Pin16

P2656

"A" Rocker Arm Actuator System Performance or Stuck Off (Bank 2)

Severity
High
Driving
Short journeys only

The "A" rocker arm actuator on bank 2 is electrically sound but the rockers are not switching as commanded - stuck in their default state. On a high-mileage engine this usually means oil pressure is not reaching the mechanism, or the switching rocker itself is failing.

Possible causes

What you might notice

What to check, in order

  1. Do not keep driving on a persistent misfire. Unburnt fuel reaching the catalytic converter destroys it, and a failing switching rocker can wear the camshaft lobe it runs against.
  2. Check the engine oil level, condition and viscosity first. These actuators are driven by oil pressure through small solenoid valves, so oil that is low, degraded or the wrong grade causes more faults here than wiring ever does.
  3. Ask when the oil was last changed. Extended or missed oil changes are the biggest single cause of failures in oil-actuated valve systems.
  4. Listen for a tick from the top of the engine, which points at the rocker mechanism rather than the solenoid.
  5. Inspect the connector for oil contamination and corrosion.
  6. Measure the solenoid winding resistance against specification.
  7. Read all codes - misfire codes alongside these identify which cylinders are affected.

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Where this code sits