P0670 Fault Code

Glow Plug Module Control Circuit

• What does that mean?
• Symptoms
• Causes
• Solutions

The P0670 fault code refers to an issue within the Glow Plug Module Control Circuit, which is critical for starting a diesel engine in cold conditions. The glow plugs are responsible for preheating the combustion chamber to ensure efficient ignition. If there's a malfunction in this circuit, the glow plugs may not function properly, leading to hard starting, rough idling, and increased emissions.

What are the symptoms of the P0670 code?

Symptoms associated with the P0670 code may include:

• Difficulty starting the engine, especially in cold weather
• Rough idle or poor engine performance during the first few minutes of operation
• Increased exhaust smoke upon startup
• Dashboard warning lights, such as the check engine light, being activated.

What causes the P0670 code?

Common causes of the P0670 code include:

• Faulty glow plug relay or module
• Open or short circuit in the glow plug circuit
• Bad glow plugs themselves
• Wiring issues such as corrosion or damage
• Faulty engine control module (ECM) that fails to properly control the glow plug circuit.

How to fix P0670?

To address the P0670 fault code, consider the following steps:

1. Inspect the glow plugs for wear or damage and replace if necessary.
2. Check the glow plug module and relay for proper operation and replace if faulty.
3. Examine wiring and connectors for corrosion or damage, repairing or replacing as needed.
4. Run a scan of the vehicle's computer to ensure there are no additional codes.
5. If all components check out, perform a thorough diagnostic of the engine control module.