Broken or corroded wiring to the changeover valve 2 solenoid; Failed changeover valve 2 solenoid (open coil); Loose or disconnected electrical connector at the valve; Damaged pins in the valve connector or ECM connector; Open circuit in the shared power or ground circuit for the changeover valves; Intake manifold flap mechanism seized, overloading the valve and causing a circuit fault

DTC codes / Volkswagen codes / P1520

P1520 · VolkswagenIntake Manifold Changeover Valve 2 Circuit Open

Q: What does code P1520 mean?

Intake Manifold Changeover Valve 2 Circuit Open. P1520 on Volkswagen vehicles means the engine control module (ECM) has detected an open circuit in the wiring for the intake manifold changeover valve 2, which is the solenoid that controls the second runner flap in the intake manifold. The ECM commands the valve to move and monitors the electrical circuit; when it sees no current flow or an unexpected voltage, it sets this code and may disable the changeover function.

P1520 on Volkswagen vehicles means the engine control module (ECM) has detected an open circuit in the wiring for the intake manifold changeover valve 2, which is the solenoid that controls the second runner flap in the intake manifold. The ECM commands the valve to move and monitors the electrical circuit; when it sees no current flow or an unexpected voltage, it sets this code and may disable the changeover function.

SystemPowertrain

Code typeVolkswagen specific

SeverityLow

Fix difficultyIntermediate

AreaVehicle speed, idle control and auxiliary inputs

Symptoms you may notice

Illuminated check engine light, often with no other symptoms
Slight loss of low-end torque or hesitation during acceleration
Rough idle or unstable engine speed when cold
Reduced fuel economy in some cases
In rare instances, a faint clicking or buzzing from the intake area if the valve is stuck

Common causes, most likely first

Broken or corroded wiring to the changeover valve 2 solenoid
Failed changeover valve 2 solenoid (open coil)
Loose or disconnected electrical connector at the valve
Damaged pins in the valve connector or ECM connector
Open circuit in the shared power or ground circuit for the changeover valves
Intake manifold flap mechanism seized, overloading the valve and causing a circuit fault

How to diagnose and fix it

Clear the code and test-drive to confirm it returns; note any freeze-frame data
Visually inspect the changeover valve 2 connector and wiring for damage or corrosion
Measure resistance across the valve solenoid terminals and compare to specification
Check for battery voltage and ground at the valve connector with the key on
Continuity-test the wiring between the valve and the ECM, repairing any open or short
If the circuit is intact, command the valve with a scan tool and listen for actuation
Replace the changeover valve 2 solenoid if it fails electrical or functional tests, then clear codes and verify

What the changeover valve code hides

A seized intake manifold flap can burn out the changeover valve solenoid, so always check that the flap moves freely before replacing the valve.
The changeover valve 2 circuit often shares a power or ground path with other solenoids, so a single corroded splice can set multiple codes including P1520.
Some technicians replace the valve only to find the connector pins have been pushed back, creating an open circuit that looks like a failed solenoid.
This code can be stored intermittently by a momentary loss of connection over bumps, so a wiggle test of the harness while monitoring live data is essential.
On certain Volkswagen engines, the changeover valve 2 is buried under the intake manifold, making a simple resistance check a labor-intensive job that should be planned carefully.

Can I keep driving with P1520?

You can usually continue driving with this code because it mainly affects intake tuning and does not cause a breakdown risk. Avoid heavy acceleration or towing until repaired, as the engine may feel less responsive and fuel economy could suffer.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

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