Reverse Lights Stay on, PRND2L Always Indicating In Revers, Trans Not Shifting Properly (1 Viewer)

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So I recently changed my spark plug wires on my 1993 FZJ as well as doing the dreaded PHH replacement yesterday. When I was done replacing the PHH I went on a test drive to make sure I had no leaks and it was good. However I noticed that when I got on the gas the engine would rev up slowly and it felt like it had no power. The check engine light also came on. I later discovered that if I shifted into Low it would stay in low until I manually shifted into 2nd. If I tried to shift it from 2nd into drive to get into 3rd/overdrive nothing would happen and it would stay in 2nd. If I were to stop and start out in Drive it would stay in 3rd and not downshift to get on the move faster. That same day I took it to the dealer to see if they could diagnose a problem and they said that it could be a bad knock sensor (this was the only code they got from the check engine) but I believe this may be irreverent to my problem.
 
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So I also thought it would be the trans shift solenoid. However most everything I read about other people's shift problems and they all looked to be getting worse over time. My problem was a sudden onset because when I drove it less than a week prior everything was as it should.
Considering you just did work on the PHH, I'm guessing you jacked with a plug on a wiring harness down there that affects the transmission shift solenoids.
 
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Considering you just did work on the PHH, I'm guessing you jacked with a plug on a wiring harness down there that affects the transmission shift solenoids.
Hmmm I agree. Ill have to check it when get it back from the dealer. Ill see what I can find.
 
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Okay so. I looked at where I was working when I replaced the PHH and I didn't find any lose connections or unplugged plugs. However I realized that my reverse lights are always on as well as the reverse indicator on the gauge cluster (reguardless of what gear im on). I have a theory that maybe my ECU is thinking that I am in reverse when im actually in a different gear. Does anyone know of this sort of problem or how to fix the gauge cluster?
 
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The dash tally lamps and reverse lamps are driven from the neutral start switch. That also tells the ECU what gear you're in according to the position of the shift lever.
I don't have the manual for a 1993, but I would suspect that there is a faulty connection to the NSS.
 
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The dash tally lamps and reverse lamps are driven from the neutral start switch. That also tells the ECU what gear you're in according to the position of the shift lever.
I don't have the manual for a 1993, but I would suspect that there is a faulty connection to the NSS.
Thank you for the insight, ill check it out in the morning when I have more light.
 
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I believe there is a harness with a plug that runs under or near the PHH that connects to the NSS. Possible coolant leaked on it when you changed the hose?
 
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As others are mentioning,
The NSS grey barrel connector is the problem. Wires are corroded. Get to the bad ones and wire around the connector. Also make sure your inner fender liners are in place. If not make some from an 18 wheeler mud flap. Super cheap and easy to do.
 
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As others are mentioning,
The NSS grey barrel connector is the problem. Wires are corroded. Get to the bad ones and wire around the connector. Also make sure your inner fender liners are in place. If not make some from an 18 wheeler mud flap. Super cheap and easy to do.
Sounds like a plan. Ill look at the NSS barrel connectors to see if there is corrosion (today I just checked if they were plugged in all the way and they were). It would make sense since the PHH leaked a ton when it broke. Also, are there 2 models of NSS? I see pictures of It with a rectangular connector that attaches directly to the unit and then I see one that has said barrel connectors. I'm guessing that the one with the barrel connectors needs the entire unit to be switched out? And my fender liner seems to have been removed long before I've owned it so imma defiantly make new ones.
 
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No need to replace the NSS unit at this time. Failure point is most likely the connector under the PHH. Just unplug, be careful and note what colored wires go where. Seems like there’s about 7 wires. I did one that had two bad wires. Bad ones can be spliced around connector or if you’re really anal, source two new connectors, cut all wires and install. Chances are you will never need to unplug connector.
 
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So today I decided to replace the broken Knock Sensor and check out the NSS to try and figure out what might be causing me problems. The knock sensor didnt do much to help (to no suprise) however I found out the I may have a HUGE problem. The connector that connects the NSS to the wiring harness was completely fried and I dont know what im going to have to do to fix it. Both the female and male ends are burnt black. Here are some pictures. The closer one is of the NSS side and the other is of the engine side.

20200507_173029.jpg


20200507_173106.jpg



Does anyone know what I may have to do to fix this? I really dont want to have to replace a harness
 
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You sure they are burnt black? I can't tell if they are damaged in those pics though I do see old dialectric grease that has done it's aging thing and may be making things look worse than they actually are. Try to clean them out and then take/share more pics if you can.
 
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You sure they are burnt black? I can't tell if they are damaged in those pics though I do see old dialectric grease that has done it's aging thing and may be making things look worse than they actually are. Try to clean them out and then take/share more pics if you can.
All of that brown/ black stuff is burnt and melted plastic. And in the engine side connector there is a pin that is stuck in the middle port. I can try and clean out the female end to include pulling that connector and try plugging in a new NSS but I cant say if it would work or not.
 
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Ouch, I couldn't tell and am not familiar with the pin configuration of that plug. Hopefully the damage is limited just to the socket/plug and a result of issues there vs. circuit overload that also damaged wires. I'd still clean it out as it will make it easier to disassemble and inspect further which seems like the next step to assess how much you need to replace.

Hopefully you just need new new parts to rebuild that connection and not any wire repair.
 
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Ouch, I couldn't tell and am not familiar with the pin configuration of that plug. Hopefully the damage is limited just to the socket/plug and a result of issues there vs. circuit overload that also damaged wires. I'd still clean it out as it will make it easier to disassemble and inspect further which seems like the next step to assess how much you need to replace.

Hopefully you just need new new parts to rebuild that connection and not any wire repair.
Yes the damage looks to be just the socket it self because the wires behind it apeare to be fine. I fairly certain that the damage is only in this area and nothing concerning the ECU is damaged. Im going to try and clean out the socket and get a new NSS to plug in to see if it fixes anything. If it dosnt then looks like I may have to splice a new female end into the harness which will be a pain in the butt being that there is no room in there for tools let alone hands.
 
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So today I decided to replace the broken Knock Sensor and check out the NSS to try and figure out what might be causing me problems. The knock sensor didnt do much to help (to no suprise) however I found out the I may have a HUGE problem. The connector that connects the NSS to the wiring harness was completely fried and I dont know what im going to have to do to fix it. Both the female and male ends are burnt black. Here are some pictures. The closer one is of the NSS side and the other is of the engine side.

View attachment 2299097

View attachment 2299098


Does anyone know what I may have to do to fix this? I really dont want to have to replace a harness
Since I’ve been there you have to keep telling yourself you can do this. Long skinny arms/hands help and so does a bright magnetic flashIight. I would map out and label each connector wire. Cut and splice one wire at a time around the connector. Heat shrink tubes on each wire splice would also be recommended. It’s definitely something you will never forget doing but when done you’ll say that wasn’t really that bad.
 
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Since I’ve been there you have to keep telling yourself you can do this. Long skinny arms/hands help and so does a bright magnetic flashIight. I would map out and label each connector wire. Cut and splice one wire at a time around the connector. Heat shrink tubes on each wire splice would also be recommended. It’s definitely something you will never forget doing but when done you’ll say that wasn’t really that bad.
Fixed the problem. I got a new NSS and cleaned out the engine side plug. I managed to get them to mate properly and it solved all the problems instantly. Just wanted to say thanks to everyone who helped me out to resolve this issue and I can drive my beloved 80 again.
 

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