Intake Manifold Runner Position Sensor/Switch Circuit Intermittent Bank 1
P2018 indicates the intake manifold runner control (IMRC) system on Bank 1 is not functioning properly or is stuck in an incorrect position. The IMRC system optimizes engine performance by adjusting intake runner length based on engine speed, and when it fails, the engine cannot properly tune its air intake for different operating conditions.
What You Might Notice
- Check Engine Light illuminated
- Loss of engine power or reduced acceleration
- Occasional misfires during acceleration
- Poor fuel economy
- Rough idle or hesitation
Most Common Causes
- 1
Sticking or faulty IMRC valve
The intake manifold runner control valve becomes stuck or fails to move smoothly, preventing proper adjustment of intake runner position. Carbon buildup or mechanical wear commonly causes this.
- 2
Faulty IMRC actuator
The actuator motor or solenoid that controls valve movement malfunctions electrically or mechanically, preventing the valve from responding to PCM commands.
- 3
Sticking throttle body or plates
Contaminated or stuck throttle plates can interfere with proper air metering and trigger related IMRC system faults.
- 4
Faulty IMRC position sensor
The sensor that monitors valve position may provide incorrect feedback to the PCM, causing it to detect an intermittent circuit condition.
How to Diagnose It
- 1
Check Sticking or faulty IMRC valve — The intake manifold runner control valve becomes stuck or fails to move smoothly, preventing proper adjustment of intake runner position. Carbon buildup or mechanical wear commonly causes this.
- 2
Check Faulty IMRC actuator — The actuator motor or solenoid that controls valve movement malfunctions electrically or mechanically, preventing the valve from responding to PCM commands.
- 3
Check Sticking throttle body or plates — Contaminated or stuck throttle plates can interfere with proper air metering and trigger related IMRC system faults.
- 4
Check Faulty IMRC position sensor — The sensor that monitors valve position may provide incorrect feedback to the PCM, causing it to detect an intermittent circuit condition.
How to Fix It
- 1
Clean or replace IMRC valve
Remove the intake manifold and inspect the IMRC valve for carbon buildup or damage. Clean with appropriate solvent or replace if worn. Reinstall and clear the code.
- 2
Replace IMRC actuator
Test the IMRC actuator for electrical continuity and mechanical movement. If faulty, disconnect electrical connectors and unbolt the actuator, then install a new unit and reconnect.
- 3
Clean throttle body and plates
Remove the throttle body assembly and clean all throttle plates and passageways with carburetor cleaner to remove carbon deposits. Reinstall and retest.
- 4
Replace IMRC position sensor
Locate the IMRC position sensor, disconnect its electrical connector, remove the fastener, and install a new sensor. Reconnect and clear the diagnostic code.
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