Engine-CodesGMC – P0670 GMC

P0670 GMC Code - Glow Plug Module Control Circuit

Quick Answer

The P0670 diagnostic trouble code (DTC) for GMC vehicles indicates a problem with the glow plug module control circuit. Common causes include Faulty glow plug module, Defective glow plugs, Damaged wiring or connectors. 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
P0670 GMC indicates Glow Plug Module Control Circuit.
Common causes
Common causes include Faulty glow plug module, Defective glow plugs, Damaged wiring or connectors.
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.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code P0670 GMC Description

The P0670 diagnostic trouble code (DTC) for GMC vehicles indicates a problem with the glow plug module control circuit. Glow plugs are essential components in diesel engines, as they heat up the air in the combustion chamber to facilitate ignition when the engine is cold. The glow plug module controls the operation of the glow plugs, ensuring they heat up at the right time and for the appropriate duration.

OBDII Code P0670 GMC - Glow Plug Module Control Circuit
P0670 GMC Code - Glow Plug Module Control Circuit

Common Causes of P0670 GMC

  1. Faulty glow plug module
  2. Defective glow plugs
  3. Damaged wiring or connectors
  4. Corrosion or poor connections in the circuit
  5. Electrical issues such as blown fuses or relays

Symptoms of P0670 GMC

  1. Difficulty starting the engine, especially in cold weather
  2. Engine misfires or runs rough
  3. Decreased fuel efficiency
  4. Increased emissions
  5. Engine may not start at all in severe cases

How to Fix P0670 GMC

  1. Diagnose the root cause of the issue using a scan tool to retrieve the DTC and inspecting the glow plug module, wiring, and connectors for any visible damage.
  2. Test the glow plugs for proper operation using a multimeter to check for continuity and resistance.
  3. Replace any faulty components such as the glow plug module, glow plugs, wiring, or connectors as needed.
  4. Clear the DTC from the vehicle's computer using a scan tool and test the vehicle to ensure the issue has been resolved.
  5. Perform a cold start test to confirm that the glow plug module control circuit is functioning correctly.

Cost to Fix P0670 GMC

The cost of repairing a glow plug module control circuit issue can vary depending on the extent of the damage and the specific components that need to be replaced. On average, the parts for this repair can range from $100 to $300, while labor costs can add another $100 to $200. Overall, the total repair cost may fall between $200 and $500. However, it's important to note that prices can vary based on factors such as location, vehicle make and model, and the shop's labor rates. It's recommended to obtain quotes from multiple auto repair shops to get a more accurate estimate for your specific situation.

When is the Code Detected?

The Engine Control Module (ECM) has detected a fault on the Glow Plug Control Module (GPCM) control circuit

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0670 GMC Code

1. What does the OBDII code P0670 mean on a GMC vehicle?

Code P0670 indicates an issue with the Glow Plug Module Control Circuit, which manages the operation of glow plugs in diesel engines.

2. What are the common symptoms of P0670 on a GMC?

Symptoms may include difficulty starting the engine, rough idle in cold weather, reduced fuel efficiency, and an illuminated check engine light.

3. What causes the P0670 code in GMC vehicles?

Common causes include a faulty glow plug control module, damaged wiring or connectors in the control circuit, or a blown fuse.

4. Can a bad glow plug cause the P0670 code?

While the code typically points to the control module or its circuit, a bad glow plug could indirectly cause issues if it leads to electrical system strain.

5. How is the P0670 code diagnosed in GMC vehicles?

A technician will inspect the wiring and connectors, test the glow plug control module for proper operation, and may use a multimeter to check circuit continuity.

6. Can I drive my GMC with the P0670 code present?

Driving is possible, but starting the engine may be difficult in cold weather, and prolonged use without repairs could lead to further damage.

7. How do you fix the P0670 code on a GMC?

Repairs may include replacing the glow plug control module, repairing or replacing damaged wiring, or replacing blown fuses.

8. How much does it cost to fix the P0670 code on a GMC?

Costs vary but typically range from $200 to $500, depending on whether the module, wiring, or other components need replacement.

9. Can I clear the P0670 code without fixing the problem?

Clearing the code without addressing the issue may temporarily turn off the check engine light, but the code will likely return.

10. What GMC models are commonly affected by the P0670 code?

GMC diesel models such as the Sierra 2500HD or 3500HD equipped with Duramax engines are more prone to this code due to their glow plug systems.

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