Gen 2 4EATs apparently have only one replaceable sensor part, the entire trans wiring harness including 3 sensors and all the connectors that go inside the pan.

 

I need to replace my rear vehicle speed sensor, wondering if anyone has ever done the splice job and just replaced one sensor.

have done some trace the wires back to the conector and unpin them from it then you can change it out as a unit without a splice. I have a few of those harnesses out and have fixed that before

I was looking at the connector trying to figure out how to back the pins out, but didn't see anything obvious.

 

What's the trick?

 

Grab that white thing with some pliers and pull it out. Then you can get at the lock tabs on the pins with a flat head precision screwdriver or other small pointed tool.

Thanks. A day spent combing teh internets (nasioc, etc, man, those nasioc guys love to rebuild harnesses!) gave the same advice.

 

I'm going to spend some time on it tomorrow, maybe I'll just spot a broken or pinched wire and it'll be an easy fix. (It's never an easy fix, is it?)

have done some trace the wires back to the conector and unpin them from it then you can change it out as a unit without a splice. I have a few of those harnesses out and have fixed that before

 

Have you seen a common type of failure? Broken wire vs shorted by chafing vs just a bad sensor?

CNYDAVE call me if you need some help Ilive in SUMMER HILL 13154962093 STEVE `

not many speed senser problems mostly pinched wires or shop damage i do see the senser get wiped out when the pinion fails and alows the pinion to shuttle back and forth any meatal bitts on the end of senser will mess up its signal. should be able to contunuity check the senser harness or see its pattern on a vantage. I dont think iv'e seen a senser just fail randomly always a reason for it

CNYDAVE call me if you need some help Ilive in SUMMER HILL 13154962093 STEVE `

 

 

You're like 6 miles away so you should just drop by tomorrow afternoon (I'll be working from home and working on the car).

 

S on Salt, L on Stevens, tan house brown roof with the silly big garage behind it, used to be Gilbert's machine shop.

not many speed senser problems mostly pinched wires or shop damage i do see the senser get wiped out when the pinion fails and alows the pinion to shuttle back and forth any meatal bitts on the end of senser will mess up its signal. should be able to contunuity check the senser harness or see its pattern on a vantage. I dont think iv'e seen a senser just fail randomly always a reason for it

 

Hopefully the removers at the junkyard pinched a wire or such, if the old sensor comes out with metal bits on it or is mangled, indicating an internal problem, I'm going to be quite depressed. But, it's the rear VSS, so at least it would (tend to) be a tailhousing-accessible problem.

Trans connector, pins 19 and 20 on the bottom left.

Edited February 5, 201313 yr by CNY_Dave

these sensors are really simple and they do not fail very often. so before i cut any wire or tore apart any connector i would do everything i could to confirm that it is bad.

 

it makes sense that it could ba a bad wire, or connector.

 

and if i understand correctly, you do not have a flashing AT Temp light. if this is correct, then i do not think the rear speed sensor is in fact the problem.

 

however, i'm just playing the odds. and i tend to be very conservative and think that every problem is the most common problem. obviously this is not always the case.

 

but the VSS 1 fails ''10 MILLION'' times less often than the VSS2. (exaggeration intended.) i don't think i remember ever hearing of a rear sensor failing.

 

be sure before you cut.

Edited February 5, 201313 yr by johnceggleston

Oh hellyeah, I am going to check the snot out of it as far as possible before attempting to fix or replace anything.

 

Yeah, no flashing AT light, but a clear-as-day code 93 from the gerblinky-blinky AT temp light when put into diagnostic mode.

 

I even snagged a video of it so I could be sure.

 

This was a junkyard trans, it wouldn't be that hard for the yard guys to have hit the sensor or pinched a lead.

 

I did have to straighten the ATF dipstick tube by a fair amount.

remember, you already have a parts trans.

any luck ? had a blown awd in a svx yesterday the speed senser and matal chunks and peices on it was very badly blown had to replace the whole tail shaft and rear output assembly. Was able to do it in car what a mess glad i have many cores for parts. Got ruined from runing two diferent size tires front to rear

I'm working from home 3 feet from the car, chipping away at both.

RVSS at the trans connector (and the FVSS) ohm out just fine, wonderful.

 

Either it's intermittent or there's a prob in the harness between the connector and the TCU, and the problem was just a coincidence.

 

Joy.

Female pins on B11 to the TCU through the wiring harness is 60-160 kohms (depending on polarity) going to the FVSS input on the TCU, and mega-ohms for the RVSS. So looks like it's a harness-side not trans-side issue.

Harness checks out OK. 0 ohms (0.1 or so) for each lead between the TCU connector and the connector to the trans.

 

All the other diagnostic branches suggest it's either an intermittent or the TCU, as if a scope or the SSM or an AC voltmeter show no signal, it's ruled an either an intermittent or a bad TCM.

 

Would be funny if the TCM decided to go kaput right when swapping the trans.

Well, all that measuring and probing and leaving the batt disconnected, no more TCU codes but also no change in the AWD.

 

Since it seems to have a tiny bit of binding in a full-lock turn but no AWD I'm going to guess the clutch pack was abused and is no good, but I still can check the duty C solenoid, somehow.

Well now.
Well now, looks like '04 had the reversed functionality for the Duty C solenoid.

 

FWD fuse in place results in the transfer clutch being locked.

Ain't this special.

This also explains why I was getting what felt like binding while doing small circles at min throttle, and why I sometimes get a 'clunk' from the rear when turning the key off (it's the rear driveshaft 'relaxing').

So, does this mean I need an '04 TCU? An '04 TCU and ECU?

Do I need to make a manual duty-cycle control?

what is the trans id code on the bell housing?

 

a long time ago i heard something like this on JDM auto trans. but it was a long time ago and only one report so i didn't really take it seriously.

but i guess it could be.

Subaru says 'your best bet is to just use another transmission', no info avail on if the change is confined to the valve body or the extension housing.

tHE BEST INFO IS THAT NO ecu FLASH CAN FIX IT, AND THE '04 tcu WOULD REQUIRE CHANGING ALL THE OTHER VEHICLE CONTROL MODULES (oops, caps-lock stuck).

 

Looks like I will be either 'inverting' the duty-c signal (although low duty cycle won't neccesarily translate into the proper high-duty-cycle signal), or I'll be fabbing my own manual control unit.

 

John, the new trans has ID TZ1A4ZMFAA-M7, don't have the old trans number with me.

The odds of a 4EAT 2004 swap into a 2000-2003 (or vice-versa) is pretty low, so it's not surprising it hasn't been seen as a problem.

 

It clearly is the case though that the duty-c signals are bass-ackwards.

Its funny, I google that trans code and I only get hits in Germany and Russia.

Do you have torque bind if you unplug your TCU? If not, that would be a final confirmation it's backward.