A p2004 code means the engine computer has detected that the bank 1 intake manifold runner control is stuck open. KBB describes it as a generic powertrain code that applies to 1996 and newer vehicles.
The wording changes by brand, and one code can point to an actuator, a sensor, wiring or a vacuum line. Start with a scan and a technician test before replacing any part.
What the p2004 code means on your engine
P2004 means the bank 1 intake manifold runner control (IMRC) is stuck in the open position. The engine control module sets a p2004 code, and bank 1 is the side of the engine that holds cylinder #1. KBB’s P2004 reference describes the fault the same way and lists the code as generic for 1996 and newer vehicles.
The IMRC works through butterfly valve plates inside the intake manifold, and the actuator solenoid moves them. Those plates can collect carbon, which is one reason a technician inspects them during diagnosis. According to KBB, the IMRC changes the length of the intake runners with those electrically controlled valves, and the engine computer controls them using inputs from the throttle position and crankshaft position sensors. KBB also notes that bank 2 is the side with cylinder #2, so an inline engine has only bank 1.
Because the code is generic, you will see a p2004 code on many makes and model years. The number stays the same, but the scan tool title and the repair steps can differ from one brand to another.
Why the wording differs between manufacturers
VW and Audi call this fault “Intake Manifold Flap; Bank 1: Stuck Open”, so the same condition can appear under another name on a brand scan tool. The table below compares the generic KBB entry with the VW and Audi entry in the Ross-Tech’s VW and Audi code wiki.
| Source | Fault title | Causes listed | Repair steps listed |
|---|---|---|---|
| KBB (generic) | Bank 1 intake manifold runner control stuck open | Actuator solenoid, solenoid wiring, MAP or IMRP sensor, vacuum solenoid debris, vacuum lines | Scan data, resistance tests, connector and part inspection |
| Ross-Tech (VW and Audi) | Intake Manifold Flap; Bank 1: Stuck Open | Vacuum leak, runner position sensor G336, runner binding or sticking | Replace failed vacuum line, check G336 wiring, output test, Basic Setting |
The Ross-Tech entry is organized by engine, not by model: it covers 2.0L TFSI engines (engine codes AXX, BGB, BPJ, BPY and BWA). Use the make, model and engine size of your own vehicle to find the matching entry rather than relying on the p2004 code number alone.
Ross-Tech also cites service bulletins that touch a p2004 code on these engines, which are worth confirming against your VIN with a dealer. For North America it lists TSB 24-17-04, which covers 2006-2008 BPY and 2008-2016 CCTA and CBFA engines and describes an improved intake manifold design. It also lists TSB 01-08-12, which calls for checking the engine control module software version and replacing the intake manifold runner (V157) with the updated part.
For 2012-2016 Audi 3.0 TFSI engines, Ross-Tech points to TPI 2050329: a vacuum-operated water pump may draw excessive vacuum and make the intake manifold flaps malfunction, and the fix is an updated vacuum hose for the water pump. A p2004 code on one of these engines can therefore start outside the intake manifold itself.
Common causes behind P2004
A faulty IMRC actuator solenoid, damaged solenoid wiring, a faulty MAP or runner position sensor, debris in the vacuum solenoid and disconnected vacuum lines are the causes KBB lists for a p2004 code.
- A faulty IMRC actuator solenoid
- Shorted, frayed or damaged solenoid wiring, circuitry or connectors
- A faulty MAP sensor or Intake Manifold Runner Position sensor
- Debris in the vacuum control solenoid or its filter
- Disconnected or damaged vacuum lines
The VW and Audi wiki adds a vacuum leak and runners that bind or stick as possible causes. A p2004 code alone does not show which of these failed, so the causes need to be tested one at a time. Vacuum leaks are also linked to lean codes such as the P0171 code, so scan for related codes before you decide.
This list covers the generic causes only. Your vehicle service information may list others, and a single fault can look like several of them.
Symptoms you may notice with P2004
KBB lists reduced engine performance at low RPM, a lit check engine light, lower fuel economy and surging or sputtering as the symptoms of this code.
- Reduced performance, especially at low RPM
- Check engine light on
- Lower fuel economy
- Engine surging or sputtering
Low-speed performance is the symptom to watch for with a p2004 code. KBB says the code should be taken very seriously, because parts of the IMRC can break loose and fall into the engine, which can cause costly engine damage. It advises against extended driving with the code, so book a diagnosis instead of waiting to see whether the problem goes away on its own. If a reduced-power message also appears on the dash, see the reduced engine power guide.
How a technician diagnoses P2004
Diagnosis starts with an OBD-II scan for freeze frame data and stored codes, followed by resistance and continuity tests on the IMRC circuit, according to KBB. The steps below follow that order.
- Pull freeze frame data and all stored trouble codes with an OBD-II scanner.
- Address any MAF sensor codes (for example the P0101 code), EGR valve codes such as the P0403 EGR circuit code, or BARO sensor codes first, as KBB advises.
- Test resistance and continuity in the IMRC circuit with a digital volt/ohmmeter.
- Inspect connectors and wiring for disconnection, corrosion or fraying.
- Inspect the IMRC solenoid, the EGR valve and the butterfly valve plates for damage, corrosion or carbon buildup.
On a VW or Audi, the wiki suggests an output test of the intake manifold flap. After a repair, it advises running Basic Setting with the ignition switched off.
KBB adds that carbon buildup on the butterfly plates can seep into the solenoid and damage it, which is why the plates are inspected along with the solenoid. These p2004 code steps need a scan tool that reads freeze frame data and a multimeter. Without them, replacing a part is a guess, and a p2004 code can return after the new part is installed.
What a p2004 repair involves and what it costs
KBB gives no repair cost for a p2004 code, so no price appears in this article. The cost depends on whether the fault is the actuator, a sensor, wiring or a vacuum line.
Because the causes range from a damaged vacuum line to the control solenoid, the job can be small or involve parts inside the intake. Ask the shop which test confirmed the failed part before you approve the work. If the EGR valve turns out to be the fault, the EGR valve repair cost guide shows how that job is priced.
Ask for a written estimate that names the tested part and the test result. Prices also vary by make, model and region, so compare quotes for your own vehicle.
When to see a technician about P2004
KBB recommends a qualified technician handle P2004 diagnosis and inspection rather than a do-it-yourself repair, because of the risk of severe damage to the vehicle or to the person doing the work. Book a visit if the check engine light stays on, the engine surges, or you lose power at low speed.
Frequently Asked Questions
Is a p2004 code serious?
KBB says the code should be taken very seriously and recommends a qualified technician handle the diagnosis. Do not ignore a p2004 code, because it affects engine performance and can cause surging or sputtering.
Can a vacuum leak cause P2004?
Yes, according to the Ross-Tech VW and Audi wiki, which lists a vacuum leak as a cause. KBB also lists disconnected or damaged vacuum lines. Check the lines and their connections first.
Does P2004 mean the IMRC actuator has failed?
Not necessarily. KBB lists wiring, sensors and vacuum parts as causes too, so the actuator is one possibility among several. Testing is needed to confirm which part failed.
Which codes should be checked before P2004?
KBB advises addressing codes for the MAF sensor, EGR valve or BARO sensor first. Those codes come before the IMRC circuit in the diagnosis.
Does P2004 apply to every car?
KBB calls it a generic code for 1996 and newer vehicles, but brands word it differently. Check the fault title and steps for your make, model and engine.
