Intake Manifold Runner Control Stuck Open Bank 1
The P2004 code indicates that the Powertrain Control Module (PCM) has detected that the intake manifold runner control (IMRC) valve on bank 1 is stuck in the open position. The IMRC system uses flaps or valves inside the intake manifold to optimize airflow at different engine speeds. When stuck open, the engine loses low-end torque and may experience reduced fuel efficiency. This can be caused by carbon buildup, a faulty actuator, or a broken linkage.
01. Most Common Causes
- Carbon buildup on the IMRC flaps or shaft
- Faulty IMRC actuator or solenoid
- Broken or disconnected vacuum lines (if vacuum-operated)
- Wiring or connector issues to the IMRC actuator
- Failed PCM (rare)
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Reduced engine power, especially at low RPM
- Poor fuel economy
- Rough idle or hesitation during acceleration
03. Step-by-Step Diagnosis
Step 1: Use an OBD2 scanner to confirm P2004 and check for other codes.
Step 2: Visually inspect the IMRC actuator and linkage for damage or carbon buildup.
Step 3: Test the IMRC actuator operation using a scan tool or manual vacuum pump (if applicable).
Step 4: Check wiring and connectors for corrosion or breaks.
Step 5: If necessary, remove the intake manifold to clean or replace the IMRC flaps.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
You can drive short distances, but expect reduced performance and fuel economy. Prolonged driving may cause further carbon buildup or damage to the intake manifold.
How much does it cost to fix?▼
Repair costs range from $150 to $400, depending on the cause. Cleaning the intake manifold may cost less, while replacing the actuator or manifold can be more expensive.