P2650 "B" Rocker Arm Actuator Control Circuit/Open (Bank 1)

Some engines split rocker arm switching into two stages or groups, each fed by its own oil control solenoid; the second one is called actuator B. P2650 is logged when the engine controller finds the drive line of that B solenoid on bank 1 open, so switching the output on or off brings no matching electrical response. No carmaker publishes this code with limits. GM's 2015 four-cylinder table 15OBDG05 shows how the equivalent test for actuator A is built: a driver check that only runs above 11 V and fails after 100 bad readings out of 120. CARB requires such circuit checks for every output of a valve lift system. Shorts on the same line are reported as P2653 (ground) and P2654 (power). Until repaired, the stage served by solenoid B remains in its rest position.

Likely causes

Symptoms

• Check engine light on
• Second switching stage never engages, less power or economy in that range
• Possibly no other noticeable change in driving

Repair estimate

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

Related codes

References: law.cornell.edu, gsi.ext.gm.com, en.wikipedia.org.