Broken or chafed wire in the actuator harness, commonly at the connector or where the loom bends near the cylinder head; Corroded or loose electrical connector at the bank 2 camshaft position actuator solenoid; Failed camshaft position actuator solenoid with an open internal coil; Blown fuse or damaged relay supplying power to the actuator circuit; Engine control module (DME) driver circuit failure, though this is rare; Oil sludge or debris blocking the actuator, causing the solenoid to overheat and fail open

DTC codes / BMW codes / P1581

P1581 · BMWB Camshaft Position Actuator Control Open Circuit Bank 2

Q: What does code P1581 mean?

B Camshaft Position Actuator Control Open Circuit Bank 2. P1581 on BMW vehicles means the engine control module (DME) has detected an open circuit in the electrical path for the bank 2 B camshaft position actuator, which is the solenoid that adjusts camshaft timing on the second bank of cylinders. The computer commands the actuator but sees no current flow or an unexpected voltage return, so it flags the circuit as open and typically disables variable cam timing for that bank.

P1581 on BMW vehicles means the engine control module (DME) has detected an open circuit in the electrical path for the bank 2 B camshaft position actuator, which is the solenoid that adjusts camshaft timing on the second bank of cylinders. The computer commands the actuator but sees no current flow or an unexpected voltage return, so it flags the circuit as open and typically disables variable cam timing for that bank.

SystemPowertrain

Code typeBMW specific

SeverityMedium

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

Illumination of the check engine light, often with no other noticeable symptoms
Rough idle or unstable engine operation, especially when cold
Reduced engine power and poor acceleration due to disabled camshaft timing
Increased fuel consumption and higher emissions
Occasional stalling or hesitation during light throttle
A noticeable loss of low-end torque on V8 and V12 engines with bank 2

Common causes, most likely first

Broken or chafed wire in the actuator harness, commonly at the connector or where the loom bends near the cylinder head
Corroded or loose electrical connector at the bank 2 camshaft position actuator solenoid
Failed camshaft position actuator solenoid with an open internal coil
Blown fuse or damaged relay supplying power to the actuator circuit
Engine control module (DME) driver circuit failure, though this is rare
Oil sludge or debris blocking the actuator, causing the solenoid to overheat and fail open

How to diagnose and fix it

Clear the code and verify it returns; check for any related camshaft position sensor codes that may point to a different root cause
Inspect the bank 2 camshaft actuator connector and harness for corrosion, loose pins, or chafed wires, and repair as needed
Measure resistance across the actuator solenoid terminals and compare to BMW specifications; an open reading confirms a failed solenoid
Check for battery voltage at the actuator connector with the key on and the circuit loaded; a missing supply points to a fuse or wiring fault
Test the control wire from the DME to the actuator for continuity and short-to-ground; repair any open or shorted section
If wiring and solenoid test good, substitute a known-good actuator and recheck; replace the actuator if the code clears
As a last step, diagnose the DME driver circuit or replace the DME only after all other causes are ruled out

What a P1581 open circuit really means

A P1581 is almost always an electrical open, not a mechanical timing fault, so replacing camshafts or timing chains before checking the solenoid circuit wastes money.
On many BMW V8 and V12 engines, the bank 2 actuator connector sits close to the exhaust manifold and suffers heat damage that cracks the insulation and causes an intermittent open.
The same open circuit can set a companion camshaft position sensor code, leading some technicians to replace the sensor when the actuator wiring is the real culprit.
Oil sludge from extended oil change intervals can seize the actuator spool, burning out the solenoid coil and creating the open circuit that sets P1581.
A faulty DME driver is often blamed prematurely; always load-test the circuit and confirm the solenoid resistance before condemning the control module.

Can I keep driving with P1581?

You can usually drive the car with P1581 because the engine defaults to a fixed cam timing strategy, but avoid heavy acceleration and long trips until the circuit is repaired. Continued driving with a disabled actuator can increase fuel consumption and emissions, and if the engine runs rough enough to misfire, stop driving to prevent catalytic converter damage.

Tools that help

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Guidance is general and written for BMW vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.