Hi there,
I am new to the forum, however I have read tons of various forums for quite a few weeks now. I recently got a 95 Toyota T-100 3.4L V6 4x4 Auto. It was a little rough and needed some attention. With the help of some write ups I have replaced the timing belt, tensioners, water pump, and cam seals. Also I have cleaned my MAF, IAC and TB. Replaced ECU coolant temp sensor. I also replaced my rear wheel bearings and changed the seals. Changed both differentials oil and replaced the brake master cylinder and rear shoes and wheel cylinders. I also welded a pretty cool tailgate up that I can post pictures of later, only cost $50! Tightened all loose bolts and have been trying to get everything that rattles, to not. Anyways so it evident I am trying to get this thing running well.

Here is where the story gets TERRIBLE! I decided to install an aftermarket stereo into the thing. I noticed there was a factory amp in there, so I yanked it out, and cut off the plugs and soldered on all the proper connections. I had the battery disconnected the entire time. When I hooked the battery back up, the stereo would cut out and didn't sound all that great, the accessory wire only has about 4 volts? It was a used head unit so maybe it was already messed up. But here is the worst part. I started my truck up and a bunch of stuff wasn't working. It fired up and ran, but the tachometer didn't work, the heat shot up through the roof, the gear selector didn't show which gear it was in. And I could get it to go into gear and drive but it wouldn't shift out of first.
I am half decent with mechanical stuff, is something rattles or squeaks or doesn't feel right I will hunt it down and fix it. Electrical is NOT MY FORTE. So I am at a complete loss at what I could have done. Could I have fried my ecu? Would the car even run with a messed up ecu? Or does the factory amp act a link between two power sources as there are about 3 or 4 wires I didn't use when hooking up the head unit. Anyways if any of you have any guess at all where to start or an attempt to diagnose it would be very helpful! I went out and bought an OBD2 reader, and I am going to hook it up tomorrow and see what is says. Oh and I did disconnect the battery again for a couple hours to try and reset the ecu but it still had the same problem. Any help will be appreciated, thanks!
-Andrew

 

No doubt in your cutting off the harness you did something.

Why did you not just get a plug to wire your radio into the vehicle.

Best bet is to get a copy of the EWD for your truck and figure out just what you did.

 

Hi There,
I checked with a code reader today and it was P1780 which is a PNP sensor malfunction. Is it possible that it might not be the sensor itself but the gauge cluster? Maybe I managed to fry something in the cluster and the vss? The tachometer doesn't work and when I turn the key to accessory the P for parking illuminates, the when I turn the truck on it goes out, but if I put it into drive the D illuminates. Any ideas? Should I just change the PNP sensor? It is like $250...

 

Like Wyoming just said ^^^, get the EWD/Schamatic/FSM, and verify that the PNP sensor is indeed the problem before spending that money on something that will not solve your problem.
Spending mopey on guesses will not get you out of newbie mode- only make you a few bucks poorer
And tackle only one problem at a time, not jump from idle to wheel bearings to tailgate, to stereo...

 

What are you talking about? I have already done all that stuff, there stereo was one of the last things on my list... And replacing a timing belt and pressing bearing and retainers and abs rings off and on the axles is hardly the newbie zone?
I agree though that I am terrible with electronics, and yes I will look into the EWD and FSM I was simply looking for some sort of direction if anyone had any suggestions