OBD-II Diagnostic Trouble Code
P2004 — Intake Manifold Runner Control Stuck Open Bank 1
P2004 means the intake manifold runner control on bank 1 is stuck open. The ECM commanded the runners closed but position feedback shows they stayed open. On diesels this may be called swirl or tumble flap control.
Severity 3/5
Truck-relevant
Service this week
Severity
Service this week
Intake Manifold Runner Control Stuck Open Bank 1
Code
P2004
Category
Powertrain
Subsystem
Air Flow
Truck-relevant
Yes
What this means for truckers
P2004 (Intake Manifold Runner Control Stuck Open, Bank 1) — IMRC (intake runner control) flap is stuck open. On commercial diesels with variable intake systems (rare — mostly Detroit DD15 and some Cummins), this affects low-end torque. Carbon buildup is the usual cause; cleaning fixes most.
Before you replace parts — try this first
P2004 on the Air Flow system is most often carbon or soot buildup jamming the runner flaps — not a dead part. On commercial diesels especially, work these in order before spending money on parts:
- Confirm the symptoms. Match what your truck is doing to the Symptoms section below. If the code is set but the symptoms are not there, clear the code and re-test after a drive cycle — it may not return.
- Clean and dry the sensor connector. Water, road salt, or oil seeping into a connector is the #1 fake sensor failure. Disconnect, look for green corrosion or moisture, spray with electrical contact cleaner, dry, reseat. Many faults clear here for $0.
- Inspect the wiring harness. Trace the wire from the sensor toward the ECM — look for chafing against the engine block, melted insulation near the turbo or exhaust, or pinch points where a clamp has rubbed through.
- Test the sensor before swapping it. Most Common Causes (below) list the expected voltage or resistance range — a $20 multimeter saves a $300 sensor swap that does not fix the problem.
- Only then, replace the part. Use the OEM or a tier-1 aftermarket. Cheap sensors throw the same code in two weeks.
Symptoms
Weak low-rpm torque, rough idle, possible higher emissions and a check-engine light.
Common causes
- CommonCarbon or soot buildup jamming the runner flaps ($200–$800)
- CommonFailed runner actuator ($200–$700)
- OccasionalBroken linkage ($80–$300)
- OccasionalFaulty position sensor or wiring ($100–$350)
How to fix
Command the runner with a scan tool and watch it move
When to use: First step
Inspect the linkage and actuator
When to use: When it does not move
Clean or replace the intake manifold
When to use: When flaps are jammed
Replace the actuator
When to use: When it fails
Affects most
No specific vehicle pattern found in our complaint database. This code can appear on any vehicle that supports OBD-II diagnostics.
Related
- → Browse all DTC trouble codes
- → Decode a VIN to check codes for your truck
- → Owner-operator maintenance guides
- → P2002 — Diesel Particulate Filter Efficiency Below Threshold (Bank 1)
- → P2003 — Diesel Particulate Filter Efficiency Below Threshold (Bank 2)
- → P2031 — Exhaust Gas Temperature Sensor Bank 1 Sensor 2
- → P2032 — Exhaust Gas Temperature Sensor Bank 1 Sensor 2 Low
- → P2033 — Exhaust Gas Temperature Sensor Bank 1 Sensor 2 High
Frequently Asked Questions
Can I drive with code P2004?
P2004 is severity 3 — plan service within a few days. Performance is likely degraded already (you may feel reduced power, harsher shifts, or slightly worse fuel economy). Continuing to drive risks additional damage to adjacent components.
How much does it cost to fix P2004 on a commercial truck?
Total repair cost ranges $80–$800 depending on the root cause. The cheapest fix is usually the first one listed below — Carbon or soot buildup jamming the runner flaps — which is also the most common. On commercial trucks the cost is usually higher than passenger vehicles due to part availability and shop labor rates ($120–185/hour at most truck shops, vs $90–130 at general auto shops). DIY-capable fixes (sensors, hoses, filters) are at the low end; major component replacements (turbo actuator, high-pressure fuel pump, transmission solenoid pack) are at the high end. Always diagnose with a scan tool BEFORE replacing parts — guessing wrong on a $1,500 turbo actuator when the actual issue was a $30 boost hose is a common expensive mistake.
Will P2004 fail a DOT inspection?
P2004 is generally not a direct DOT inspection fail item by itself. Inspectors focus on safety-critical systems (brakes, steering, tires, lights, hours-of-service). However, the check engine light alone can trigger additional inspection scrutiny. Best practice: fix the code and clear it before a planned inspection.
What's the difference between P2004 and related codes?
P2004 is closely related to: P2002 (Diesel Particulate Filter Efficiency Below Threshold (Bank 1)), P2003 (Diesel Particulate Filter Efficiency Below Threshold (Bank 2)), P2031 (Exhaust Gas Temperature Sensor Bank 1 Sensor 2), P2032 (Exhaust Gas Temperature Sensor Bank 1 Sensor 2 Low). These codes share the same subsystem (air-flow) and often appear together. If you see this code, scan for the full code list — fixing the root cause usually clears multiple companion codes at once. If only P2004 is set without the companions, the issue is more isolated.
How do I prevent P2004 from coming back after a repair?
For P2004 (Intake Manifold Runner Control Stuck Open Bank 1), prevention centers on the air flow system. Service air filter on time. Clean MAF sensor at every air filter change. Inspect intake boots/hoses for cracks — vibration kills them eventually.