Failed DISA valve actuator (internal solenoid or motor open circuit).; Damaged or corroded wiring harness connector at the DISA valve.; Broken or chafed wire in the control circuit between the DME and DISA valve.; Short to ground in the control circuit, often due to insulation damage.; Faulty engine control module (DME) driver, though this is less common.; Poor electrical connection at the DME connector pins.; Aftermarket or incorrectly installed DISA valve with incompatible electrical characteristics.

DTC codes / BMW codes / P1512

P1512 · BMWDISA Control Circuit Signal Low

Q: What does code P1512 mean?

DISA Control Circuit Signal Low. P1512 on a BMW indicates that the engine control module (DME) has detected a low signal on the control circuit for the DISA (Dual Intake System Adjuster) valve, which manages intake runner length for optimal torque and power. The DME commands the DISA actuator to change position, but the feedback voltage or current on the control wire remains below the expected threshold, suggesting an open circuit, short to ground, or a failed actuator.

P1512 on a BMW indicates that the engine control module (DME) has detected a low signal on the control circuit for the DISA (Dual Intake System Adjuster) valve, which manages intake runner length for optimal torque and power. The DME commands the DISA actuator to change position, but the feedback voltage or current on the control wire remains below the expected threshold, suggesting an open circuit, short to ground, or a failed actuator.

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.
A noticeable flat spot or hesitation during acceleration, especially at lower engine speeds.
Reduced engine power and torque, particularly in the mid-range RPM band.
Rough idle or unstable engine operation in some cases.
Poor fuel economy due to incorrect intake tuning.
In rare instances, a rattling noise from the intake manifold area if the DISA valve is mechanically stuck.

Common causes, most likely first

Failed DISA valve actuator (internal solenoid or motor open circuit).
Damaged or corroded wiring harness connector at the DISA valve.
Broken or chafed wire in the control circuit between the DME and DISA valve.
Short to ground in the control circuit, often due to insulation damage.
Faulty engine control module (DME) driver, though this is less common.
Poor electrical connection at the DME connector pins.
Aftermarket or incorrectly installed DISA valve with incompatible electrical characteristics.

How to diagnose and fix it

Perform a visual inspection of the DISA valve connector and wiring for corrosion, damage, or loose pins.
Use a scan tool to command the DISA valve on and off while listening for actuator operation and checking for a change in intake note.
Measure resistance across the DISA valve actuator terminals and compare to BMW specifications; an open circuit indicates a failed valve.
Check for continuity and short to ground on the control wire between the DISA valve and the DME connector.
Inspect the DME connector pins for corrosion or damage, and verify the control signal with a oscilloscope if possible.
If wiring and connector are good, replace the DISA valve with a genuine BMW part and clear the fault code.
After repair, clear adaptations and perform a road test to confirm the code does not return.

DISA valve diagnostics beyond the code

A low signal code often results from a simple unplugged or loose connector at the DISA valve, so always check connector seating before condemning the valve.
The DISA valve on BMW inline-six engines is prone to internal mechanical failure where the flap sticks, but the electrical actuator may still test good; a functional test with a scan tool is essential.
Wiring harness damage near the intake manifold is common due to heat and vibration, so inspect the loom carefully even if the connector looks fine.
This code can be set by a momentary glitch, so after clearing it, drive the car through a full drive cycle to see if it returns before replacing parts.
On some BMW models, a faulty DISA valve can cause a whistle or rattle that misleads diagnosis toward a vacuum leak; verify the actuator operation first.

Can I keep driving with P1512?

You can generally continue driving with this code, but avoid aggressive acceleration and heavy load until repaired, as the engine may lack power and fuel economy will suffer. Prolonged driving with a failed DISA valve is not dangerous, but it can lead to carbon buildup and reduced performance over time.

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.