Technical Description of OBD-II Trouble Code
This trouble code, Intake Manifold Runner Position Sensor / Switch Circuit Intermittent Bank 2, is a generic powertrain/engine diagnostic code that is applicable to fuel injected engines from most manufacturers since 2003.
These manufacturers include Ford, Dodge, Toyota, Mercedes, Volkswagen, Nissan, and Infiniti.
This code primarily focuses on the value provided by the intake manifold flow control valve/position sensor, also known as the IMRC valve/sensor. This component, typically located at one end of the intake manifold, assists the vehicle’s PCM in controlling the amount of air allowed into the engine at different RPMs. The code specifically pertains to Bank 2, which refers to the bank of cylinders that does not include cylinder number 1. The issue can be either a mechanical or electrical circuit fault, depending on the vehicle manufacturer and fuel system.
The troubleshooting steps may vary depending on the manufacturer, type of fuel system, and the type of intake manifold runner control valve/position (IMRC) sensor and wire colors.
Meaning of the Code
A P2023 engine code may exhibit the following symptoms:
Possible Causes
The typical causes for this code to be set are:
(programming required after replacement)
Diagnostic Steps and Repair Information
A good starting point is to check for technical service bulletins (TSB) specific to your vehicle. There may be a known issue with a known fix provided by the manufacturer, which can save time and money during diagnosis.
The most common failure items (and often misdiagnosed items) in these systems are the IMRC vacuum solenoids, which can accumulate carbon and hinder proper venting, and the IMRC plates sticking or binding due to carbon deposits.
First, check for any other diagnostic fault codes. If there are any intake/engine performance system related codes, diagnose them first. Misdiagnosis can occur if this code is diagnosed before thoroughly diagnosing and dismissing any intake/engine performance related system codes. Ensure there are no intake or exhaust leaks, as an intake or vacuum leak can cause the engine to run lean, and an exhaust leak can give the impression of a lean running engine based on the air fuel ratio/oxygen (AFR/O2) sensor.
The next step is to locate the bank 2 IMRC valve/sensor in your specific vehicle. Once located, visually inspect the connectors and wiring for any signs of damage such as rubbing, scraping, bare wires, worn spots, or melted plastic connectors. Separate the connectors and carefully examine the terminals inside for any signs of burning or corrosion. If necessary, clean the terminals using Electrical Contact cleaner or rubbing alcohol and a small plastic bristle brush. After cleaning, allow them to air dry. Apply dielectric silicone compound to the connector cavity before reassembling.
If you have a scan tool, clear the diagnostic trouble codes from memory and check if this code returns. If it does not, the issue was likely related to the connections.
If the code does return, you will need to test the voltage signals to and from the IMRC valve/sensor using a scan tool or a digital volt ohm meter (DVOM). With the sensor connected, monitor the IMRC sensor voltage on the scan tool or test the signal with the DVOM. The IMRC sensor signal should change as the engine RPM increases. Refer to the manufacturer’s specifications for the expected voltage at a given RPM.
If the IMRC sensor fails this test, you will need to verify that the IMRC valve moves smoothly without binding or sticking inside the intake manifold. Remove the IMRC sensor/actuator and check for any binding or looseness in the plates/valves inside the intake manifold. If necessary, replace the plates/valves, which may require replacing the entire intake manifold. It is recommended to seek professional assistance for this task.
It is crucial to diagnose all other codes before addressing this one, as issues that cause other codes to set can also trigger this code. Additionally, if the problem is not apparent after the initial diagnosis steps, consulting with an automotive professional is advisable. Many repairs beyond this point involve removing and replacing the intake manifold to properly resolve this code and the related engine performance issue.
