P0670 is a diesel-only code meaning the engine control unit detected a fault in the glow plug control module circuit. The control module switches high current to the glow plugs that preheat the combustion chambers for cold starting and reports back to the ECU. The code points to the module itself, its supply or control wiring, or its ground rather than to one specific plug. Repairs typically run 70-350 EUR.
DTC/P0670·Volkswagen
P0670 on Volkswagen: Causes, Symptoms and Fix Cost
Quick Answer
Low SeveritySafe to drive (short-term)Volkswagen
P0670 on a Volkswagen is a diesel-only code meaning the engine control unit detected a fault in the glow plug control module circuit. The control module switches high current to the glow plugs that preheat the combustion chambers for cold starting and reports back to the ECU. The code points to the module itself, its supply or control wiring, or its ground rather than to one specific plug. Repairs typically run 70-350 EUR.
Repair cost on Volkswagen€2 - €407
What does P0670 mean on a Volkswagen?
Volkswagen Golf TDI
2005-2021On the Golf TDI the glow plug control module is a smart unit that monitors each plug and reports faults to the ECU. P0670 here is frequently the module itself or its connector, which can corrode. Replacement is straightforward but the part is genuine-VAG priced. Confirm power and ground at the module before ordering one.
What causes P0670 on a Volkswagen?
Beyond the generic causes listed on the main P0670 page, these are the Volkswagen-specific patterns we see most often:
Volkswagen Golf TDIGlow plug control module failure on TDI engines
Volkswagen Golf TDICorroded module connector triggering a circuit fault
How to diagnose P0670 on a Volkswagen with OBD2
Follow these steps to pinpoint the root cause of P0670:
- Read the stored code and freeze frame with Skanyx or any ELM327 adapter to confirm P0670 and note the conditions when it set
- Check the fuse feeding the glow plug control module, as a blown fuse can trigger the circuit fault
- Verify battery voltage at the module power supply pin and confirm a clean ground with a multimeter
- Inspect the connector and wiring between the ECU and the control module for corrosion, broken pins, or chafing
- Bench-test the glow plugs themselves with a multimeter (a healthy plug reads roughly 0.5-2 ohm) to rule out a dead plug dragging down the circuit before condemning the module
- Remember that detailed control module and per-plug status is manufacturer-extended (Mode $22) data that generic OBD2 does not expose, so module replacement is confirmed by supply, ground, and wiring checks plus the plug bench test
How much does P0670 cost to fix on a Volkswagen? (EUR)
Estimated repair costs on a Volkswagen (Volkswagen parts and labour typically run 10% above the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0670 on Volkswagen
These codes commonly cluster with P0670 on Volkswagen vehicles:
FAQ: P0670 on Volkswagen
Can I drive with a P0670 code?
Yes. The glow plug control module only matters for cold starting a diesel. Once the engine is warm it runs normally. You will get harder cold starts, more startup smoke, and the car will likely fail inspection until the fault is fixed.
What is the difference between P0670 and P0380?
P0380 is a general glow plug heater circuit "A" fault, while P0670 points specifically at the glow plug control module circuit. They often appear together. P0670 steers you toward the module, its wiring, and its power/ground rather than an individual plug.
Can a bad glow plug cause P0670?
Sometimes. A shorted glow plug can overload the control module and set a module circuit code. Bench-test each plug with a multimeter before replacing the module so you do not pay for a module that a failed plug killed.
How much does a glow plug control module cost?
The module itself usually costs 60-220 EUR depending on the vehicle, with another 60-150 EUR labor at a shop. Check the fuse, wiring, and ground first, since those are far cheaper fixes that produce the same code.
Does generic OBD2 show which glow plug is bad?
No. Generic OBD2 gives you the circuit code only. Per-cylinder glow plug status is manufacturer-extended Mode $22 data. To find the failed plug, bench-test each one with a multimeter; a healthy plug reads about 0.5-2 ohm.
Looking for the full P0670 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0670 guideSkanyx · Volkswagen
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