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P2004 Severity
Once the vehicle's onboard system no longer detects the issue, most codes will disappear on their own. If your vehicle still has this code, however, it should be properly diagnosed to avoid a more serious problem.
For a proper diagnosis, RepairPal Certified shops have the equipment, tools, and expertise.
Moderate severity codes might not threaten the vehicle's safety or functionality immediately, but you should still get it diagnosed within a reasonable time frame to keep your car running well.
The Intake Manifold Runner allows more air to flow through the intake at higher RPMs. If the Intake Manifold Runner does not operate as requested, P2004 will be set.
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Code P2004 stands for Intake Manifold Runner Control Stuck Open Bank 1
The intake manifold directs air into the engine via a series of runners. To improve engine performance, many late-model vehicles use what’s referred to as an intake manifold runner control (IMRC) system. An IMRC system varies manifold runner length via electrically controlled butterfly valves. Typically, the valves are operated by a solenoid that receives commands from the powertrain control module (PCM). The PCM determines IMRC control based on inputs from the throttle position sensor (TP) and crankshaft position sensor (CKP).
Code P2004 indicates the PCM has detected the bank 1 IMRC actuator is stuck in the open position. Bank 1 refers to the side of the engine with the #1 cylinder, whereas bank 2 refers to the side of the engine with the #2 cylinder. Inline engines, have only one bank – bank 1.
Intake manifold
Get it diagnosed by a professional
Code P2004 is typically caused by one of the following:
Sometimes P2004 can pop up in error. Clear the code and see if it returns. If it does, the next step is to perform a visual inspection. A trained eye can check for issues such as broken wires and loose connections. If a problem is found, it should be repaired and the code cleared. If nothing is discovered, check for technical service bulletins (TSBs). TSBs are recommended diagnostic and repair procedures put out by the vehicle manufacturer. Finding a related TSB can greatly reduce diagnostic time.
A technician will begin diagnosis of this code by checking IMRC actuator operation. The best way to do this is with a diagnostic scan tool. On most vehicles, the actuator can be commanded on and off with a scan tool, while monitoring its position on the screen. If the actuator position doesn’t change when commanded, there is either a problem with the actuator, its linkage or its circuit.
Next, the reason for the non-functional IMRC actuator must be determined. Checking the actuator circuit is the first step. In most cases, there are four wires going to the actuator: power, ground, signal and return. A digital multimeter (DMM) is used to check that all four portions of the circuit are working properly.
If a problem is found in the circuit, the factory wiring diagram will need to be traced. Then, once the problem area has been located, the open/short circuit can be repaired.
If the actuator and its circuitry check out, the manifold and its linkage will need to be inspected. The manifold many need to be removed for this. Once the manifold is off, the butterfly valves can be viewed from the underside. Depending on the design, the butterfly valves may be operated with mechanical linkage or with engine vacuum.
Note: It’s also a good idea to check the vacuum hoses on system that’s controlled by engine vacuum.