P0011 is a common (and serious) OBD II diagnostic trouble code that can occur in the GMC Sierra. It indicates an issue with your truck’s Variable Valve Timing (VVT) system.
The first thing you should do when you have this code is check your Sierra’s oil. If the oil level is too low, the camshaft actuators won’t work properly.
P0011 Trouble Code: Quick Info
|Definition||P0011 “A” Camshaft Position Timing Over Advanced or System Performance (Bank 1)|
|Symptoms||Stalling, decreased MPG, rattling, engine running rough, check engine light|
|Common Causes||Low oil, wrong oil viscosity, faulty camshaft actuator, timing chain/belt jumped|
|Breakdown Risk||Not usually, but in rare cases, the underlying causes can damage the engine|
|Repair Cost (Parts Only)||Usually well under $200|
P0011 Definition: GMC Sierra
The technical definition of P0011 for the Sierra is “A” Camshaft Position Timing Over Advanced or System Performance (Bank 1). Here it is separated into its separate pieces, with a quick explanation of each.
Camshaft Position Timing
Camshaft position timing how your GMC Sierra’s intake and exhaust valves close relative to the location of the crankshaft. The camshaft’s position is constant relative to the crank’s position on vehicles that don’t have variable valve timing.
Vehicles with VVT can change camshaft position timing depending on whether you need power or economy.
Over Advanced or System Performance
VVT allows the engine to act as though it has different camshaft profiles at different RPMs; this is great for both power and fuel economy. Sometimes, the system will get stuck in an over-advanced position.
When this happens, your GMC Sierra will store trouble code P0011.
Valve timing control methods can be quite different for every engine, even from the same manufacturer, but the basics are the same.
Camshaft actuators or phasers change how long the intake and exhaust valves stay open. They are hydraulic, which means that they use the vehicle’s engine oil to change the intake valve timing.
Some simpler systems change the cam timing, while others change cam profiles entirely. Here’s a detailed write-up on exactly how VVT works if you’re interested in learning more.
Bank one is the side of the engine with the first cylinder. If your Sierra has an inline engine, you don’t need to concern yourself with this.
If your Sierra has a “V” engine with two cylinder heads, you’ll need to look up which side is bank 1. It’s usually the cylinder head closer to the front of the engine.
GMC Sierra P0011 Symptoms
When the cam timing is off, it can cause some issues with the motor. Here are some of the typical symptoms of P0011 in the GMC Sierra:
- Poor Idle Quality– If the camshaft actuator fails while it is too far advanced, it’ll idle roughly.
- Rattling Sound– You may hear the camshaft actuator rattling at idle speed since it’s not where it’s supposed to be. A rattling sound can also indicate the timing chain jumped a tooth.
- Decreased Gas Mileage– Now that your Sierra’s engine can no longer adjust its cam timing on the fly, it will no longer be able to produce optimum combustion, which causes poor economy.
- Lost Power– Your truck’s engine will not be able to produce as much power; this is because the cam profile will not allow it to run a performance power curve when you need more power.
- Service Engine Soon Light- Most of the time, you’ll be able to feel or see one of the above symptoms, but if you can’t, the service engine soon light will still come on and let you know something is wrong.
- Hard to Start– With the timing too far advanced, it won’t be easy to start the motor, especially when it is warm.
GMC Sierra P0011: Causes
Quite a few things can cause the P0011 code in your GMC Sierra. Sometimes the P0011 fix is as easy as topping off the oil.
Here are the most common causes, presented to you in order from the easiest thing to check to the most difficult:
The first thing you should do is check your Sierra’s oil. There are three ways that it can cause P0011:
- Low Oil: The most common cause of P0011 is low oil. It needs to be low enough to lower the engine’s oil pressure (which is really low).
- Dirty Oil: If the oil and/or oil filter haven’t been changed in a long time, sometimes it can cause the camshaft actuator to clog up with sludge.
- Wrong Viscocity (Too Thick or Too Thin): If you recently had an oil change and your Sierra now has this code, change the oil again, and verify that the shop used the right oil.
Bad Intake Camshaft Position Actuator or Actuator Solenoid
The actuator solenoid itself can go bad over time. You certainly don’t want to start here since, a lot of the time, it’ll be something else that causes the P0011 to appear. Here’s a good video that explains how to test the camshaft actuator using a scan tool:
If your Sierra’s camshaft(s) are no longer synced to the crank properly (such as if the timing chain jumped a tooth), it can cause the engine timing to be off enough to throw the P0011, even though it’s not the actuator’s fault. Here’s more on that from this site: Timing Chain Jumped Symptoms and Diagnosis
The wiring from the solenoid to the ECM can become damaged or broken, this will throw the P0011 OBDII code. The wiring harness to the intake camshaft position sensor may also develop a poor connection—YouTube: How to Find an Open or Short the Fast Easy Way.
Bad ECM (highly unlikely)
If your Sierra’s engine controller goes bad, it may throw this code along with other issues. Here’s how to tell if you have a bad ECM Autoblog: Symptoms of a Bad ECM.
If it has been a long time since you’ve changed your truck’s oil, or you find that there may be a reason to believe that the oil thickness is wrong, change the oil and see if that clears P0011 in your GMC Sierra. If it doesn’t, you’ll have to dive into the mechanical issue causing the code. Good luck!