05 Speedo Question

As everyone may know I have a V8 under the hood of my 05. Love every minute of it; however, my speedo does not work. Here is how it is set up currently, 96 motor/harness/ecu, 98 4R70W 2wd trans, stock axle. Everything is plumbed currently for the wiring; however, with the CC connected my speedo does not work but with it disconnected it does work just does not kick on until 30 mph.

This has me scratching my head and pissing me off. Any suggestions would be greatly appreciated.

Speak with "Riq21", he has figured this out in his '02, it may be similar.

http://www.therangerstation.com/forums/showthread.php?t=111913

I posted in his thread but his last post in the thread back in Feb.

Where are you sourcing the VSS and where does that signal go next?

I spoke with Pete on this since he did the wiring. He said it is coming off the speed sensor on the back of the trans, then into the OSS, to the PCM and then to the cluster/CC.

hoosier1104 said:

I spoke with Pete on this since he did the wiring. He said it is coming off the speed sensor on the back of the trans, then into the OSS, to the PCM and then to the cluster/CC.

Click to expand...

That's different. I'm confused as to how it could work correctly connected to 2 speed sensors.

Here are other methods that could be tried:

• VSS directly from the transmission Signal Generator as in a stock 95~97 Ranger/Explorer 2WD. This assumes that the 98 tranny you are using has the port and drive gear for the SG like the earlier version did. If it is possible to install the SG, no conversion module would be needed for this method.
  
• Raw signal from a speed sensor on the transmission (if available and the right tooth count), and then through a compatible conversion module and out to the PCM, speedometer and cruise.
  
• Raw signal branched off from the rear axle ABS sensor and through a compatible conversion module and then out to the speedometer, cruise and PCM.

The last method is how I set mine up and RIQ21 used my info to get his working. This is for a 2001~2003 Ranger but it MIGHT also work with the digital odo cluster like yours.

Thanks man. When I get back down to Pete's to do my AWD, we will take a look at it.

I already have a converter for it, if necessary.

hoosier1104 said:

I spoke with Pete on this since he did the wiring. He said it is coming off the speed sensor on the back of the trans, then into the OSS, to the PCM and then to the cluster/CC.

Click to expand...

My bad, I misread the wiring diagrams. According to Mitchell, the 96 expo has a VSS sensor. The 05 Ranger does not have a VSS.

Per Mitchell: The output shaft speed sensor (OSS) generates and transmits the vehicle speed signal (VSS) data to the powertrain control module (PCM). The PCM sends the VSS data to the instrument cluster and all other systems that require VSS input. The instrument cluster, upon receipt of the VSS signal, commands the speedometer pointer to the corresponding position.

The signals are probably different between the two vehicles. Justin is supposed to have the adapter which generates the correct signal. We just need to install it and see what happens.

Pete

allnpt0 said:

Per Mitchell: The output shaft speed sensor (OSS) generates and transmits the vehicle speed signal (VSS) data to the powertrain control module (PCM). The PCM sends the VSS data to the instrument cluster and all other systems that require VSS input. The instrument cluster, upon receipt of the VSS signal, commands the speedometer pointer to the corresponding position.

Click to expand...

The above is true for the original Ranger 2005 PCM. The PCM acts as the conversion module and the cruise and speedometer use its output.

The 5.0 Ex PCM of 1996 (or any other year) is different. It does not have the capability to do the VSS conversion. The PCM is simply an "end user" just like the speedometer or cruise control.

So in theory, we could take the VSS straight to the cluster then w/o going to the PCM.

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hoosier1104 said:

So in theory, we could take the VSS straight to the cluster then w/o going to the PCM.

Click to expand...

Well, MAYBE, if the combination of parts is correct.

The 95~97 Rangers and Explorers used a Signal Generator on the transmission (2WD) or the transfer case (4WD). This is a gear driven device that fits into a port where a speedometer cable would have gone in earlier years. The SG outputs a 0~12V pulse that is directly readable by the PCM, cruise and speedometer. Adjustment for axle ratio and tire size is done by interchanging gears in the same fashion that one would have calibrated a traditional cable speedometer.

Now for the possible issues with the Signal Generator:

1) As I understand it, you are using a 98 4R70W transmission that did not have a SG installed from the factory. So, you'd have to determine if the SG port is still there and that there is a drive gear for it inside. If not, then you cannot use this method.

2) You have the digital odometer cluster in your 05. Will it accept the same 0~12v signal that was used in earlier years? I suspect that the answer is "yes" but, to my knowledge, no one has confirmed that by actually trying it.

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Any other sensor that you might use for VSS needs a module to increase the signal amplitude and correct the frequency for use by the speedometer, cruise and PCM. Over the years, RBVs have used the GEM, 4WABS Module or PCM for this conversion. The important thing is to use a module that is compatible with the input signal from the transmission, transfer case or rear axle. The most obvious way to do this is to mimic a complete system as used on another Ranger or Explorer. Adjustment to a system like this must be done through the Module Communication Network using a dealer tool.

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If an aftermarket speedometer calibration box is used instead of a factory module, it will likely have a much greater range of adjustment that would allow it to work with any of the existing factory sensors. Another benefit of this method for swappers is ease of adjustment - as a universal device, it is designed to be field adjustable, requiring no special wiring or dealer tool.

If I am understanding everything correctly, VSS is a analog (sine) wave and my cluster is a digital (square) wave. So the convert needs to go inline on the cluster circuit either in front of PCM before the main harness connection or just after the connection. I also have a module to correct the actual speed as well.

We will have to see once we get the AWD, 4R70W, trans under the truck.

hoosier1104 said:

If I am understanding everything correctly, VSS is a analog (sine) wave and my cluster is a digital (square) wave. So the convert needs to go inline on the cluster circuit either in front of PCM before the main harness connection or just after the connection. I also have a module to correct the actual speed as well.

Click to expand...

The 96 PCM is not involved at all in the conversion - it is a user of the final corrected VSS signal just like the speedometer.

To the best of my knowledge, using a sensor like the tranny OSS or axle ABS:

Low voltage raw VSS source ----> Correction module ----> 0~12v square wave to Speedo/Cruise/PCM in parallel

hoosier1104 said:

I also have a module to correct the actual speed as well.

Click to expand...

Are you sure that the module that you already have will not do the frequency correction AND the amplitude/waveform correction? I believe that some aftermarket speed boxes have that capability.

SpeedChanger

They are 2 separate pieces. I forget who the manufacturer is off the top of my head though. It was someone Pete recommended though. The converter I should have built myself since I have a electronics engineering degree and all. Oh well.

rwenzing said:

The 96 PCM is not involved at all in the conversion - it is a user of the final corrected VSS signal just like the speedometer.

To the best of my knowledge, using a sensor like the tranny OSS or axle ABS:

Low voltage raw VSS source ----> Correction module ----> 0~12v square wave to Speedo/Cruise/PCM in parallel

Are you sure that the module that you already have will not do the frequency correction AND the amplitude/waveform correction? I believe that some aftermarket speed boxes have that capability.

SpeedChanger

Click to expand...

That is exactly what I have.

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