Powertrain, generic (extended)

P2653 "B" Rocker Arm Actuator Control Circuit Low (Bank 1)

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2653 points to a voltage that is too low on the control line of rocker arm solenoid B, bank 1. On a solenoid switched from the supply side, a line rubbing against the engine block or a shorted coil pulls the signal down while the output is active; the controller's driver then reports an overcurrent or a low-voltage state. No manufacturer documents this code publicly. For actuator A, GM's 15OBDG05 runs the same kind of driver diagnosis on its 2015 four-cylinders above 11 V, with a fault after 100 of 120 samples and the MIL on at once. CARB treats such shorts as circuit faults that every lift system output must detect. Many drivers shut down to protect themselves, so the B stage drops out. P2650 covers an open, P2654 a short to power.

Likely causes

Control wire of solenoid B shorted to engine ground
Shorted turns inside the solenoid B coil
Engine oil inside the connector creating a leakage path

Symptoms

  • MIL on soon after the fault appears
  • B stage switched off, reduced power or economy

Repair estimate

DifficultyMediumDIY possible
Parts and labour€50–450
Time0.5–2.5 h

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

Parts involved

rocker arm actuator b b1oil control valvewiring harness

Related codes

P2650P2654P2648P2663

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