P2009Generic code

P2009 Code: Intake Manifold Runner Control Circuit Low (Bank 1)

The P2009 code means low voltage in the control circuit of the bank 1 intake manifold runner control valves, from a short to ground or a loss of power. It can cause a loss of torque at low rpm and a slightly rough idle. The engine runs, with a little less performance.

Severity
Low
Can I keep driving?
Yes, no immediate risk
Estimated cost
$40 to $450
Difficulty
Medium
System
Air and Fuel
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P2009 code means

Many engines have flaps or valves in the intake manifold (IMRC, Intake Manifold Runner Control, also called swirl or tumble flaps) that change the length or shape of the intake runner. At low rpm they close so the air enters faster and with more turbulence, which improves torque and combustion. At high rpm they open to let more air through. An electric motor or a vacuum actuator controlled by a solenoid moves them, and a position sensor tells the computer whether they really moved.

The computer watches the control circuit from its own driver transistor. The P2009 code means low voltage in the control circuit, from a short to ground or a loss of power. Before you replace the component, check the fuse, the relay, the connector and the wiring, because they are the most common cause.

The computer does the commanding on an electric actuator or on the solenoid that supplies vacuum to the pneumatic actuator. Bank 1 is the side of the engine where cylinder number 1 is. Inline engines only have bank 1. On V engines, bank 2 is the opposite side.

To confirm the diagnosis, unplug the component with the key on and see what happens to the reading or the code. If the value jumps to the opposite extreme, the wiring is fine and the component is the part pulling the signal to ground. If nothing changes, go hunting for the short in the wire, starting where the harness rubs against the engine, the chassis or the exhaust.

P2009 code symptoms

  • Check engine light or another warning light on.
  • Loss of torque at low rpm and a slightly uneven idle.

Likely causes of the P2009 code

  1. Control wire shorted to ground. The component can stay on all the time, or the computer cuts the command to protect itself.
  2. Interrupted power supply. A blown fuse, a bad relay or a cut wire.
  3. Component shorted. The resistance is much lower than specified.
  4. Connector with moisture. It creates a path to ground.

How to diagnose the P2009 code step by step

  1. Activate the component with the scan tool and check whether it responds.
  2. Check the fuse and the relay. Measure voltage on both sides of the fuse, and swap the relay with an identical one.
  3. Measure the supply at the connector. You should see battery voltage with the key on or when it is activated.
  4. Measure the resistance of the component and compare it with the manual. Check the insulation to ground too.
  5. Check the control wire. Look for continuity all the way to the computer and for any short circuit.

How to fix the P2009 code

  • Repair the connector, the wiring or the power supply.
  • Replace the intake manifold runner control valves if they do not respond with correct power and control.
  • Clear the codes and verify.

Technical reference data

  • Vacuum actuator: it should hold about 15 to 20 inHg without losing vacuum for one minute.
  • Electric actuator: 12 volt supply, with control by a PWM signal or by reversing polarity.
  • Position sensor: 5 volt reference and a signal of roughly 0.5 to 4.5 volts depending on the flap position.
  • These values are only a guide, so look up the manufacturer data for your vehicle.

Brand-specific notes

On some diesels the flaps fill up with carbon and can break. A fragment inside the cylinder can cause a serious failure, so some shops remove the flaps following manufacturer procedures.

P2009 on Ford and Mazda

This code is frequent on Ford Duratec and Mazda MZR gasoline engines.

P2009 on Volkswagen, BMW, Mercedes-Benz and Fiat

It is also frequent on the diesel engines with swirl flaps from Volkswagen, BMW, Mercedes-Benz and Fiat.

P2009 on GM V6 Engines

Several GM V6 engines are also known for this code.

Frequently asked questions about P2009

Can I drive with a P2009 code?
Yes. The engine runs, with a little less performance.
What do the intake manifold runner control valves do?
They are flaps in the intake manifold (IMRC, also called swirl or tumble flaps) that change the length or shape of the runner. At low rpm they close so the air enters faster and with more turbulence, which improves torque and combustion. At high rpm they open to let more air through.
Does the part always have to be replaced?
No. Check the fuses, relays, connectors and wiring first.
How much does it cost to fix P2009?
Roughly $40 to $450.
What does the P2009 code mean?
It is a generic OBD2 code that means the control circuit of the bank 1 intake manifold runner control valves has low voltage, from a short to ground or a loss of power.
Will a P2009 code clear itself?
Only if the cause was a passing glitch. A wire shorted to ground or a wet connector will bring the P2009 code back.
What is the most common cause of P2009?
A control wire shorted to ground, or a power supply that is interrupted by a blown fuse, a bad relay or a cut wire. Check those before you replace the valves.

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