Intake Manifold Runner Position Sensor/Switch Circuit Low Bank 2
P2021 indicates the Intake Manifold Runner Control (IMRC) system on Bank 2 is not operating properly, likely due to a faulty actuator, sensor, or relay. The IMRC adjusts intake runner lengths to optimize engine performance across different RPM ranges, and when it malfunctions, the engine cannot properly control airflow.
What You Might Notice
- Check Engine Light illuminated
- Lack of engine power or acceleration
- Poor fuel economy
- Rough idle or hesitation under load
- Reduced torque response
Most Common Causes
- 1
Faulty IMRC Actuator Bank 2
The actuator motor on Bank 2 has failed or become stuck, preventing proper runner position adjustment. This is the most common cause of P2021.
- 2
Faulty IMRC Sensor Bank 2
The position sensor monitoring the runner position is sending incorrect signals or has failed, causing the PCM to set the code even if the actuator functions correctly.
- 3
Faulty IMRC Actuator Relay
The relay controlling power to the Bank 2 actuator has failed, preventing the actuator from receiving voltage and operating as intended.
- 4
Faulty Powertrain Control Module
Rarely, the PCM itself may malfunction or have corrupted programming related to IMRC control, though this is an uncommon cause.
How to Diagnose It
- 1
Check Faulty IMRC Actuator Bank 2 — The actuator motor on Bank 2 has failed or become stuck, preventing proper runner position adjustment. This is the most common cause of P2021.
- 2
Check Faulty IMRC Sensor Bank 2 — The position sensor monitoring the runner position is sending incorrect signals or has failed, causing the PCM to set the code even if the actuator functions correctly.
- 3
Check Faulty IMRC Actuator Relay — The relay controlling power to the Bank 2 actuator has failed, preventing the actuator from receiving voltage and operating as intended.
- 4
Check Faulty Powertrain Control Module — Rarely, the PCM itself may malfunction or have corrupted programming related to IMRC control, though this is an uncommon cause.
How to Fix It
- 1
Replace IMRC Actuator Bank 2
Remove and replace the intake manifold runner control actuator on the Bank 2 side of the engine. Access typically requires removing the intake manifold cover and disconnecting electrical and mechanical linkages.
- 2
Replace IMRC Position Sensor Bank 2
Locate and replace the position sensor for the Bank 2 runner control system. The sensor is typically mounted on or near the actuator assembly and can usually be accessed without full manifold removal.
- 3
Replace IMRC Actuator Relay
Locate the relay controlling the Bank 2 IMRC actuator (typically in the engine bay fuse/relay box) and replace it with a new unit of the same specifications.
- 4
Reprogram or Replace PCM
If other components test normal, the PCM may require reprogramming or replacement. This requires specialized equipment and should only be performed by qualified technicians with access to manufacturer software.
Need a deeper diagnosis?
Search for related repair guides or browse by system.