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View Full Version : L56 to L65 pcm



DILLIGAFRI
09-28-2011, 05:47
Tired of dealing with the 400 and 401 codes from the egr being plugged and also because in RI they no longer sniff the exhaust, just read the codes for inspection. Always passed fine when they sniffed but now with reading codes I have failed. Question is can I swap a L65 pcm for the L56 and is it plug and play or is there programing involved? Option 2 is a reflash that I have read about here on my current PCM. Any idea on cost to do this?
Thanks in advance
Dave

1998 K1500 L56 egr motor

DmaxMaverick
09-28-2011, 06:20
A PCM swap or reprogram will work. While a L65 PCM would be ideal (if you want to keep stock trim), there may be a problem with smog inspections if they plug in to the truck, the VIN won't match. In CA, if the VIN doesn't match, the test is rejected.

If this is the case in RI, and the EGR is mechanically disabled, you may have only one option, a reprogram. If you've only disconnected it, you may have to reconnect for inspections. You could also have 2 PCM's, and swap in one that works for inspections during that time (what most do around here).

Kennedy
09-30-2011, 06:46
We do this all the time with Custom ECM programming and I seriously doubt you will get checked for EGR. They'll look for Catalyst shell, DTC's, and probably smoke/opacity would be my guess.

DaveBr
09-30-2011, 22:08
I have done this on my truck. Get an intake manifold from a 3/4 ton and change it out with your existing one. You will see the diff between the two right away. Bolt your EGR valve right onto the top of the new upper manifold. There is no hole for EGR but the bolt pattern is the same. Your EGR is intact but inoperable. Looks good for a visual check.

Take your MAF sensor apart and remove the honeycomb and anything else that will restrict air flow. Put it back together. Looks good for a visual but is inoperable.

Get a used ECM from an F code engine - same year to avoid headaches and make sure it matches your tranny, auto or standard. Change it out and you are good to go. You will also notice a horsepower increase.

Make sure your air filter is clean as your engine will suck a lot more air now. Any questions? Don't hesitate to ask. Good luck.