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P2004 on Mercedes-Benz G-Class

Intake Manifold Runner Control (IMRC) Stuck Open (Bank 1)

Factory diagnostic protocol and troubleshooting wire for fault code P2004 specifically for the Mercedes-Benz G-Class (2020–2026, 4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550).

Verified OEM Telemetry & Field Repair Tree
Mercedes-Benz G-Class2020–2026
Mercedes-Benz G-Class
SUV4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550
Reliability
Sensor Voltage Ref
0.1V – 5.0V Ref
G-Class SAE Mode $01
ECU Network Bus
500 kbps CAN-FD
ISO 15765-4 Compliant
Drivability Status
Drivable (Short Trip)
Medium urgency level
Est. Repair Cost
$150 - $600 (DIY: $40 - $180)
Parts & Labor DIY
Check P2004 On Another Mercedes-Benz Model:
Diagnose P2004 on Specific G-Class Model Year:

1. Symptoms of P2004 on Mercedes-Benz G-Class

When the Engine Control Module (ECM/PCM) on your Mercedes-Benz G-Class (4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550) logs fault code P2004, drivers commonly observe:

Check Engine Light on on Mercedes-Benz G-Class (4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550)
Sluggish low-RPM acceleration and low-end torque loss on Mercedes-Benz G-Class (4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550)
Engine runs fine at high highway RPMs (3,500+ RPM) on Mercedes-Benz G-Class (4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550)
Slightly rough idle or minor intake whistling noise on Mercedes-Benz G-Class (4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550)
Mercedes-Benz G-Class OBD-II Port Location
The 16-pin diagnostic connector is located Driver side lower knee panel behind OBD door. Plug in your scan tool to verify freeze-frame sensor values.

2. Most Likely Causes on Mercedes-Benz G-Class

Historical warranty claims and technical repair bulletins for Mercedes-Benz G-Class point to the following failure distribution:

55%
Carbon buildup binding the intake manifold swirl flap runner plates (Mercedes-Benz OEM Part)
25%
Broken plastic IMRC actuator linkage rod or vacuum diaphragm (Mercedes-Benz OEM Part)
12%
Faulty electronic IMRC runner control motor / solenoid (Mercedes-Benz OEM Part)
8%
Cracked vacuum line to IMRC actuator (Mercedes-Benz OEM Part)
* Source: Synthesized from NHTSA ODI field repair telemetry and verified OEM Technical Service Bulletin (TSB) repair tree frequency percentiles for Mercedes-Benz G-Class.

3. Step-by-Step DIY Repair Guide for Mercedes-Benz G-Class

01
Visually Inspect IMRC Actuator Linkage

Check the mechanical plastic linkage arms at the end of the intake manifold. Verify arms are not popped off or broken. on the Mercedes-Benz G-Class equipped with 4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550.

Required Tool: Flashlight, Mirror
02
Test Runner Flap Movement Manually

Move the runner lever by hand. It should spring back smoothly without binding or gritty resistance. on the Mercedes-Benz G-Class equipped with 4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550.

Required Tool: None
03
Test IMRC Solenoid / Actuator Motor

Command IMRC open and closed with bi-directional scan tool or check vacuum supply to diaphragm. on the Mercedes-Benz G-Class equipped with 4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550.

Required Tool: OBD-II Bi-Directional Scanner or Vacuum Gauge
04
Clean Intake Manifold Carbon or Replace Actuator

Replace the broken linkage/actuator motor or remove manifold to clean heavy carbon deposits around the butterfly flaps. on the Mercedes-Benz G-Class equipped with 4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550.

Required Tool: Socket Set, Carburetor Cleaner, Gasket Set
05
Clear DTCs and Verify Runner Operation

Clear trouble codes and confirm low-end acceleration is restored. on the Mercedes-Benz G-Class equipped with 4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550.

Required Tool: OBD-II Scanner
Recommended Parts & Testing Tools

Equipment for Diagnosing Mercedes-Benz G-Class (P2004)

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Mercedes-Benz G-Class OEM Replacement Sensor

4.7 / 5.0 (Verified Fit)

Direct-fit replacement assembly engineered to OEM tolerances for Mercedes-Benz G-Class.

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Sensor Signal Voltage Meter

AstroAI Auto-Ranging Digital Multimeter

4.6 / 5.0 (Best Seller)

Essential for testing 0.1V–5.0V sensor reference signals, ground continuity (<0.20Ω), and harness resistance.

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Top Mobile OBD-II Scanner

BlueDriver Bluetooth Pro OBDII Scan Tool

4.7 / 5.0 (50,000+ Reviews)

Reads and clears enhanced codes (ABS, Airbag, Transmission, Engine) & live freeze-frame telemetry on phone.

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Other Common Fault Codes on Mercedes-Benz G-Class

Frequently diagnosed powertrain, emissions, and sensor trouble codes logged on the Mercedes-Benz G-Class:

4. Mercedes-Benz G-Class P2004 FAQs

What causes code P2004 to trigger on a Mercedes-Benz G-Class?

On the Mercedes-Benz G-Class (4.0L Bi-Turbo V8 (M177 AMG G 63 577HP) / 3.0L I6 Mild Hybrid G 550), P2004 is most frequently caused by Carbon buildup binding the intake manifold swirl flap runner plates or Broken plastic IMRC actuator linkage rod or vacuum diaphragm.

Where is the OBD-II port located on my Mercedes-Benz G-Class?

On the Mercedes-Benz G-Class, the 16-pin DLC diagnostic connector is located Driver side lower knee panel behind OBD door. Plug in any standard OBD-II scanner with the ignition in the ON position to read freeze-frame parameters.

Can I safely drive my Mercedes-Benz G-Class with code P2004?

Yes. Low-end engine torque will feel sluggish, but vehicle is drivable. Given that P2004 carries a Medium severity rating, we advise avoiding heavy towing or aggressive throttle inputs until sensor readings are verified.