Generic Diesel Fault Code
Free · no signupP0673
Cold Start Misfire / White Smoke on Startup
System
Starting / Pre-Heat
Symptom
Cold Start Misfire / White Smoke on Startup
Diagnosis & fix steps
LOGIC: Cylinder 3 Glow Plug Circuit / Open.
ACTION: Measure Cylinder 3 glow plug resistance to ground (spec: ~0.5–2.0Ω). Inspect the harness boot for oil saturation, thermal embrittlement, or loose terminal pin tension. Perform a live load test on the driver circuit output from the GPCM pinout.
Red Seal field insights
Harness & Module Degradation: Under-valve-cover or engine-mounted glow plug harnesses suffer insulation cracking from heat and oil mist. A high-resistance contact in the harness connector drops current below the GPCM sensing threshold, setting the open-circuit flag.
Same code keeps coming back?
That's a program problem, not a part problem. Book a 30-minute uptime review with Grant, a Red Seal Heavy Duty Technician.
Read before you touch anything
- This is general reference information, not a repair manual. It is for trained, qualified technicians.
- Fault codes, meanings and procedures vary by model, serial number and software version. Confirm the code and the procedure against the manufacturer's service manual before acting.
- Follow the OEM service manual, torque specs and your site's safety procedures: lockout/tagout, block raised equipment, relieve hydraulic, fuel and air pressure, and let hot systems cool.
- You use this information at your own risk. Adventure Mechanical and AM Fleet Integrity accept no liability for damage, injury, downtime or loss arising from its use.
- Not affiliated with or endorsed by any manufacturer. Brand names are used only to identify the equipment a code applies to.
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