Fuel and air

P1520 — Intake Manifold Runner Control Circuit Malfunction (Bank 2)

Severity: low Safe to drive

What P1520 means

P1520 is a manufacturer-specific code, and its definition varies by brand. On Ford, Land Rover and Mazda it points to a fault in the intake manifold runner control circuit. These runners or flaps change the airflow path with engine speed and load to improve torque and efficiency. The control unit sets the code when the bank 2 circuit signal or state does not match what it expects.

Symptoms

  • Loss of power, especially at mid to high rpm
  • Rough idle on V engines
  • Check Engine light on
  • Worse fuel economy
  • Sluggish throttle response

Possible causes

  1. Failed bank 2 runner actuator (solenoid or motor)
  2. Open, shorted or corroded wiring or connector
  3. Vacuum supply problem: cracked hose, bad vacuum valve or reservoir
  4. Sticking or carbon-clogged runners, or a broken linkage
  5. PCM fault (rare)

How to diagnose

  1. Read all codes and freeze frame data and look for related codes
  2. Confirm the code definition for your brand in service information
  3. Inspect vacuum hoses, valve and reservoir for cracks and leaks
  4. Inspect the bank 2 actuator connector and harness for corrosion, chafing or breaks
  5. Check power and ground at the actuator connector with a multimeter
  6. Command the actuator with a scan tool and watch whether the linkage moves
  7. Move the runners by hand to check for binding
  8. Measure actuator coil or motor resistance against specification

Common fixes

  • Replace the bank 2 runner actuator
  • Repair the wiring or connector
  • Replace the vacuum valve, hoses or reservoir
  • Clean or replace the runners and their linkage
  • Clear the code and confirm it does not return

P1520 on different brands

Ford · manuals
Intake manifold runner control circuit fault.
Land Rover
Intake manifold air control system circuit malfunction.
Mazda · manuals
Intake manifold air control circuit malfunction.
Chrysler
Listed as a Gear Indicator System fault, not an intake issue, so check that circuit.
Dodge · manuals
Listed as a cruise control master switch malfunction.
Lexus · manuals
Listed as a stop lamp switch signal malfunction.
Mercedes-Benz · manuals
Listed as a fault with cruise control switch S40.
MINI
Listed as camshaft position actuator 'B' bank 1.

Questions and answers

Can I drive with a P1520 code?

Usually yes, but power and idle quality may suffer. Get it diagnosed soon.

Why does P1520 mean different things on different brands?

It is a manufacturer-specific code, so each brand defines it on its own. Check the documentation for your exact vehicle.

What should I check first?

Start with vacuum hoses and the vacuum valve, then the bank 2 actuator connector and wiring. Test the actuator itself last.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.