Powertrain, generic (extended)

P2645 "A" Rocker Arm Actuator Control Circuit/Open (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Engines that switch valve lift or deactivate cylinders through their rocker arms use an actuator, usually an oil control solenoid, to send oil to the locking pins. P2645 means the engine controller sees the drive circuit of actuator A on bank 1 as open: the state it commands and the state it reads back on the line disagree. GM's 2015 four-cylinder table 15OBDG05 runs this check wherever VVL hardware is fitted, needs more than 11 V, counts 100 failures within 120 samples taken every 250 ms and sets a Type A fault with the MIL on the first trip. P2648 and P2649 cover shorts to ground and to power. The engine stays in its default lift, so power at high revs or economy suffers.

Likely causes

Open coil in the rocker arm oil control solenoid
Loose, corroded or oil-soaked solenoid connector
Broken wire in the control or supply line
Faulty output driver in the engine control module

Symptoms

  • MIL on, often on the first trip
  • No change to high lift, weak pull at high engine speed
  • Cylinder deactivation or economy mode no longer engages

Repair estimate

DifficultyMediumDIY possible
Parts and labour€60–450
Time0.5–2 h

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

Parts involved

rocker arm actuator a b1oil control valvewiring harness

Related codes

P2648P2649P2646P2655P2650

References: gsi.ext.gm.com, law.cornell.edu.