What it means
The control circuit of camshaft profile actuator B on the exhaust side of bank 1 reports a control circuit low condition. Cam profile B (high-lift or VTEC-style) cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
- The engine or gearbox may go into limp mode
How it works
Actuator B switches the exhaust cam on bank 1 to its alternate, higher-lift profile. The control module monitors that circuit and sets P2B3A when the signal is too low, consistent with a control wire shorted to ground, a shorted coil, or resistance at a corroded connector.
Common causes
Most likely first.
- Control wire shorted to ground
- Internal short in actuator coil
- Connector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Power loss especially in mid-rpm range
- Possible rough idle or stalling
- Increased fuel consumption
How to diagnose it
- Save freeze-frame data and check live data for the bank 1 exhaust profile command and any related actuator codes.
- Inspect actuator B's bank 1 exhaust connector and harness for corrosion, rubbed insulation, or contact with ground.
- Check the connector terminals for corrosion or looseness that could raise contact resistance.
- With the circuit isolated according to the manufacturer's procedure, test the control wire for a short to ground.
- Measure actuator B's coil against the manufacturer's specification and continue with the circuit test procedure to pinpoint the low signal.
Common fixes
- Clean and secure corroded or loose terminals at the bank 1 exhaust actuator B connector.
- Repair wiring shorted to ground or damaged insulation near the actuator.
- Replace actuator B if its coil is internally shorted.
- Repair a faulty module connection if circuit tests identify one.
Can I keep driving?
Avoid hard acceleration and extended driving if power is reduced; the bank 1 exhaust cam may not switch to its alternate profile and the engine may run roughly or stall. Stop driving if stalling occurs.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.