P0673 GMC Code - Cylinder 3 Glow Plug Circuit Fault
Quick Answer
n the diesel engine, air alone is compressed in the cylinder. Common causes include Faulty cylinder #3 glow plug, Cylinder #3 glow plug harness is open or shorted, Cylinder #3 glow plug circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0673 GMC indicates Cylinder 3 Glow Plug Circuit Fault.
- Common causes
- Common causes include Faulty cylinder #3 glow plug, Cylinder #3 glow plug harness is open or shorted, Cylinder #3 glow plug circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0673 GMC Description
Control of the glow plugs is accomplished by the Glow Plug Control Module. The nominal voltage for the glow plugs is 5.4 volts. When the ignition is turned On, the Glow Plug Control Module applies 7.2 V for 2.2 s, then 5.7 V for 0.8 s, and then 5.4 V until 1200°C (2192°F) is reached. The maximum voltage of the system is 10 V. While the engine is running the voltage will vary between 4.7 - 10 V when in closed loop control to maintain a glow plug temperature that ranges from 1150° - 1180°C (2102° - 2156°F). The temperature and the power consumption are controlled between the Engine Control Module (ECM) and the Glow Plug Control Module within a wide range to suit the engine's pre-heating requirements. Each glow plug is energized individually. This capability yields more optimum heat times for the glow plugs, thus pre - glow times can be kept to a minimum for a short wait to crank times and maximum glow plug durability.
What are the Possible Causes of the DTC P0673 GMC?
- Faulty cylinder #3 glow plug
- Cylinder #3 glow plug harness is open or shorted
- Cylinder #3 glow plug circuit poor electrical connection
- Faulty Glow Plug Control Module (GPCM)
How to Fix the DTC P0673 GMC?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0673 GMC code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P0673 GMC code?
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Information for Specific GMC Models
- P0673 2014 GMC Sierra — Cylinder 3 Glow Plug Circuit Fault
- P0673 2015 GMC Sierra — Cylinder 3 Glow Plug Circuit Fault
- P0673 2016 GMC Sierra — Cylinder 3 Glow Plug Circuit Fault
- P0673 2017 GMC Sierra — Cylinder 3 Glow Plug Circuit Fault
- P0673 2018 GMC Sierra — Cylinder 3 Glow Plug Circuit Fault
Frequently Asked Questions about P0673 GMC Code
1. What does the OBDII code P0673 mean on a GMC vehicle?
P0673 indicates a fault in the glow plug circuit for cylinder 3, which may affect the engine's ability to start in cold conditions.
2. What are the common symptoms of code P0673?
Common symptoms include difficulty starting the engine in cold weather, rough idle, reduced fuel efficiency, and the check engine light illuminating.
3. What causes a P0673 code to appear?
The code can be triggered by a faulty glow plug, damaged glow plug wiring, a bad glow plug control module, or a poor electrical connection in the circuit.
4. Can I drive my GMC with a P0673 code?
While the vehicle may still be drivable, starting difficulties and reduced performance in cold weather could occur. It's best to address the issue promptly to avoid further damage.
5. How do I diagnose a P0673 code?
Use a multimeter to check the resistance of the cylinder 3 glow plug, inspect the wiring and connectors for damage, and test the glow plug control module for proper operation.
6. How do I fix the P0673 code on my GMC?
Repairs may include replacing the faulty glow plug, repairing damaged wiring or connectors, or replacing the glow plug control module if it's defective.
7. How much does it cost to fix a P0673 code?
The cost depends on the exact issue. Replacing a glow plug typically costs $50–$150, while addressing wiring or control module issues may cost more.
8. Can a bad glow plug cause other problems in my GMC?
Yes, a bad glow plug can lead to poor engine performance, difficulty starting, and potential damage to other engine components if left unresolved.
9. How can I prevent a P0673 code from recurring?
Regular maintenance, including inspecting the glow plug system and addressing issues promptly, can help prevent the code from recurring.
10. Does the P0673 code affect all GMC vehicles the same way?
The impact may vary depending on the model and engine type, but the code generally indicates the same issue with the cylinder 3 glow plug circuit.
Discuss the causes and fixes for P0673 GMC OBDII Code
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I changed the #3 glow plug and cleared the code, next day engine light was back on, now I’m thinking about changing the ECM, don’t know if I’m going the right route or not but all that would be left is changing the harness, I hope I’m right
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