What it means
The control module has detected the intake manifold runner control stuck open on bank 1. The code does not establish the runner design or a particular effect on engine operation.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The intake manifold runner control changes airflow through the intake manifold on bank 1 to support engine operation under different conditions. The control module sets P2004 when the bank 1 runner control is detected stuck open, so the runners are not moving to the commanded position and the engine may lose low-speed response or run roughly.
Common causes
Most likely first.
- Carbon buildup blocks flap travel
- IMRC actuator or vacuum motor failed
- Linkage rod broken or disconnected
Symptoms
- Check-engine light
- Reduced engine power or sluggish acceleration
- Rough idle or hesitation
How to diagnose it
- Record freeze-frame data and check for related intake or actuator codes, then compare commanded and reported bank 1 runner position if scan data is available.
- With the engine off, inspect the bank 1 runner linkage and flap mechanism for carbon buildup, a disconnected or broken rod, or visible binding.
- Check the bank 1 actuator connector and wiring for loose pins, corrosion, or damage.
- If the system uses a vacuum motor, inspect its hoses and test whether it holds vacuum; for an electric actuator, check its circuit and command response using the manufacturer's procedure.
- If the linkage and actuator operate but the code returns, check the bank 1 runner position feedback and intake mechanism for sticking.
Common fixes
- Clean carbon deposits that are preventing bank 1 runner flaps from moving.
- Reconnect or replace a broken bank 1 runner linkage rod.
- Repair damaged actuator wiring, connectors, or vacuum hoses.
- Replace the bank 1 runner actuator if testing confirms it has failed.
Can I keep driving?
The engine may hesitate, idle roughly, or have reduced power, especially during acceleration. Avoid hard acceleration if response is poor, and address the fault before reduced airflow control leads to worsening drivability or emissions.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.