Battery, charging and glow plugs

P0670 Fault in the glow plug control module

By: Diagno editorial team · Updated: 2026-10-15

P0670 means: Fault in the glow plug control module. Glow plugs heat the diesel cylinders before starting. OK to drive, but have it checked soon. The repair usually costs about €60–400 in Estonia. The most common cause: glow plug has failed. Other possible causes: glow plug wire or connector, glow plug control module.

Is it safe to drive?OK to driveOK to drive, but have it checked soon.

Typical repair cost€60–400parts and labour in Estonia

What it means

Glow plugs heat the diesel cylinders before starting. With this fault the engine starts poorly in the cold and smokes.

What could be wrong

1Glow plug has failed
2Glow plug wire or connector
3Glow plug control module

What you can check yourself

Notice whether the car is hard to start when cold. In summer you may not notice the fault at all. You can check the simple things yourself, but the repair is best done in a workshop.

How we fix it

We measure the resistance of each glow plug
We check the control module and wiring
We replace the failed plugs

Standard SAE description: Glow Plug Control Module Circuit

This code usually comes with: Glow plug light (diesel)See what the light means →

Related symptoms: Smoke from the exhaust

Check the fuse · If a light, the horn, wipers, a socket or the fuel pump is dead, a blown fuse may be the cause.Fuse boxes by car →

Want a definite answer?

Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.

Book a diagnostic check

Questions

What does fault code P0670 mean?

Fault in the glow plug control module. Glow plugs heat the diesel cylinders before starting. With this fault the engine starts poorly in the cold and smokes.

Can I drive with code P0670?

OK to drive, but have it checked soon.

How much does it cost to fix P0670?

Roughly €60–400 in Estonia. The price depends on exactly what has failed and on the car.

How is P0670 fixed?

We measure the resistance of each glow plug. We check the control module and wiring. We replace the failed plugs.

Based on AI combined with our hands-on workshop experience and knowledge. This information is general and prices are approximate (Estonian workshop rates). The same code can mean different things on different cars. Only an inspection of the car gives a definite answer.