Intake Manifold Runner Position Sensor/Switch Circuit High Bank 1
The intake manifold runner control (IMRC) system is not responding as expected, indicating a fault in the actuator, sensor, or relay that controls variable intake runner length. This system optimizes engine performance across different RPM ranges, and its failure reduces power and efficiency.
What You Might Notice
- Check engine light illuminated
- Reduced engine power or acceleration
- Poor fuel economy
- Rough idle or hesitation
- Lack of high-RPM performance
Most Common Causes
- 1
Faulty IMRC actuator
The actuator that physically moves the intake runner flaps has failed or is stuck. This is the most common cause and prevents proper adjustment of the intake manifold runners.
- 2
IMRC actuator relay failure
The relay controlling power to the IMRC actuator has failed, cutting electrical supply to the system. Testing the relay with a multimeter can confirm this fault.
- 3
IMRC position sensor malfunction
The sensor monitoring the runner flap position is sending incorrect signals to the PCM. This prevents the control module from verifying proper IMRC operation.
- 4
Wiring or connector issues
Corroded connectors, broken wires, or loose connections in the IMRC circuit are preventing proper electrical communication. Visual inspection under the intake manifold area should reveal obvious damage.
How to Diagnose It
- 1
Check Faulty IMRC actuator — The actuator that physically moves the intake runner flaps has failed or is stuck. This is the most common cause and prevents proper adjustment of the intake manifold runners.
- 2
Check IMRC actuator relay failure — The relay controlling power to the IMRC actuator has failed, cutting electrical supply to the system. Testing the relay with a multimeter can confirm this fault.
- 3
Check IMRC position sensor malfunction — The sensor monitoring the runner flap position is sending incorrect signals to the PCM. This prevents the control module from verifying proper IMRC operation.
- 4
Check Wiring or connector issues — Corroded connectors, broken wires, or loose connections in the IMRC circuit are preventing proper electrical communication. Visual inspection under the intake manifold area should reveal obvious damage.
How to Fix It
- 1
Replace IMRC actuator
Remove the intake manifold runner control actuator and install a new one. This typically involves disconnecting the electrical connector and removing mounting bolts underneath or on the side of the intake manifold.
- 2
Replace IMRC relay
Locate the IMRC relay in the engine bay relay box (consult your service manual for exact location), pull it out, and install a new relay with identical part number. This is a quick electrical fix.
- 3
Inspect and repair wiring
Check all connectors and wiring harnesses associated with the IMRC system for corrosion, loose connections, or broken wires. Clean corroded connectors with electrical contact cleaner and reseat connections firmly.
- 4
Replace IMRC position sensor
If the sensor is faulty, disconnect the electrical connector and remove the sensor from its mounting location. Install the new sensor and reconnect, ensuring proper seating to avoid air leaks.
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