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.
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 1 is the side of the engine with cylinder 1. Inline engines only have this bank.
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
Most 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
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 P2645 means
- P: Powertrain: engine and transmission
- 2: Generic code: same on every make
- 6: Control modules and outputs
- 45: Specific fault in that system
Frequently asked questions
Can I keep driving with code P2645?
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 P2645?
The most common causes are: open coil in the rocker arm oil control solenoid; loose, corroded or oil-soaked solenoid connector; broken wire in the control or supply line.
Related codes
- P2648"A" Rocker Arm Actuator Control Circuit Low (Bank 1)
- P2649"A" Rocker Arm Actuator Control Circuit High (Bank 1)
- P2646"A" Rocker Arm Actuator System Performance/Stuck Off (Bank 1)
- P2655"A" Rocker Arm Actuator Control Circuit/Open (Bank 2)
- P2650"B" Rocker Arm Actuator Control Circuit/Open (Bank 1)
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.