P0020 is a rarely seen OBD II trouble code that can affect the Hummer H2. It’s a variable valve timing (VVT) related code, indicating a wiring issue with the bank 2 camshaft actuator “A.”
P0020 is often by low or sludgy oil. Check your H2’s oil as soon as possible.
P0020 is a generic code, meaning it has the same definition regardless of the make or model of the vehicle (including the H2).
Hummer H2 P0020 Quick Info
| Definition | P0020 “A” Camshaft Position Actuator – Circuit – Bank 2 |
| Symptoms | Stalling, Rought Idle, MIL Light |
| Common Causes | Wiring Issues, Bad Camshaft Actuator, Oiling Issues |
| Breakdown Risk | Not Usually, We Don’t Recommend Driving With P0020 |
| Repair Cost (Parts Only) | $40-$100 (Camshaft Actuator) |
Hummer H2 P0020 Defined: “A” Camshaft Position Actuator – Circuit – Bank 2
The Hummer H2 utilizes camshaft actuators to change the valve lift depending on the speed of the motor. This allows for a more efficient cam profile (better power and fuel economy).
Camshaft Position Actuator
Camshaft Position Actuators can change the lift of a camshaft up to 25 degrees. They are hydraulic, which means that they use the vehicle’s engine oil to control lift. So, if you have low oil pressure or dirty oil, it can keep them from doing their job correctly and trigger P0020.
When these camshaft actuators go bad, the engine will no longer be able to change the valve timing properly, and there may be a noticeable loss of fuel economy and power.
Circuit
The voltage value coming from the camshaft position actuator at Bank 2 is outside its normal operating parameters.
Bank 2
Bank two is the side of the engine with the second cylinder.
Since your H2 has a “V” engine with two cylinder heads, you’ll need to look up which side is bank 2. It’s usually the cylinder head further from the front of the engine.
Hummer H2 P0020 Symptoms
When a camshaft actuator goes bad, it can leave the engine timing a wreck. Here are some of the typical symptoms of P0020 in the Hummer H2:
- Poor Idle Quality– If the camshaft actuator fails while giving the engine aggressive valve timing, it’ll idle roughly.
- Decreased Gas Mileage– Now the engine can no longer adjust its cam timing on the fly, it will no longer be able to produce optimum combustion, which equals poor economy.
- Lost Power– The 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.
Hummer H2 P0020 Causes
The two main causes of P0020 in the Hummer H2 are issues with the wiring to the camshaft actuator or an issue with the actuator itself.
Oiling Issues
- Low Oil: The most common cause of P0020 is low oil. It needs to be low enough to lower the engine’s oil pressure (which is really low). You’ll likely get P0010 with an oiling issue too.
- 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 or Sludge Buildup (Too Thick or Too Thin): If you recently had an oil change and your H2 now has this code, change the oil again, and verify that the shop used the right oil.
Wiring Problems
The wiring from the solenoid to the ECM can become damaged or broken. This will throw the P0020 OBDII code. The wiring harness to the intake camshaft position sensor may also develop a poor connection.
If you’re new to chasing down electrical issues, P0020 is a great code to start learning on. The wiring is simple, and the YouTube: How to Find an Open or Short the Fast Easy Way.
Bad Intake Camshaft Position Actuator Solenoid
Here’s a phenomenal video on how to test a cam/crank actuator. It’s worth watching if you’re going to fix P0020 in your H2. Always make sure that you check everything else that you can before actually opening up an engine.
The cam 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 P0020 to appear.
Other Causes
- Engine Timing– If the 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 P0020 even though it’s not the actuator’s fault. Here’s more on that from this site: Timing Chain Jumped Symptoms and Diagnosis. Move timing higher on your list of possibilities if you are getting P0010 at the same time.
- Bad ECM (highly unlikely)- If your H2’s computer 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.
Final Thoughts
P0020 in the Hummer H2 is usually caused by a bad camshaft actuator or wiring issue. But you should check your oil before doing anything else. If it’s excessively dirty, the sludge buildup can cause P0020. Good luck!