P0620 - GENERATOR CONTROL CIRCUIT MALFUNCTION

The Keep Alive Memory (KAM) allows the vehicle’s control modules to store data related to the vehicle’s operation. The KAMA works even when the vehicle is off or the battery power is briefly interrupted. Once the ignition switch is turned on, power is delivered to the PCM. After that, a series of self-tests are performed on the controllers through the Controller Area Network (CAN). The signals from each module are compared. Also, the interaction between them is checked.

The DTC P0620 OBD2 is set because the PCM has detected the generator or alternator control circuit has experienced an error in its operation. The PCM supplies energy to the generator while the vehicle’s engine is running.

• Check Engine light ON.
• Limits when driving the vehicle
• The engine stops unexpectedly at idle.
• Delays in starting the engine, especially when the engine is cold.

The reasons for setting the P0620 OBDII diagnostic code are:

• The generator circuit may be shorted or open.
• Possibly the generator assembly is faulty.
• The ground signal to the control module may not be enough.
• The PCM may have a programming error.

To solve the P0620 OBD2 fault code, try this:

• Consult the TSBs to begin the diagnosis
• Check for other stored DTCs. Pay attention to those related to a control module power supply. If these codes are present, diagnose them before the P0620.
• Consult the vehicle's information source for wiring diagrams, diagnostic flow charts and connector face views. By using a multimeter, perform electrical checks on the various fuses and relays that deliver power to the controller. Make any necessary corrections.
• Inspect the wiring associated with the generator. If they have damage such as wear, corrosion, or burns, make the appropriate corrections.