Intake Manifold Runner Control Circuit Low Bank 1
The powertrain control module (PCM) has detected that the voltage signal from the Intake Manifold Runner Control (IMRC) circuit for Bank 1 is below the expected threshold. This typically indicates a short to ground in the wiring or a failure within the IMRC actuator itself.
While the vehicle is usually safe to drive, this issue can cause poor engine performance, reduced fuel economy, and increased emissions. It should be diagnosed and repaired soon to restore proper engine operation.
Common symptoms
- Illuminated Check Engine Light
- Rough or unstable engine idle
- Hesitation or stumbling during acceleration
- Reduced overall engine power
- Decreased fuel efficiency
Likely causes
- Faulty Intake Manifold Runner Control (IMRC) actuator/solenoid
- Wiring harness shorted to ground in the IMRC circuit
- Corroded or loose electrical connection at the IMRC actuator
- Binding or stuck intake manifold runner flaps
- Failed Powertrain Control Module (PCM)
What to check before replacing parts
Visually inspect the IMRC actuator wiring harness and connector.
Look for: Look for chafed wires, melted insulation, or a short to ground, as well as bent pins or corrosion inside the connector.
Test the IMRC actuator solenoid resistance using a multimeter.
Look for: Compare the measured resistance to the manufacturer's specifications; an out-of-spec reading or continuity to ground indicates a failed actuator.
Check for proper reference voltage and ground at the IMRC connector.
Look for: With the key on, verify the presence of the required voltage (usually 12V or 5V depending on the system) and a solid ground; lack of voltage suggests a wiring or relay issue.
Manually operate the intake manifold runner linkage.
Look for: Disconnect the actuator and move the linkage by hand to ensure the flaps move freely without binding or excessive resistance.
Command the IMRC actuator using a bi-directional scan tool.
Look for: Observe if the actuator moves the linkage when commanded; if it receives the command but does not move, the actuator is likely defective.
This page explains the generic P2009 definition and is general reference information, not a diagnosis for your specific vehicle. Actual causes, severity, and repairs vary by make, model, engine, and mileage — always confirm with a scan tool and a qualified technician before replacing parts.
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