Error code P0670 is displayed and the check engine light is on - what does this mean?
The DTC P0670 is recognized by the OBD-II/EOBD system when there is a problem in the glow plug control circuit. This fault code mainly affects diesel vehicles and indicates that the glow plug control system is not working properly. For various manufacturers, this code may also be referred to as the "Glow Plug Control Module Circuit".
What causes can this error code have?
- Defective glow plug control unit
- Damaged wiring to the glow plug module
- Corroded or loose plug connections
- Blown fuse in the glow plug circuit
- Defective glow plug relay
- Short circuit in the electrical cable
- Faulty ground connection of the control unit
- Defective ECU (engine control unit)
What symptoms occur in parallel with fault code P0670?
- Starting problems: The vehicle is difficult to start, especially in cold temperatures, or does not start at all
- Extended starting time: The engine takes significantly longer to start than usual
- White smoke: More white smoke comes out of the exhaust during a cold start
- Engine restlessness: The engine runs unevenly, especially during the warm-up phase
- Reduced performance: Noticeable reduction in performance, especially at low engine speeds
How can the problem with error code P0670 be rectified?
- Repairing trouble code P0670 requires a systematic approach to identify the defective component.
- Check and replace the fuse in the glow plug circuit and check all electrical connections for corrosion or damage
- Replacement of the defective glow plug control unit after prior diagnosis with a professional OBD scanner
- Repair or replacement of the wiring between the ECU and glow plug module, including all plug connections
- Replacing the glow plug relay in the fuse box and checking the relay function
- Cleaning and securing all ground connections of the glow plug system
- Professional diagnosis and, if necessary, replacement of the engine control unit in the event of more complex faults
FAQ - Frequently asked questions about DTC P0670
Can I continue driving with error code P0670?
Driving is possible in the short term, but you should have fault code P0670 rectified as soon as possible. At warm temperatures, diesel engines can also start without functioning glow plugs, but starting becomes increasingly problematic in cold weather.
How much does it cost to repair fault code P0670?
The costs vary depending on the cause: fuses cost 5-15 euros, glow plug relays 20-50 euros, a glow plug control unit 150-400 euros. The working time is usually 1-3 hours, which means additional workshop costs of 80-240 euros.
Does the code P0670 only occur at certain temperatures?
Error code P0670 is stored regardless of the temperature, but the symptoms are much more noticeable at cold temperatures, as diesel engines then rely on functioning glow plugs.
Can I repair fault code P0670 myself?
Simple repairs such as replacing fuses or relays can be carried out by non-professionals. In the event of problems with the control unit or more complex electrical faults, you should visit a specialist workshop, as special diagnostic equipment is required.
How long does it take to diagnose EOBD code P0670?
A professional diagnosis usually takes 30-60 minutes. Basic information can be read out immediately using an OBD scanner, but further measurements of the electrical components are required to localize the exact source of the fault.
Does the error code P0670 lead to an MOT failure?
Yes, if the check engine light is permanently illuminated, this leads to an MOT refusal. In addition, starting problems and increased emission values during a cold start can have a negative impact on the emissions test.