For bank 2, P2656 reports that actuator A was told to switch the rocker arms but the expected change in valve lift did not show up, or it was too small. Since such engines give every bank a separate oil feed and solenoid, a clogged screen or sticking spool on that side alone is enough. No manufacturer publishes P2656; GM's bank 1 test (P2646 in 15OBDG05) shows the usual method: an intrusive lift toggle at moderate load and warm oil, judged by oil-pressure ripple. CARB permits two-step systems to flag faults only once emissions exceed the threshold, but every such failure must then be caught. Low oil level, wrong viscosity and sludge deserve the first look.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Bank 2 is the side without cylinder 1, so it only exists on V or boxer engines.
Symptoms
- MIL on after a completed test
- Weaker response at higher engine speed
- Higher fuel consumption
Most likely causes
- Low, wrong or sludged engine oil
- Clogged oil screen or sticking spool at the bank 2 solenoid
- Seized locking pin in a bank 2 rocker arm
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P2656 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 6: Control modules and outputs
- 56: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2656?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P2656?
The most common causes are: low, wrong or sludged engine oil; clogged oil screen or sticking spool at the bank 2 solenoid; seized locking pin in a bank 2 rocker arm.
Related codes
- P2657"A" Rocker Arm Actuator System Stuck On (Bank 2)
- P2655"A" Rocker Arm Actuator Control Circuit/Open (Bank 2)
- P2646"A" Rocker Arm Actuator System Performance/Stuck Off (Bank 1)
- P2661"B" Rocker Arm Actuator System Performance/Stuck Off (Bank 2)
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.