Intake Manifold Runner Control Circuit Low Bank 2
The Powertrain Control Module (PCM) detected that the voltage signal from the Intake Manifold Runner Control (IMRC) actuator circuit for Bank 2 is lower than the expected threshold. This indicates a potential short to ground or a failure in the actuator motor or solenoid controlling the intake manifold butterfly valves on the engine bank opposite of cylinder 1.
While the vehicle is usually safe to drive, the engine may experience reduced performance, poor fuel economy, or rough idling. It should be diagnosed soon to restore proper engine operation and prevent potential long-term emissions issues.
Common symptoms
- Illuminated Check Engine Light (MIL)
- Rough or fluctuating engine idle
- Reduced engine power or hesitation during acceleration
- Decreased fuel efficiency
- Engine stalling at low speeds
Likely causes
- Faulty Intake Manifold Runner Control (IMRC) actuator or solenoid for Bank 2
- Damaged, corroded, or loose wiring and connectors in the IMRC circuit
- Short to ground in the IMRC control circuit
- Carbon buildup or physical binding of the intake manifold runner flaps
- Vacuum leak in the IMRC system (if vacuum-operated)
- Faulty Powertrain Control Module (PCM) (rare)
What to check before replacing parts
Scan for additional codes and record freeze frame data.
Look for: Check if other IMRC or circuit codes are present which might indicate a shared ground or power supply issue.
Visually inspect the IMRC actuator, wiring harness, and connectors for Bank 2.
Look for: Look for chafed wires, melted insulation, or corroded pins that could cause a short to ground.
Test the IMRC actuator circuit for voltage and ground using a digital multimeter.
Look for: A reading of zero or significantly lower than battery voltage on the control wire when commanded on indicates a short to ground or open circuit.
Manually actuate the intake manifold runner linkage for Bank 2.
Look for: Resistance, binding, or sticking in the linkage indicates carbon buildup or mechanical failure of the flaps, rather than just an electrical issue.
Perform a bi-directional control test using an advanced scan tool to command the IMRC actuator.
Look for: If the scan tool commands the actuator but it does not move and circuit voltage drops abnormally, the actuator itself is likely internally shorted and needs replacement.
This page explains the generic P2012 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.
Gear guide: Best OBD2 ScannersRead this code yourself next time — from $20 Bluetooth dongles to bidirectional scan tools.Rather have a pro handle it? Find a vetted local mechanic.