The Vehicle Speed Sensor (VSS) is located on the rear axle housing.
OPERATION The PSOM receives a vehicle speed signal from the Differential Speed Sensor (DSS) on pin 4 DSS input, and pin 5 DSS return. It converts this signal to a standard 8000 pulses-per-mile speed signal output. This output signal is sent to the PCM on pin 3 PSOM (+) and pin 6 PSOM (-).The PSOM receives two power supply inputs. Pin 1 receives a continuous 12.0 volt input while pin 2 receives a 12.0 volt input only when the ignition switch is in run.RELATED DIAGNOSTIC TROUBLE CODES DTC 29/452 PCM detected an error in the PSOM output signal.
I will opt out so another expert can help you.
OK, thanks for trying. I also get a 628 code KOEO. This started about two weeks ago and got to the point I can't drive it. This is the part when I search for VSS. Where does this go?
new expert. Looks like the VSS you have goes in line on the speedo cable. If you are having issues with the speedometer acting up the cable can fail/get dry and bind. I remember being able to grease the cables when they started bouncing, even had a tool to grease it without disconnecting it from the instrument cluster head.
The VSS could also be mounted in the rear of the transfer case.
they show 2 instrument cluster set ups, electronic and old style with cable.
let me know what you find
If the cluster speedo is electronic then the VSS is different and mounts in the transfer case. you will get the codes if the signal is lost. It could be the gear is slipping or is damaged. I am try to find a picture, hard with vehicles older than 10 years.
The code 452 is for the VSS, could be a harness/wire issue too.
should look like this
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I am sorry I have not been more available today. I needed to move my son. This is very helpful and I will try to find the sensor. This looks like the 92 model. I looked at this part at Autozone, but it looks like the round end above the elec plug is for a cable and I do not have a cable driven speedo. This truck has a plate on the door that it was manufactured in 92 and titled as a 93. When I search for the 92 VSS this is a choice. Any ideas as to the location on the transfer case? The only wiring I find is for the 4wd switch. I will look more tomorrow.