Land Rover OBD-II Trouble Codes
-------------------------------------------------The diagnostic trouble codes (DTCs) P2004, P2005, P2006, P2007, and P2008 all relate to issues with the Intake Manifold Runner Control (IMRC) system. These codes specifically indicate that the control for the intake manifold runner is either stuck open or closed. Additionally, these codes may specify whether the issue is on Bank A or Bank B, depending on the engine configuration.
Intake Manifold Runner Stuck Open,
Intake Manifold Runner Stuck Closed,
IMRC Actuator Performance,
Bank 1 & 2 Swirl Control,
Variable Intake Geometry Fault,
Diagnostic Overview
The System: These codes indicate that the Intake Manifold Runner Control (IMRC) flaps are physically not in the position the PCM commanded. Unlike the previous electrical codes, these are mechanical performance faults.
P2004 / P2005 (Stuck Open): The runners are stuck in the "high speed" position. This often causes a loss of low-end torque and a rough idle.
P2006 / P2007 (Stuck Closed): The runners are stuck in the "low speed/swirl" position. This causes the engine to "choke" or lose power at higher RPMs.
P2008 (Circuit/Open): This is the control circuit code for the entire Bank 1 runner system, often indicating the actuator itself has failed or is disconnected.
Common Failure Points
Carbon "Coking": This is the most common cause. Oil vapors from the PCV system mix with soot from the EGR system to create a sticky "sludge" that glues the flaps to the intake walls.
Broken Plastic Linkage: The arm connecting the actuator motor to the runner shaft is often made of plastic. If the flaps are slightly stuck and the motor tries to move them, the plastic arm will snap.
Vacuum Diaphragm Leak: On older systems that use vacuum to move the runners, a tiny tear in the rubber diaphragm will prevent the arm from moving, even if the solenoid is working.
Internal Manifold Wear: In some designs (like Ford or Chrysler), the bushings holding the long runner shaft wear out, causing the shaft to tilt and bind against the manifold housing.
Troubleshooting Steps
The Manual "Feel" Test: Locate the linkage on the side or back of the intake manifold. With the engine off, try to move the arm by hand.
If it's loose and floppy, the linkage is broken.
If it’s rock solid and won't budge, the flaps are carbon-locked.
Vacuum Test (If applicable): If your actuator is a round vacuum "pod," use a handheld vacuum pump. Apply vacuum; the arm should move and hold position. If it slowly retreats, the diaphragm is leaking.
Cleaning Attempt: Some technicians have success spraying intake-safe cleaner into the manifold while the engine is running to break up the "gunk," but for severe cases, the manifold must be removed and manually cleaned.
The "Zip-Tie" Trick: For diagnosing P2004 (Stuck Open), you can sometimes manually zip-tie the linkage shut. If the idle smooths out, you’ve confirmed the flaps are the issue.
Would you like me to see if your specific engine has a known "repair kit" for the linkage arms so you don't have to replace the whole manifold?
Diagnosing P2004 and P2006 IMRC Codes
This video demonstrates how to locate the IMRC actuator and how to determine if the "stuck" condition is due to a failed vacuum solenoid or a physical blockage inside the manifold.
Here's a breakdown of each code:
1. **P2004 - Intake Manifold Runner Control Stuck Open (Bank 1):**
- This code indicates that the IMRC system on Bank A (cylinder bank 1) has detected that the intake manifold runner control is stuck in the open position.
2. **P2005 - Intake Manifold Runner Control Stuck Open (Bank 2):**
- Similar to P2004, this code indicates that the IMRC system on Bank B (cylinder bank 2) has detected that the intake manifold runner control is stuck in the open position.
3. **P2006 - Intake Manifold Runner Control Stuck Closed (Bank 1):**
- This code indicates that the IMRC system on Bank A has detected that the intake manifold runner control is stuck in the closed position.
4. **P2007 - Intake Manifold Runner Control Stuck Closed (Bank 2):**
- Similar to P2006, this code indicates that the IMRC system on Bank B has detected that the intake manifold runner control is stuck in the closed position.
5. **P2008 - Intake Manifold Runner Control Circuit/Open (Bank 1):**
- This code indicates a circuit or electrical issue related to the IMRC system on Bank A.
### Possible Causes:
1. **Stuck IMRC Valve:** The intake manifold runner control valve may be physically stuck in either the open or closed position.
2. **IMRC Solenoid Issues:** The solenoid responsible for controlling the IMRC valve may be faulty.
3. **Wiring or Connector Issues:** Problems with the wiring or connectors associated with the IMRC system.
4. **Vacuum Leaks:** Leaks in the intake manifold or vacuum hoses can affect the operation of the IMRC system.
5. **Faulty IMRC Actuator:** The actuator that moves the IMRC valve may be malfunctioning.
6. **Carbon Buildup:** Accumulation of carbon deposits on the IMRC valve or related components.
7. **Faulty Intake Manifold Runner Control Module:** Issues with the control module responsible for managing the IMRC system.
### Diagnostic Steps:
1. **Inspect IMRC Valve and Actuator:** Check the physical condition of the IMRC valve and actuator for any signs of sticking, binding, or damage.
2. **Test IMRC Solenoid:** Test the IMRC solenoid for proper operation. Replace if necessary.
3. **Check Wiring and Connectors:** Inspect the wiring and connectors associated with the IMRC system. Look for any signs of damage, corrosion, or loose connections.
4. **Verify Vacuum Levels:** Check for vacuum leaks in the intake manifold and vacuum hoses. Address any identified leaks.
5. **Perform Carbon Cleanup:** If carbon buildup is suspected, consider cleaning the IMRC valve and related components.
6. **Test IMRC Module:** Test the IMRC control module for proper operation. Replace if necessary.
7. **Clear Codes:** After addressing any identified issues, clear the trouble codes and monitor the system for recurrence.
8. **Consider Professional Assistance:** If you are unsure about diagnosing or addressing these issues yourself, or if the faults persist, it's advisable to consult with a qualified mechanic or technician.
Addressing the root cause of the IMRC system faults is crucial for proper engine performance and emissions control. If in doubt or if the faults persist, seeking professional assistance is recommended for a thorough diagnosis and effective repair.
