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P1520

Intake Manifold Changeover Valve 2 Circuit Open.

  • Volkswagen
  • Powertrain
  • Manufacturer code
  • Low severity

How this code is built

P
SystemPowertrain
1
Defined byThe manufacturer
5
AreaVehicle speed, idle control and auxiliary inputs
20
FaultThe specific fault in that area

What it means

On Volkswagen group vehicles, P1520 means the engine control unit has detected an open circuit in the control circuit for intake manifold changeover valve 2. The control unit drives this valve (usually a solenoid that switches vacuum to the intake manifold flap or changeover actuator) and sees no current flow, indicating a break in the wiring, a bad connection or a failed solenoid coil. Which engines use this valve, and how it is laid out, depends on the model and engine.

Symptoms

  • Engine warning light on
  • Reduced power or a flat spot in a particular rev range
  • Poorer mid-range torque or top-end performance
  • Slightly higher fuel consumption
  • Rough or uneven running at some engine speeds in some cases

Possible causes

  • Faulty intake manifold changeover valve solenoid with an open internal coillikely
  • Corroded, loose or damaged electrical connector at the valvelikely
  • Broken, chafed or high-resistance wiring between the valve and the control unitpossible
  • Missing or open power supply or fuse feeding the valve circuitpossible
  • Pin or terminal fault at the engine control unit connectorrare
  • Internal driver fault in the engine control unitrare

How to diagnose

  1. Read all stored codes and freeze frame data, note whether the fault is current or intermittent, and check for related codes
  2. Locate the changeover valve 2 for the specific model and engine and inspect the connector and wiring for damage, corrosion, heat damage or chafing
  3. Disconnect and reconnect the connector, checking terminals for looseness, bent pins or green corrosion
  4. Use the manufacturer's diagnostic function to activate the valve and listen or feel for it clicking
  5. Measure the solenoid coil resistance and compare it with the specification for the engine
  6. Check the supply voltage and ground at the connector with the ignition on, and check the relevant fuse
  7. Test the wiring for continuity and shorts between the valve connector and the control unit, using the wiring diagram for the model
  8. Inspect the vacuum lines and actuator for splits or leaks once the electrical side is cleared

How to fix

  • Replace the intake manifold changeover valve if the coil is open circuit or fails the activation test
  • Clean, repair or replace the damaged connector or terminals
  • Repair or replace the damaged wiring section, using proper solder or crimp repairs and sealing
  • Restore the missing power supply by replacing a blown fuse once the cause of failure is found
  • Repair the control unit connector pins, or replace or repair the control unit only if all else is confirmed good, following the manufacturer's procedure

Can I keep driving?

Low severity

The car can normally be driven as the fault mainly affects performance and economy, but book it in soon. Avoid ignoring it for long as a stuck changeover system can reduce power and mask other developing faults.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.

This code for other makes

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