. A cleaned connector is cheap, while a new glow plug module with labor is at the top of that range.

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Questions about the P0683 code

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