P0021 on GMC
Intake Camshaft Position Timing - Over-Advanced (Bank 2)
P0021 on GMC vehicles indicates intake camshaft position timing - over-advanced (bank 2). Au7o has documented this code across 1 GMC model — most commonly on Sierra 1500. P0021 means the engine computer detected that the intake camshaft on bank 2 is timed too far advanced and won't return to its commanded position. Most modern engines use variable valve timing (VVT), where an oil-pressure-driven actuator rotates the camshaft to optimize power and efficiency; the PCM compares the camshaft's actual position to its target. When the cam stays over-advanced beyond an acceptable limit, this code sets. Bank 2 refers to the side of the engine that does not contain cylinder number one. You may notice rough idle, reduced performance, or lower fuel economy. Typical repair costs on GMC range from $40 to $450, depending on the specific model and root cause.
Common Causes of P0021
- •Dirty or low engine oil restricting the VVT system
- •Stuck or failed camshaft oil control valve (VVT solenoid) on bank 2
- •Clogged VVT solenoid screen or oil passage
- •Faulty camshaft position actuator / phaser
- •Wiring or connector fault at the VVT solenoid
- •Camshaft or crankshaft position sensor problems
- •Worn timing chain, guides, or stretched chain altering cam timing
P0021 on GMC by Model
GMC Sierra 1500(1 issue)
- P0011 — Intake Cam Over-Advanced from Sludge-Clogged VVT Solenoid on 5.3L V82007-2022
P0011 means the Bank 1 intake camshaft is timed more advanced than the ECM commanded — the phaser is stuck/biased advanced. On the Sierra 1500 5.3L/6.2L, the dominant cause is a VVT (camshaft actuator) solenoid whose internal screen has clogged with oil sludge or AFM debris, jamming the plunger so oil pressure to the phaser can't be modulated. GM acknowledges sticking/binding solenoids in PIs such as PIP5130K and PIP5855. Low or incorrect-viscosity oil is a very common trigger, so oil condition is always checked first. Because AFM lifter wear sheds metal into the oil, that debris circulates and clogs the solenoid screens — tying P0011 directly to the trucks' oil-consumption reputation. Drivers report rough running, and in worse cases stalling when slowing to a stop.
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View P0021 across all makes →Frequently Asked Questions
What does P0021 mean on GMC?▼
P0021 stands for "Intake Camshaft Position Timing - Over-Advanced (Bank 2)." P0021 means the engine computer detected that the intake camshaft on bank 2 is timed too far advanced and won't return to its commanded position. Most modern engines use variable valve timing (VVT), where an oil-pressure-driven actuator rotates the camshaft to optimize power and efficiency; the PCM compares the camshaft's actual position to its target. When the cam stays over-advanced beyond an acceptable limit, this code sets. Bank 2 refers to the side of the engine that does not contain cylinder number one. You may notice rough idle, reduced performance, or lower fuel economy. On GMC specifically, this code is documented across 1 model.
What causes P0021 on GMC vehicles?▼
Common causes on GMC: Dirty or low engine oil restricting the VVT system, Stuck or failed camshaft oil control valve (VVT solenoid) on bank 2, Clogged VVT solenoid screen or oil passage, Faulty camshaft position actuator / phaser, Wiring or connector fault at the VVT solenoid. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0021 on a GMC?▼
Repair costs on GMC range from $40 to $450, depending on the specific model and root cause.
Which GMC models have P0021 documented?▼
Au7o has documented P0021 on 1 GMC model: Sierra 1500.