Fox Ecm Swapping


Active Member
Nov 23, 2011
SF Bay Area
I plan on changing out my ECM to an A9L soon from what i currently have (which is an A9P), other than making sure i have the correct O2 harness, is there any special process in doing the swap? Im assuming disconnecting the battery is the first thing to do....anything else in particular i need to do or is it a very straight forward remove and replace? thanks guys. yes i have a manual trans and manual trans harness btw.
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I didn't really have an issue with the stink...
SN Certified Technician
Mar 2, 2015
Very straight forward remove and replace.

Remember to pull the jumper out of the clutch switch plug and plug it into the clutch switch. It helps the computer sense when the clutch is pressed for proper idle strategy and to hang rpms while changing gears. Also, it allows the car to start only when the clutch is pressed in. Here's a pic from Google. Both plugs need to be plugged in.


There's also a difference in the transmission harness that goes from the drivers kick panel, under the drivers seat, and through the trans tunnel. There's been some debate over this harness. I replaced mine with one from a 5 speed fox. Connector pin position may have varied through the years. Mine came out of a 1989 and fit a 1988.

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