P2648"A" Rocker Arm Actuator Control Circuit Low (Bank 1)
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2648 points to a low-side electrical fault on the control line of rocker arm actuator A, bank 1: the line reads low, typically a short to ground or a solenoid with shorted turns. GM's 2015 table 15OBDG05 tests the driver for short-to-ground faults with ignition in crank or run and more than 11 V, trips after 100 bad samples out of 120 and lights the MIL at once (Type A). In GM's 2004 table for the Honda-made L66 V6 of 3.5 litres, the controller expects a return signal whenever it energises the VTEC solenoid; 0 V for 2 s sets the code. Check for chafed wiring against the head, a wet connector or a failed solenoid. Without switching the engine runs only in base lift.
- What you may notice
- MIL on immediately
- No switching to the second lift stage
- Reduced top-end power
- Likely causes
- LikelyControl wire chafed through to ground
- PossibleShorted turns in the solenoid winding
- RareMoisture or oil bridging pins in the connector
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €60 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.