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Tacoma with P0500 code and spedo not working

Maintenance/Repairs
#1

I am new to working on a Tacoma so I just want to run this by the experienced folks here and get their comments.

This is a 03 Tacoma with 4WD, Auto Trans and V6 engine. The speedo stopped working a few days ago and codes P0446 and a P0500 were pulled. No shifting problems were noticed.

The P0500 is the A sensor on the output speed sensor.
The P0446 is an evap system issue.

I found the speed sensor on the rear right side of the transmission and noticed one of the three wires is broken. The Blue wire specifically.

The connector alone is not available…or at least I could not locate it and ordered the entire wiring harness assy from the dealer. This assy connects to 2 or 3 other sensors or terminals.
The harness assy goes to the top of the transmission and i loose sight of were it goes from there. It was even too hard to feel around with out removing stuff.
My questions are these:

Is it much easier to cut out the good connector and splice it in place verses a potential struggle to remove and install the new factory wiring harness assy as intended?
Once it is installed and IF the problem is NOT solved…should I expect the VSS be the next logical part to replace? Since it is shifting ok should I assume the sensor is working.

#2

I’d just patch the broken wire. Be sure to use the correct crimp connectors and wire. There are lots of youtube videos available.

You could use the twist and tape method for a temporary fix to see if that solves the problem, but go back and do it correctly later.

#3

If the wire exiting the connector is broken where you can see it… and it WAS because you posted that. Just fix the wire.

Strip the insulation and any wrap tape back far enough to expose bare wire on the blue lead. If the wire is still sealed as it goes into the connecto, don’t bother replacing the harness end. My preferred way to fix it with an un-insulated crimp connector and shrink tubing over the whole repair to seal out water. Test it, then tape up the leads. If the blue wire is no longer sealing as it enters the connector, cut the pigtail end off the harness you bought about 6-8 inches back and do the same to the one on the car and connect as I described before.

If that doesn’t fix it, sure, the VSS may be the issue but don’t get too far ahead of yourself. Fix what you can see first.

#4

Thanks for the replies. I was not clear but the blue wire is broken right at the connector. There was also a dired RTV like substance all over the top of the connector. I am assuming this is not from the factory and someone did this to fix a problem at one time. I know some connectors can easily be disassembled and put back together but it looked difficult on this one. If I could have easily taken the harness assy off the vehicle and worked on a bench, maybe I would have been more confident in doing this The potential of RTV making it harder to disassemble, time slipping away and being on my back and with limited space. I decided not to mess with it anymore and get a new one.

It looks like at least one endorsement for cutting the connector off the new assy and splicing. I have some wirenuts on hand and some insulated crimp connectors that I could still use shrink tubing on. I am thinking the wire nuts back filled with RTV may be faster and equally reliable.

#5

You are thinking wrong! NO! Wire nuts are for stationary wiring, not wiring that bounces around in a car or truck. Do not do that!

Insulated connectors back filled with electronic grade RTV would be preferable but un-insulated connectors with shrink tubing are better so why not spend a few dollars and do it correctly?

2 Likes
#6

Can’t speak directly to this problem, but I had a wire break right at the connector surface on my Corolla, the circuit which powered my trunk-lid license plate light. No surprise there, it is flexed whenever the trunk lid is opened and closed. I cut off both sides of the connector leaving bare wires, spliced in some spare stranded wire of the same awg to make the service loop a little longer, and soldered and shrink wrapped it all back together. No connector at all. Been working fine. The connectors are helpful during manufacturing b/c the sub-assemblies can be made independent of the rest of the car, then everything connected together , made fast by using the connectors. But if there’s no particular reason for a connector to be there, I don’t see any reason why they just can’t be removed if they are causing problems.

1 Like
#7

Update. the dealer had the wrong part. The correct wiring harness assy is $1400. Yes, that is not a typo. They did offer a new connector repair kit for around $32. Which is what I was looking for in the first place. I did order it.
if I could easily make it to a junk yard that would be the best solution. but right now it is not a viable option.

#8

Best of luck. A $32 fix seems like a good plan.