GMC Sierra Fault Codes

About the Sierra

The GMC Sierra is a series of small, light-duty, and heavy-duty pickup trucks that first debuted in 1999, alongside its corporate cousin, the Chevrolet Silverado. There have been a total of four generations to be released, with the fourth and latest generation hitting the market in 2019.

The series ranges from the smallest Sierra 1500 and goes up to the heavy-duty 6500 HD.

The Sierra is nearly identical to its corporate cousin as it is essentially a rebadged version of the Silverado. It is also often compared to popular models from Ford’s F-150, the Dodge RAM, Nissan Titan, and Toyota Tundra.

In the two-plus decades that the model has been on the market, one of the most common issues it has faced is P0496. This code indicates that there is a high purge flow condition in the EVAP system.

One of the most common causes is a faulty or loose gas cap. This can be fixed by replacing or fastening the gas cap.

Another fault code that the model is known to suffer from is P0017. This serious code indicates that there is a correlation error between the signals from the exhaust camshaft position sensor in the first bank of the engine and the crankshaft position sensor.

One of the first steps for this code is checking that both position sensors are working properly. A faulty timing chain is another likely cause. However, old and dirty oil can also lead to this type of issue.

Another timing issue that the Sierra is known for is P0014, which indicates that the exhaust camshaft is too far ahead in its timing sequence.

This code can be a result of similar causes as the previous code. Other components to be known causes include a faulty camshaft variable timing solenoid and camshaft phaser.