IMRC circular crack problem found & fixed P1518

[bostonman]

I found a problem with the IMRC board and I think this could be a common cause of P1518 Check-Engine code.

Thanks to the write up of the following members and it was a great help in finding the problem and removing the IMRC module for repair (I don't even have the repair manual ! Any one has the eManual that can share? )
ST insane
SVT_ME
machslammer

This is what I found:

After I removed the IMRC with the instruction of the helpful links above. This is the IMRC circuit board:



The arrows are pointing to the problematic area on the other side of the board.

When you turn over:


Circular cracks found on the solder joints of the relay leads. They are pressed by the rotating cam every time you start the engine and when you rev >5000 rpm and back. Eventually the slight mechanical force is causing circular crack on the solder joints and created a bad electrical contact (weather/temperature dependent and that's why this problem sometime is intermittent )The cold Boston weather probably has contributed to the problem since cold solder joints are less flexible and might crack more easily.

Zooming in to the solder joints:




The same circular cracks from a different angle:



I used my beloved soldering iron to reflow the solder (with added fresh solder) on the joints and the problem was solved. It's been a week after my fix, no more P1518 and also have got my inspection sticker finally (I did drive my car for 85 miles after reconnected the battery and have enough time for the sensors to capture readings before the re-inspection).

This is not the first time I saw this kind of problem. This is a well known problem of Honda/Acura Main relay module. This is another DIY that I wrote fixing a similar circular crack problem in the Acura Legend forum (again circular crack on relay lead).

Happy fixing!
Tat

[sleepyboy]

Nice fix!!

[COSVT03]

Stick it - Has all the links needed - or add it so this is easily found.
Thanks to everyone that worked on this!

Good eyes.

[bostonman]

If you are not a soldering expert, you can learn some technique HERE.

[Sniper Focus]

Good to know! I've been soldering for a long time, so it should be a no cost fix if I get that code.

[SVT Mike]

Definately sticky or "how to" section worthy.

[Nileo2005]

I wonder if this is what is throwing my 1518. It seems to be temperature related. When its really cold out, it throws the code, but after a couple days of warm I'll start it and the CEL is magically cured.
...and will decide to re-emerge one freezing Ohio spring morn...

[bostonman]

Sounds like a electrical problem. I had similar problem... I had P1518 the whole winter but one warm spring day, I saw the code reset itself after startup. But it threw the code again the next day. I bet it is the "circuit crack" problem, or a bad relay contact inside on the board (the contact point pressed by the cam as in the other thread I quoted).

[Nileo2005]

Sweet. I'll have to crack that guy open and take a gander.

Do you think a small bit of dielectric grease on the contact would be a good idea to ensure the sensor doesn't not connect anymore? It looks like there is a fair amount of gap in that circuit when in the open position, so I couldn't imagine there would be a problem with the grease bridging the contacts when its not supposed to. But that may be just playing with fire when its not really necessary...

[bostonman]

The contact in my IMRC was shinny and I didn't even need to clean it.
The problem was the bad circular crack causing intermittent bad connection.
Make sure you seal the IMRC module with silicon when you put it back.

[stanger19899ddr]

This is a great post
My SVT was getting the dreaded IMRC check engine light when I found this post
Figured I would try to fix my module today after I retuned from the salvage yard.
I found a unique thing today I think
While I was walking around I found a duratec 24 valve engine it had the IMRC on top of the engine. I decided to look inside the IMRC Module I noticed it had the short cable. I think all The 99 and newer have the short cable.
Took the screws loose for the circuit board, Wiggled the connector and the circuit board and the motor are easily removed.
Turned the gear with the cable on it and the cable slid out. It even had the same number on the box as my 02 foocus SVT. You can clean the contact and whatever else you need to do and dont have to unsolder anything.
ALSO found out a 96 Contour duratec 24 valve V6 engines module is a direct replacement for the SVT. Just put one in mine and cleared the light
WORKS GREAT...

[qweesy]

very nice I was just about to refresh my IMRC anyway thanks for this, very similar to the old hondas and their fuel pump relay box all it needs is a solder reflow awesome bro