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Fault code P0670 means a fault in the glow plug control module. The module managing the preheating does not respond correctly to the engine ECU.

Typical symptoms

• Flashing preheat light
• Hard cold starting
• Engine light on

Most common causes

• Failed preheat control unit
• Faulty module supply or ground
• Short on a glow plug damaging the module
• Communication with the engine ECU interrupted

How it is checked in diagnosis

• Checking the module supply and ground
• Checking the glow plugs before replacing the module
• Communication test in diagnosis

Can you drive with code P0670?

Yes, with difficulty starting when cold.

How MasterTuning helps

We read the real values from the ECU, not just the code: that is the difference between identifying the component responsible and replacing parts by trial and error. After the repair we clear the fault and check that it does not come back. Centres throughout Italy.

Read more: vehicle database · find an installer · what is ECU remapping

Do you have code P0670 on your car? Book a diagnosis at your nearest MasterTuning centre.

Frequently asked questions

What does fault code P0670 mean?

Code P0670 means a fault in the glow plug control module. The module managing the preheating does not respond correctly to the engine ECU.

Can you drive with fault P0670?

Yes, with difficulty starting when cold.

Is clearing code P0670 enough to fix it?

No: if the cause is still present the code comes back after a few kilometres. Clearing should only be done after the repair, with the diagnostic tool.

How much does it cost to fix code P0670?

It depends on the component responsible: the diagnosis is precisely what identifies it with real measurements, avoiding unnecessary replacements that cost far more than the correct repair.