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Hello everyone,
I have a 1996 Ford bronco Eddie Bauer, it has sat for about 4 years unfortunately but all is good getting her back on the road! After I got my break issues taken care of I took it down the road and truck went into limp mode and threw a vss code. I replaced the sensor and still not fixed. I read that vss goes through abs computer then to pcm then to the cluster so before I start buying computers I want a little info. I checked for voltage at sensor and I get anywhere from 1.5-2.5 volts was curious if anyone knows exactly what voltage I should expect. Fuses are good so if voltage is normal then I know to attack computer or wiring harness
The VSS will not generate any voltage until the vehicle is moving. The tone ring is attached to the ring gear in the rear axle. The movement of the tone ring triggers the VSS to start generating a square wave output.It's a varying frequency and voltage. The voltage should increase from 0 to ~3.5 VAC at 30 MPH.
Is the odometer on with the key in the On position?
If yes to the above does it increment as you drive down the road?
Is the speedometer registering any speed or bouncing?
Your theory on how the VSS circuit works is a bit flawed: I read that vss goes through abs computer then to pcm then to the cluster
You are correct the VSS goes through the ABS controller then it goes to the PSOM located behind the instrument cluster. The PSOM converts the raw VSS signal to something usable for the computer (PCM) and the speed control servo/amplifier.
When I say I want to know voltage I'm referring the the male connector that plugs into the vss itself not the sensor, but to answer your question no speedo movement what so ever and also the tach will not count miles
There should not be any voltage at the male plug that I am aware of. From a VSS operation perspective the output is AC so if you had the DVM set to DC volts there may be a DC component from the 4WABS module.
You can test the VSS output with a DVM set to AC. Ensure the truck is set to 2WD mode, block the front tires, jack up and secure the rear axle then run the truck up to ~30 MPH (or guess) the output should increase from 0 to ~3.5 VAC. If that is good then move on to the output of the 4WABS module.Seems to me that is a common area that screws up the signal. Could be corroded connectors.
If you do not like the idea of having a running vehicle with wheels spinning start with ohming out the wires using the diagram above.
Well I put In a new sensor so it should be good but I will test just to double check, but since you say that I have an idea what the problem might be. Someone cut every wire going into the abs computer and spliced with crimp connectors probably just a bad connection but what do you think about a bad ground?
Someone cut every wire going into the abs computer and spliced with crimp connectors probably just a bad connection but what do you think about a bad ground?
The VSS signal is not grounded. Once it is buffered by the 4WABS module there is a ground reference.Butchered wiring is a bad sign of other easter eggs hidden by previous owners.
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