P0620 OBD Error Code: Problem & Solutions

OBD Code P0620 - Generator Control Circuit Malfunction

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Error code P0620? Too complicated to crack? Not anymore! Here’s Parts Avatar’ easy guide that’s going to help you smoothly crack the code P0620. This generic powertrain code signals at fault detected in the generator control circuit. The PCM or one of the other supporting control modules are in charge of detecting the fault and so they consequently detect the fault. These control modules widely range from the alternative fuel control module, the body control module, the anti-lock brake control module, the instrument panel control module, the fuel injection control module, the turbo control module, the anti-theft module, the cruise control module, the traction control module, proximity alert module, and the climate control module etc. (but are not limited to these).

Learn More About OBD Error Code P0620

The PCM plays the role of monitoring the vehicle’s generator through a generator turn-on signal circuit, permitting it to turn the generator off and on. When the generator needs to be turned on, the PCM directs a five-volt signal with the help of the generator turn-on signal circuit to the voltage regulator. As it does so, it allows the voltage regulator to start monitor the generator field circuit. When the generator is turned on and it starts functioning, the voltage regulator can start controlling the generator output independent of the PCM. During some of the operating conditions, the PCM can turn off the five-volt signal therefore turning off the generator too.


The PCM is also equipped with fault-detection circuitry to control these operations. If any unusual voltage or any other problem is detected, it cuts or reduces the power. And, it is only then it stores the code P0620.


What causes this problem with the Generator Control Circuit Malfunction?


  • A possible fault in the PCM
  • A PCM programming error
  • The generator control circuit open or shorted
  • A failure in the general assembly
  • Inadequate control module ground

Replace/Repair These Parts To Fix OBD Code P0620

  1. PCM - A distorted Powertrain control module can end up being the chief host inviting the Error Code P0620. So, replacing one can be one of the wisest decisions to avoid a problematic system. Get yours now at your doorstep with Parts Avatar. Tune in now.
  2. Battery - Facing the error code P0620? A bad quality or damaged Battery can always be disastrous for the system also it is one of the primal causes behind the occurring of the error code P0620. Log into Parts Avatar for superior quality Batteries at pocket friendly prices.
  3. Alternator - Having problems with the Alternator? Don’t you worry, Parts Avatar has it all. A defective Alternator could end up being the root cause behind the error code P0620.
  4. Automatic Transmission Module - Get your error code fixed instantly with this new automatic transmission module available at Parts Avatar. So? Get yours now.

Symptoms Of OBD Error Code P0620

It is essential to know the symptoms of an issue as only then you would be able to solve the problem. So that’s why we have listed out some major symptoms of OBD Code P0620 here:


Common Symptoms


Sometimes, the symptoms may contain a discharged battery, issues with the drivability, harsh shifting, decreased fuel economy, the engine may not work or run rough at idle, declining or bad acceleration, a stored trouble code, and probably an illuminated service engine soon lamp. If this code sets up, and you don’t see a service engine soon lamp illuminated, the code appears as pending.


  • Complications with the engine drivability
  • Engine halting while idling
  • At times, delayed engine cranking (particularly when cold)
  • Other various codes stored

How To Correct P0620 Generator Control Circuit Malfunction

Here are some ways with the help of which you will be able to correct the OBD Code P0620


  • All the wires or other electronic parts functioning out of order should be replaced
  • The technician is required to investigate the vehicle, including testing the unsound and stalled electronic parts. It is essential for the technician to perform a voltage test on an number of parts, along with testing both the battery and alternator. The technician is required to narrow down the range of viable issues, and then advice you on your next step while treating and performing the diagnosis
  • The generator should be restored or mended
  • Change or repair the PCM

There is no need to be anxious as Parts Avatar – Car Parts Online is here to help you out! We have high grade PCM, battery, alternator, fuel control module, body control module, fuel rims, battery connectors, shift solenoid, fuel cleaner, transmission sensor and a lot more for our precious customers.

Easy Diagnosis Of Engine Error OBD Code P0620

Here are some steps which you should follow in order to diagnose this P0620 fault code:


Using an OBD-II scanner the technician should check the trouble codes the vehicle has stored. Next, the generator needs to be checked for any signs of any poor connection or defect that may have led to a misread of the voltage. All the multiple circuits linked with the generator should be inspected too. All the wires associated with this component along with the connectors should also be inspected and tested. If everything else is checked out and tested, next the technician needs to check the PCM to ensure it didn’t store the code incorrectly.


Common Mistakes When Diagnosing the P0620 Code


To accurately diagnose this problem can often be a tedious task, which is why it is imperative that the technician should not directly conclude assuming the PCM to be at fault. So, in order to ensure an exact diagnosis and to check whether if the fault lies in the PCM or not, the vehicle should be test driven and all the codes should be cleared to see if returns back.

Other Diagnostic Codes Related To OBD Code P0620

P0621 - Generator Lamp "L" Control Circuit Malfunction

P0622 - Generator Field "F" Control Circuit Malfunction

P0623 - Generator Lamp Control Circuit