P0121 is a somewhat common trouble code with the GMC Sierra. It’s an OBDII code and has to do with the Throttle Pedal Position Sensor. It is relatively serious problem since it leaves your vehicle in failsafe mode. P0121: Throttle Pedal Position Sensor → Switch (TPS) A Circuit Range → Performance Problem OBDII code P0121 … Read more
If your GMC Sierra has the P0303 trouble code, you should know that it’s about as common of a code as there is. It’s a generic code (same meaning for all vehicles) that indicates that your truck’s third cylinder is misfiring. P0303 is a real drivability concern and should be dealt with right away. If … Read more
P0302 in the GMC Sierra is a common OBD II trouble code. It indicates that your truck’s second cylinder has a misfire. P0302 is a real drivability concern and should be dealt with right away. If it’s bad enough to cause your Sierra’s check engine light to come on, you shouldn’t drive your truck at … Read more
A very common issue with the GMC Sierra is the P0449 code. This trouble code is a reference number that is given to you when you plug your Sierra into a OBDII scanner. P0449 deals with the evaporative emissions control system. It often appears with, or is related other codes, such as P0420, P0446, and … Read more
P0300 is a generic OBDII code that can occur with the GMC Sierra. This code indicates that your truck’s engine is misfiring and can be a drivability threat. P0300 is often accompanied by cylinder-specific misfire codes (P030X, where the X indicates the cylinder number that is misfiring). If you have P0300 and a cylinder-specific misfire, … Read more
P0455 in the GMC Sierra is a trouble code that indicates your truck has a LARGE evaporative emissions leak. With this code, you shouldn’t notice any symptoms besides perhaps a noticeable fuel smell. P0455 usually is not an immediate threat to the driveability of your Sierra. But, whenever the check engine light is on, it’s … Read more
A prevalent issue with the GMC Sierra is the P0446 code. This code corresponds to a specific number obtained when connecting your Sierra to an OBDII scanner. A faulty vent control valve most commonly causes P0446. Definition P0446: EVAP System – Vent Control Circuit – Malfunction Symptoms Usually none Common Causes Bad EVAP Vent Control … Read more
The P0440 code is a common trouble code that many GMC Sierra owners may encounter. It indicates that there is an issue with the truck’s Evaporative Emission Control (EVAP) system. Specifically, the EVAP system is malfunctioning. A variety of causes can trigger the P0440 code, with the most common one being a loose or damaged … Read more
One of the most common trouble codes with the GMC Sierra is the P0496 code. This code number references a number that is given to you when you plug your Sierra into an OBDII scanner. GMC Sierra P0496 Symptoms P0496 code in the GMC Sierra will often be accompanied by an erratic idle. The engine … Read more
P0171 and P0174 both indicate that there is a lean condition present in your GMC Sierra. By themselves, these are some of the most common OBD2 codes. When they are together, it indicates that the entire engine is running lean. Definition Both of these codes are generic, which means they have the same meaning … Read more