Error code P0620 is displayed and the check engine light is on - what does this mean?
The DTC P0620 is recognized by the OBD system when a problem is detected with the alternator control unit (alternator). This fault code indicates a malfunction in the charging system that is preventing the control unit from communicating properly with the alternator. With various manufacturers, this trouble code can also be referred to as "alternator control circuit malfunction".
What causes can this error code have?
- Defective alternator or alternator regulator
- Damaged cable connections to the alternator
- Loose or corroded plug connections
- Defective engine control unit (ECM/PCM)
- Interrupted ground or voltage supply
- Faulty alternator control circuit
- Faulty fuses in the charging system
- Worn carbon brushes in the alternator
What symptoms occur in parallel with fault code P0620?
- Battery light: The battery warning light in the dashboard lights up
- Weak lighting: Headlights and interior lighting become dimmer
- Starting problems: The vehicle is difficult or impossible to start
- Electrical failures: Various electrical systems are not working properly
- Battery discharging: The vehicle battery is continuously losing charge
- Engine power loss: Reduced engine power due to insufficient power supply
How to fix the problem of error code P0620?
- Repairing EOBD fault code P0620 requires a systematic approach to identifying the faulty component.
- Check and replace the alternator and regulator if it is not supplying sufficient voltage (13.5-14.5V) or has mechanical defects
- Repair or replacement of the cable connections between the alternator and control unit, including testing for continuity and insulation resistance
- Cleaning and renewal of all plug connections in the charging system with contact spray and ensuring tight connections
- Replacement of the engine control unit after prior diagnosis if other components are intact but communication remains faulty
- Checking and replacing defective fuses and repairing the associated fuse holders in the charging system
- Replacement of the ground cable between the alternator and the body and testing of the main power supply from the alternator to the battery
FAQ - Frequently asked questions about DTC P0620
Can I continue driving with fault code P0620?
It is only possible to continue driving with code P0620 to a very limited extent, as the battery is not being charged. You should visit a workshop immediately, as the battery will discharge and the vehicle may come to a standstill.
How much does it cost to repair error code P0620?
The repair costs for dtc P0620 vary between 150-800 euros, depending on the cause. A new alternator costs around 300-600 euros, while cable repairs are usually less than 200 euros.
How can I diagnose fault code P0620 myself?
You can check the alternator voltage with a multimeter (should be 13.5-14.5V with the engine running) and visually check the cable connections for damage. However, specialist knowledge is required for a complete diagnosis.
Is the error code P0620 manufacturer-specific?
No, P0620 is a standardized OBD-II fault code that has the same basic meaning for all manufacturers. However, the specific repair procedures may vary depending on the vehicle model.
Can a weak battery trigger fault code P0620?
A faulty battery can indirectly contribute to fault code P0620, but is usually not the main cause. The problem often lies in the alternator itself or its control circuit.
How long does it take to repair error code P0620?
The repair time depends on the cause. Simple cable repairs take 1-2 hours, while replacing an alternator can take 2-4 hours.
How to change front wheel bearing on MERCEDES-BENZ M W163 TUTORIAL | AUTODOC
How to change fuel filter BMW 3 (E90) [TUTORIAL AUTODOC]
How to change Front wheel bearing on VW GOLF 4 TUTORIAL | AUTODOC
How to change a rear brake pads FORD FOCUS 3 TUTORIAL | AUTODOC
How to change pollen filter / cabin filter on AUDI A6 (C6) [TUTORIAL AUTODOC]
How to change engine thermostat on PEUGEOT 207 [TUTORIAL AUTODOC]
How to change fuel filter NISSAN X-TRAIL T30 TUTORIAL | AUTODOC
How to change front wheel bearing TOYOTA YARIS XP10 TUTORIAL | AUTODOC
Free download PDF
1.38 MB
Free download PDF
Free download PDF
Free download PDF
Free download PDF
Free download PDF
Ask on the forum
Top 5 mistakes when replacing spark plugs | AUTODOC tips
How to tell if a tie rod is faulty
How to restore a steering wheel | AUTODOC tips
DIY starter repair | AUTODOC tips
