P0671 is a somewhat rare diagnostic trouble code (But a common diesel one). It’s generic, so it has the same definition for the GMC Sierra as it would any other vehicle. P0671 is typically caused by a bad glow plug or wiring issue. We cover troubleshooting steps in detail below. P0671 Definition: First Cylinder Glow … Read more
P0688 is a relatively rare OBD2 trouble code. It’s a generic code, meaning that it has the same definition for any vehicle made for the 1996 model year and up. This includes the GMC Sierra. The most common causes of P0688 are a bad PCM power relay or a wiring issue between the PCM and … Read more
P0685 is a somewhat rare OBDII trouble code. It’s a general code, so it has the same meaning for the GMC Sierra as any other vehicle. It indicates that the circuit that provides power to the PCM is not functioning properly. Most of the time, P0685 will cause your Sierra not to start, which leaves … Read more
P0661 is a relatively rare OBD2 trouble code. It indicates that the electrical reading coming from your GMC Sierra’s intake manifold tuning valve control circuit (on the bank 1 side) is below its specified operating range. While P0661 is a generic code, so it has the same definition for all vehicles. P0661 Definition: Intake Manifold … Read more
P0660 is a somewhat common OBDII code. It’s generic, so it has the same meaning for the GMC Sierra as it would any other vehicle made for the 1996 model year and up. This code indicates that there is an issue with the bank 1 side of the intake manifold valve tuning control circuit. Common … Read more
P0627 is a somewhat rare and generic OBD2 trouble code, which means that it has the same meaning for the GMC Sierra as it would any vehicle made for the 1996 model year and up. In the Sierra, P0627 is most commonly caused by a wiring issue, bad fuel pump, or defective CAN bus. P0627 … Read more
P0621 is a generic OBD2 code, which means that it has the same meaning for the GMC Sierra as it would any other vehicle. However, it can be challenging to diagnose due to the necessity of removing the instrument cluster. OBD2 P0621 indicates an issue with the circuit that controls the generator lamp, which is … Read more
P0622 is a somewhat rare OBD2 trouble code. It’s a general code, meaning it has the same definition for the GMC Sierra as it would any other vehicle. This code indicates the generator field coil control circuit is malfunctioning. It can be a challenge to diagnose. P0622 Meaning: Generator Field F Control Circuit Malfunction “Generator … Read more
P0650 is a somewhat rare OBD2 trouble code. It is generic, meaning that it has the same definition for any vehicle, including the Toytoa Sierra Your Sierra’s PCM will set P0650 when it detects an issue with the malfunction indicator lamp (MIL), also commonly referred to as the check engine light. The biggest issue … Read more
P0607 is a general OBD2 diagnostic code, meaning it has the same meaning for the GMC Sierra as it would any other vehicle. It is not a very common code. P0607 is most commonly caused by a bad PCM/ECM, battery, or wiring to and from the PCM. P0607 Definition: Control Module – Performance P0607 has … Read more