AutoCodes – Generic – P0620

P0620 Code - Generator Control Circuit Malfunction

Quick Answer

The Engine Control Module (ECM) uses the generator turn ON signal circuit to control the generator. Common causes include Battery charge, Faulty Voltage Regulator, Faulty Generator. 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 indicates Generator Control Circuit Malfunction.
Common causes: Common causes include Battery charge, Faulty Voltage Regulator, Faulty Generator.
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.

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Code Popularity 76,034

How popular is this code, among other codes? Medium

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on May 04, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0620 Description

The Engine Control Module (ECM) uses the generator turn ON signal circuit to control the generator. A high side driver within the ECM allows the ECM to turn the generator ON and OFF. When Generator operation is desired, the ECM sends a 5 volt signal to the voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling the generator field circuit. Once the Generator is enabled by the ECM, the voltage regulator controls generator output independently of the ECM. Under certain operating conditions, the ECM can turn Off the generator by turning Off the 5 volt signal on the generator turn on signal circuit.

OBDII Code P0620 - Generator Control Circuit Malfunction - AutoCodes.com — P0620 Code - Generator Control Circuit Malfunction

What does this mean?

What are the Possible Causes of the DTC P0620?

Battery charge
Faulty Voltage Regulator
Faulty Generator
Generator harness is open or shorted
Generator circuit poor electrical connection
Engine Control Module (ECM) controlled generator
Faulty ECM

How to Fix the DTC P0620?

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.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0620 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 code?

Need more information on how to fix the P0620 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0620 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P0620 BMW — Generator Control Circuit Malfunction
P0620 Buick — Generator Control Circuit Malfunction
P0620 Cadillac — Generator Control Circuit Malfunction
P0620 Chevrolet — Generator Control Circuit Malfunction
P0620 Ford — Generator Control Circuit
P0620 GMC — Generator Performance Condition
P0620 Mazda — Generator Control Circuit Line Circuit
P0620 Mercedes-Benz — Generator Control Circuit Malfunction
P0620 Pontiac — Generator Control Circuit Malfunction
P0620 Saturn — Generator Control Circuit Malfunction

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about P0620 Code

1. What are common symptoms of OBDII code P0620 (Generator Control Circuit Malfunction)?

- Common symptoms include dimming or flickering lights, battery draining quickly, and irregular charging of the battery.

2. What are the possible causes of code P0620?

- The code P0620 can be caused by a faulty generator (alternator), problems with the generator control module, damaged wiring, or a weak battery.

3. How can I diagnose the cause of OBDII code P0620?

- To diagnose the cause of P0620, you can use a scan tool to check for any other related trouble codes, perform a visual inspection of the generator and wiring, and test the battery and charging system.

4. Can I still drive my vehicle with code P0620?

- It is not recommended to drive your vehicle with code P0620, as it can lead to a dead battery or other electrical issues while on the road.

5. How can I repair OBDII code P0620?

- Repairing code P0620 may involve replacing the generator, repairing or replacing the generator control module, fixing damaged wiring, or replacing the battery.

6. What are some tips for preventing OBDII code P0620?

- To prevent code P0620, regularly check your vehicle's charging system, maintain the battery in good condition, and address any electrical issues promptly.

7. Can a DIY enthusiast fix OBDII code P0620?

- Depending on the cause of the code, DIY enthusiasts with automotive repair experience may be able to fix P0620 by following proper diagnostic procedures and repair instructions.

8. How much does it cost to repair OBDII code P0620?

- The cost of repairing code P0620 can vary depending on the cause of the issue, parts needed for repair, and labor costs. It is recommended to get a professional diagnosis for an accurate estimate.

9. Will resetting the fault codes make OBDII code P0620 disappear?

- Resetting the fault codes may temporarily clear the P0620 code, but it will likely return if the underlying issue is not addressed and repaired.

10. Is OBDII code P0620 a serious problem?

- OBDII code P0620 should be taken seriously as it can lead to battery failure, electrical system issues, and potential stalling of the vehicle. It is advisable to address this code promptly.