P0621 - OBD II Trouble Code

Our automotive experts have put together the following information about the P0621 diagnostic trouble code. We've provided the common symptoms that occur when this code is set along with the frequent repairs that address the issues related to the P0621 code.

What Does P0621 Code Mean?

OBD-II Code P0621 is defined as a Generator Lamp/L Terminal Circuit

The Alternator recharges the Battery when the engine is running. The Alternator is controlled by the engine control module (PCM). If the PCM detects an incorrect signal from the Alternator, the PCM will set code P0621.

P0621 Symptoms

• Engine may not start
• Engine may stall

Common Problems That Trigger the P0621 Code

• Alternator failure
• Battery failure
• Powertrain Control Module (PCM) failure
• Wiring issue

Common Repairs Needed for the P0621 Code

• Alternator Replacement