PCM uses the generator turn on signal circuit to control the generator. A high-side driver within the PCM allows PCM to turn generator on and off. When generator operation is desired, PCM sends a 5-volt signal to voltage regulator via the generator turn on signal circuit. This causes the voltage regulator to begin controlling generator field circuit. Once generator is enabled by PCM, voltage regulator controls generator output independently of the PCM. Under certain operating conditions, PCM can turn off the generator by turning off the 5-volt signal on the generator turn on signal circuit. The PCM has fault detection circuitry which monitors the state of the generator turn on signal circuit. If fault detection circuit senses a voltage other than what is expected, this DTC will set. The voltage regulator also contains fault detection circuitry. If regulator detects a problem, regulator will ground the generator turn on signal circuit, pulling the voltage low, causing PCM to set DTC.

When this DTC sets, PCM sends a class 2 serial data message to the IPC, illuminating the CHARGE indicator light.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

DTC P0620: Generator Performance: Description

Use the Manual With the Right Hardware

When to See a Mechanic