Cylinder 2 Glow Plug Circuit
Code P0672 indicates a malfunction in the glow plug circuit for cylinder #2 in a diesel engine. The engine control module detected an electrical problem with the glow plug or its circuit, which prevents proper pre-heating of the combustion chamber during cold starts.
What You Might Notice
- Check engine light illuminated
- Difficulty starting engine in cold weather
- Engine hesitation or rough idle during cold start
- White smoke from exhaust on cold start
- Extended cranking time before engine fires
Most Common Causes
- 1
Failed glow plug
The glow plug in cylinder #2 has burned out or become defective. This is the most common cause and typically occurs after extended use.
- 2
Faulty glow plug relay
The relay controlling glow plug power delivery has failed, cutting electrical supply to the glow plug circuit. This affects the entire glow plug operation sequence.
- 3
Corroded or loose electrical connections
Poor connections at the glow plug terminals, harness connectors, or grounds prevent proper voltage from reaching cylinder #2's glow plug.
- 4
Damaged glow plug wiring harness
The wiring harness to cylinder #2 glow plug may be cracked, pinched, or corroded, interrupting the electrical circuit.
How to Diagnose It
- 1
Check Failed glow plug — The glow plug in cylinder #2 has burned out or become defective. This is the most common cause and typically occurs after extended use.
- 2
Check Faulty glow plug relay — The relay controlling glow plug power delivery has failed, cutting electrical supply to the glow plug circuit. This affects the entire glow plug operation sequence.
- 3
Check Corroded or loose electrical connections — Poor connections at the glow plug terminals, harness connectors, or grounds prevent proper voltage from reaching cylinder #2's glow plug.
- 4
Check Damaged glow plug wiring harness — The wiring harness to cylinder #2 glow plug may be cracked, pinched, or corroded, interrupting the electrical circuit.
How to Fix It
- 1
Replace cylinder #2 glow plug
Remove the failed glow plug from cylinder #2 and install a new OEM or equivalent replacement. Ensure proper torque specification is followed during installation to avoid damage.
- 2
Inspect and test glow plug relay
Test the glow plug relay with a multimeter or have it bench tested. Replace the relay if it fails continuity or voltage tests during glow cycle operation.
- 3
Clean and inspect electrical connections
Remove corrosion from glow plug terminals and wiring connectors using a wire brush. Apply dielectric grease and ensure all connections are tight and secure.
- 4
Repair or replace glow plug harness
Inspect the entire wiring harness to cylinder #2 for damage, cuts, or poor connections. Repair damaged sections with proper automotive wiring and connectors, or replace the entire harness if severely compromised.
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