P2684 moderate

Glow Plug 2 Circuit Open

The P2684 code means the vehicle's onboard diagnostic system has detected: Glow Plug 2 Circuit Open. This is a moderate severity code.

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Keep driving?
Short distances only
DIY difficulty
moderate
Estimated cost
$100 - $300 (parts and labor)
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Common Symptoms

  • Check Engine Light on
  • Cold start roughness
  • Slight misfire on cylinder 2 when cold
  • White smoke from exhaust on startup
  • Normal operation once engine is warm

Probable Causes (Ranked by Likelihood)

  • Failed glow plug in cylinder 2 Very High
  • Open wiring to cylinder 2 glow plug High
  • Glow plug seized and broken during removal attempt Moderate
  • Control module output channel fault Low

Step-by-Step Diagnostic Procedure

  1. Read freeze frame data and confirm P2684 is stored

  2. Test cylinder 2 glow plug resistance

  3. Inspect glow plug connector for corrosion

  4. Verify glow plug module is sending power to cylinder 2

Frequently Asked Questions

What does P2684 mean?

P2684 indicates a problem with the glow plug 2 circuit open. Glow plugs are essential for cold-starting diesel engines by preheating the combustion chambers.

Can I drive with a P2684 code?

You can drive short distances once the engine is running. The main issue is cold starting difficulty. In warm weather, the effect is minimal, but cold weather starting will be significantly impacted.

How much does it cost to fix P2684?

Repairs typically cost $100 - $300. Individual glow plugs are $20 to $50 each, but labor can be significant if they are seized in the cylinder head.

Sources

This page is built from documented references. Verify against your own service info before repair work.

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