[isturg]

I currently have a JB3 chip in my car and want to upgrade to the JB4. Do I need to buy the whole thing, or just the chip? Thanks

[enrita]

email BMS , i guess you need to replace the harness as well but you might get a better price if you send the whole thing back to them.
and its not a chip... its a piggyback

[Jeff@TopGearSolutions]

There is a Jb3 to JB4 upgrade available directly from BMS and Dealers like ourselves:
http://www.burgertuning.com/JB4_upgrades.html

[Sered]

Originally Posted by isturg

I currently have a JB3 chip in my car and want to upgrade to the JB4. Do I need to buy the whole thing, or just the chip? Thanks

If you've got the pinout harness (and not the newer PNP harness) then it's a mild pain. To convert from a JB3 to an older JB4 requires moving wires around a bit since the JB4 functions differently, etc. Going to a JB4 G5 (the new one) requires a few more pins, but not too big of a deal. Pretty easy once you have the harness maps and there's plenty of info on how to do it.

The BEST thing to do is to get the JB4 G5 upgrade ($150) and buy the PNP harness ($180 with $130 core until you return the old pinout harness). That would involve removing the JB3 and converting it back to stock (annoying); then installing the PNP harness (which is extremely easy). This is what I did, except I upgraded from a AA AP2 to JB4 G4 then just recently to a JB4 G5 ISO.