What it means
The control circuit of camshaft profile actuator B on the exhaust side of bank 1 reports a control circuit high 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 controls the alternate, higher-lift profile of the exhaust cam on bank 1. The control module monitors the circuit and sets P2B3B when its signal is too high, which can result from a wire shorted to battery voltage, an open coil, or a poor connector contact.
Common causes
Most likely first.
- Control wire shorted to B+
- Open 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
- Record freeze-frame data and review live data for the bank 1 exhaust profile command and related circuit codes.
- Inspect actuator B's exhaust-side connector and harness for corrosion, loose pins, or chafing against a power feed.
- With the circuit isolated as the manufacturer specifies, test the control wire for a short to battery voltage.
- Measure the actuator coil against the manufacturer's specification, since an open coil can cause a high circuit reading.
- If the wire and coil pass, follow the manufacturer's circuit procedure to check connector continuity and the module connection.
Common fixes
- Secure the connector and repair corroded or loose terminals at bank 1 exhaust actuator B.
- Repair control wiring shorted to a power feed.
- Replace actuator B if its coil is open or out of specification.
- Repair a faulty module connection if testing confirms it.
Can I keep driving?
Drive gently and avoid high-load acceleration because the bank 1 exhaust cam may not change profiles, limiting power and affecting fuel economy. Stop if the engine stalls or runs too roughly to control safely.
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.