Check engine light with - P1078 code

MONDRAGON

MEMBER
2006 HONDA CRV
4 CYL
4WD
MANUAL
150,000 MILES

I get the P1078 code. I brought it to a shop and they have replaced the IMRC and the solenoid as well and the check engine light is still on. Not sure what else to do.

Friday, February 2nd, 2018 AT 11:53 AM

6 Replies

KHLOW2008

MECHANIC
41,815 POSTS

Hi Mondragon,

When codes are present, it does not necessarily mean that a component has failed and replacing them would solve the problem.

Solenoids are electrical components that are commanded by the engine control unit and if there is a fault with the wiring such as a broken or loose wire, the system would fail.

The solenoid is to allow or cut off vacuum between the manifold and IMRC. A fault with the vacuum lines (clogged, kinked or leaking) would result in problem as well.

You should start checking with the two mentioned above, i.E. Wiring and vacuum.

KH Low

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Saturday, February 3rd, 2018 AT 1:00 AM

MONDRAGON

MEMBER
6 POSTS

Thank you for the reply. The mechanic is suggesting I buy a new exhaust manifold because he said there might be a small crack on it. Do you think that could cause that code? I will check the wiring as you suggested. As for the ECU, how can I check it? The only way would be to replace it correct?

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Saturday, February 3rd, 2018 AT 7:26 AM

KEN L

MASTER CERTIFIED MECHANIC
42,883 POSTS

I do not think an exhaust manifold will cause a problem with the IMRC.

Here is some good information:

Note:
When installing the IMT actuator, make sure the bearing (D) is in place.
Make sure the IMT assembly does not interfere with the intake manifold (E).
When installing the IMT actuator, replace the O-rings (F).

Apparently you must install the IMRC a certain way. Here is a guide to help you see how to check the wiring:

https://www.2carpros.com/articles/how-to-check-wiring

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

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Monday, February 5th, 2018 AT 11:54 AM

MONDRAGON

MEMBER
6 POSTS

Thank you Ken. I ordered the part from Honda and the the entire rotary valve assembly comes with those O-rings. It also comes with a clip to hold the IMRC in the position it is supposed to go into the intake manifold. When you are going to install it you just remove the clip and it fits right into where third image you posted shows. I spoke to the mechanic yesterday and told him about the possibility of the faulty wiring. He told that was one of the first things he checked and he is kind of stumped on this one because he’s gone through the steps that have been suggested here. He clears the code and the light goes away. But it comes back after running the car for about 20 minutes and restarting it a couple of times.

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Tuesday, February 6th, 2018 AT 8:07 AM

KEN L

MASTER CERTIFIED MECHANIC
42,883 POSTS

Is the inside of the intake manifold clean? I an wondering if something is stopped the valve from working such as a collection of the coking inside the manifold. If all is clear and the wiring is okay I would say the ECM is having a problem.

Here is its location you will need to have it programmed.

Check out the diagrams (Below)

Please let us know.

Cheers, Ken

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