P0620 Mercedes-Benz Code - Generator Control Circuit Malfunction
Quick Answer
This fault code is stored in a control module when the charging system control does not perform as expected. Common causes include Battery charge, Faulty Alternator, Alternator harness is open or shorted. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0620 Mercedes-Benz indicates Generator Control Circuit Malfunction.
- Common causes
- Common causes include Battery charge, Faulty Alternator, Alternator harness is open or shorted.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0620 Mercedes-Benz Description
What are the Possible Causes of the DTC P0620 Mercedes-Benz?
- Battery charge
- Faulty Alternator
- Alternator harness is open or shorted
- Alternator circuit poor electrical connection
- Faulty Engine Control Module (ECM)
How to Fix the DTC P0620 Mercedes-Benz?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0620 Mercedes-Benz code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P0620 Mercedes-Benz code?
Need more information on how to fix the P0620 Mercedes-Benz code? Get Access to Factory Service Manuals
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Frequently Asked Questions about P0620 Mercedes-Benz Code
1. What are the common symptoms of OBDII code P0620 in a Mercedes-Benz?
- Common symptoms include issues with generator charging, illuminated battery warning light, dimming lights, and potential stalling.
2. What can cause the OBDII code P0620 in a Mercedes-Benz?
- The code P0620 is typically triggered by a malfunction in the generator control circuit, which can be caused by a faulty generator, damaged wiring, or a failing generator control module.
3. How serious is the OBDII code P0620 in a Mercedes-Benz?
- The code P0620 should be addressed promptly as it can lead to charging system malfunctions, battery drain, and ultimately, vehicle stalling or failure to start.
4. How can I diagnose the OBDII code P0620 in my Mercedes-Benz?
- Diagnosis of code P0620 involves using a diagnostic scanner to retrieve the specific fault code, testing the generator output, and inspecting the control circuit components for any visible damage.
5. Can I drive my Mercedes-Benz with the OBDII code P0620?
- It is not recommended to continue driving your vehicle with code P0620, as it can lead to unpredictable electrical system behavior and potential breakdowns.
6. What is the typical repair process for the OBDII code P0620 in a Mercedes-Benz?
- The repair process usually involves inspecting and repairing any damaged wiring, replacing a faulty generator or control module, and clearing the fault code from the vehicle's memory.
7. How much does it cost to fix the OBDII code P0620 in a Mercedes-Benz?
- The cost of fixing code P0620 can vary depending on the extent of the issue, replacement parts needed, and labor costs. It is advisable to consult a professional mechanic for an accurate estimate.
8. Can a DIY enthusiast fix the OBDII code P0620 in a Mercedes-Benz?
- While some DIYers with experience in automotive repair may be able to address code P0620, it is recommended to seek assistance from a qualified mechanic due to the complexities involved in the electrical system.
9. Are there any preventive measures to avoid the OBDII code P0620 in a Mercedes-Benz?
- Regular maintenance, such as checking the battery, charging system, and electrical connections, can help prevent issues that may lead to code P0620 in a Mercedes-Benz.
10. How long does it take to repair the OBDII code P0620 in a Mercedes-Benz?
- The repair time for code P0620 can vary depending on the exact cause of the issue, availability of parts, and the skill level of the mechanic. It is advisable to consult with a professional for a more accurate timeframe.
Discuss the causes and fixes for P0620 Mercedes-Benz OBDII Code
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Alternator battery light goes on, I replaced battery and alternator but problem still exist. Any help or comment
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Error message Po620 battery/charge light on. Battery and alternator replaced but problem still exists
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I'm having the same problem. Replaced voltage regulator replaced (was putting out 16.5V, and causing several other problem, battery was also going dead overnight). Everything is fixed except warning light still comes on. Voltage now 14.2-14.4.
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How long it takes for the light to come back? Replacing the regulator should have take care of the problem. There is a factory service bulletin that could help you inspect the regulator and alternator: https://goo.gl/J6ThHM
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It doesn't seem consistent, but usually within the first 30s to 1min. I'll check the bulletin. One other thing I should mention, which I went to the dealer ship regarding and didn't get a good answer, they just wanted to replace parts..
The voltage regulator, which was listed as the replacement online was actually the wrong part. It was Bosch, and identical in every way, voltage output e.t.c.. but the plug insertion grooves were opposite. Since I couldn't return it I removed the grooves so the plug would fit (since I couldn't return it anyway). I don't doubt that that could be the issue, however, considering the voltage was high (16.5V), I would like to find out if that possibly killed a relay of fuse before replacing another voltage reg and still have the same issue.
There are two prongs coming from the VR but the plug only uses one of them. The voltage coming from the plug (to the ECU) is also 14.2..
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And thanks, helpful bulletin! Tells me I don't have two-way communication from ECU and VR, and if my output voltage is correct, maybe the other prong is for input voltage to control the VR?
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Well, that wasn't it. The other prong is just a lower voltage and can't find a VR schematics for individual models. Think I going to have to purchase the actual VR and go from there. Thanks for the help!
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