2004 Honda CR-V Intermittent DTC — P1077 IMRC

G Educator Mahopac, New York Posted   Latest  
Case Study
Driveability
TST - Technician Service Training
2004 Honda CR-V EX 2.4L (K24A1) 4-spd (MRVA)
MIL On
P1077 - Imrc System Malfunction (Low Engine Rpm)
Imcr

Hello everyone,

The above vehicle with 278,974 came in with an illuminated MIL that was coming and going. The vehicle owner had been in several times with the same P1077 IMCR (Intake Manifold Control Runner Valve Malfunction) DTC. This code was intermittently illuminating the MIL every now and then, but the owner never wanted it diagnosed. When it was time for a state inspection, the MIL was illuminated once again which prevented the CR-V from passing the OBD II emission test. Now the CR-V owner had no choice other than having the problem diagnosed and repaired if he wanted an inspection sticker. 

The first place to start was by performing a "look see" of the engine’s intake manifold (Figure 1) making sure that vacuum hose was connected and receiving vacuum. This was followed by making sure that the intake runner sensor was properly connected and reading the correct voltage. Since all our visual checks came up empty, we connected a vacuum pump and applied vacuum to the intake manifold diaphragm while checking the sensor voltage on the scan tool. After applying vacuum, a dozen or so times we found that the sensor was not reading the properly. I'd also like to mention that we did discover a TSB, 05-052 related to this DTC. The bulletin describes a sticking vacuum control solenoid valve which we didn't have.

The results of our test indicated that the internal runner was not always moving, or the sensor was defective. To make sure what part was defective we removed the sensor and manually moved it through the full range without finding any glitches. The next step was to remove the vacuum diaphragm assembly (Figure 2) where we uncovered an oil issue. Since we found oil in the manifold, we decided to remove the IMCA and captured a video so the vehicle owner was able to view the delay in its movement. With the intake manifold removed, (Figure 3) we checked and cleaned the intake ports that we found carboned up. 

The next step was to order a new (Figure 4) intake manifold that comes with a runner, diaphragm and sensor. The reason we recommended replacing the complete manifold was due to manifold warpage that caused the new intake runner to bind up. With the owner permission we installed the new manifold then test drove the vehicle home, so the OBD II Monitors would become "Ready" for inspection. 

Remember if you don’t want the "You Suck" light to illuminate, you need to make sure that all the Monitors are Ready. Now this CR-V with over 279K was now running good without the MIL being illuminated.

+10
Mark Mobile Technician
Arlington, Vermont
Mark
 

great case G i never knew they honda used IMRC in a 4 cyl the accord i dont believe has it

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Tom Owner
Ocean Township, New Jersey
Tom
 

Nice job G. My oldest son has exactly the same issue on his 04 CRV. I haven't gotten into it yet because we have been swamped with work that customers pay for, not Dad. State inspection is just around the corner for him so I will follow your in steps.

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G Educator
Mahopac, New York
G
 

Tom thanks for reading and commenting. The manifolds become warped when there are high miles on them. If it's a low milage engine then you can just change the IMRC. Let me know how you make out...Happy Easter

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