I have a manual transmission 96 xj, it runs fine with an automatic ecu in it, but I get a p1899 code for not having a neutral safety switch in it. Has anyone successfully tricked an automatic ecu into not throwing this code running a manual transmission? Is it as simple as wiring a switch to the ecu to fool it into thinking its in park or neutral on start up and flipping it to think its in gear before driving? Id like to see if anyone has done this before i go ahead and fry a good ecu messing around. I have a factory repair manual so I'll be able to identify the correct wiring and circuts i need to work with. Reverse lights work, starts up and runs fine, have driven it without any other issues or codes for a few weeks. Shift light comes on consistently, but im thinking thats from it not knowing whether its in drive or park. Thanks for any help,

 

Seems like jumpering the NSS connector so the ECU sees park should work. Easy enough to try right?

 

Yes, you can trick it. Jump the right pins at the NSS connector to tell the ECU it's always in Drive/Neutral. Look up the pinout for your automatic NSS plug in your manual. It's not one simple switch, you need to connect specific circuits. Do not short power to ground. People do this swap all the time. Search Cherokee forums for "NSS bypass manual swap" for the exact wiring. Don't worry, you won't fry the ECU if you just connect the signal wires correctly.

 

In theory yes, but wouldn't it also need to register as being in gear while driving so it doesnt think its in neutral/park while driving? It starts right up so something is jiving to register it in neutral/park for start up. It doesn't have a clutch switch, I guess ill need to figure out the logic the ecu uses to trip the code. Might be as easy as a switch in the nss circut. Was kinda hoping to hear from someone who's done it before. All the searches I've tried come back to renix or later models. The 96 is its own monster.

 

Not doing a manual swap, technically im doing an ecu swap. Vehicle is manual from the factory. All searches lead to manual swapping and auto, none of them for a 96, I looked already. Im looking for some insight from someone who's done this or knows enough to confirm how to do it.