Fluttering speedometer/vehicle speed sensor problems.

masanders · Aug 12, 2017

I'm not sure if this should be posted here or in gauges (it involves both the vss and gauges). Moderator, please move this if necessary.

Just tried to swap in a gauge cluster with tach into a 2000 Ranger XLT 2.5 MT 4x2. Both older and newer speedometers were rising to about 35mph and then the needle would flutter. I read that the resistance for the VSS should top out at 1.4. My VSS topped out at 1.98. It was also cracked badly.

According to the write up in one of the tech sections the sensor is bad because of the reading.

Would swapping the clusters have killed the VSS (was working fine before swap)?

2000 Ranger XLT 2.5 4x2 MT

RonD · Aug 12, 2017

Not sure you can test a VSS with OHM meter to see if it is OK, you can test to see if it is bad but that doesn't make it OK
Kind of like testing an ignition coil.

Ford uses a 2 wire Variable Reluctance VSS, this is an UNpowered sensor, just a coil of wire around a metal core.
There is Tone wheel with metal teeth that passes by the VSS when vehicle is moving, each time a tooth passes by, it causes magnetic field to expand and collapses, this generates an AC Voltage in the VSS
This AC Voltage is a sine wave, you can measure this AC Voltage with volt meter set to AC Volts, .3 to 1.5volts AC depending on tone wheel speed.
BUT..........speed isn't determined by the AC Voltage directly, the Sine Wave peaks and valleys are used, just the peaks, the valleys are Grounded out.
This creates the PPM(Pulse Per Mile) used by speedo and computer

High OHMS would show disconnected wire in coil of VSS, 0 ohms would show short inside VSS, in between is pretty much a working VSS as far as OHM testing is concerned.
140–250 ohms would be more in line if using lowest scale on ohm meter, so 1.4 to 2.5 if using higher scale

If speedometer hasn't been tested by you before then I would say problem is there, not VSS, can't see anyway you could hurt VSS by swapping clusters out.

In 2000 the rear axle VSS signal(PPM) goes to the GEM(generic electrical module) behind the radio, GEM converts the rear axles 12,000+PPM down to the 8,000PPM the computer and speedometer expect, so GEM is part of the system.

But if GEM or VSS was faulty then computer would turn on CEL and have P0500 code, VSS signal problem.

masanders · Aug 13, 2017

RonD said:
High OHMS would show disconnected wire in coil of VSS, 0 ohms would show short inside VSS, in between is pretty much a working VSS as far as OHM testing is concerned.
140–250 ohms would be more in line if using lowest scale on ohm meter, so 1.4 to 2.5 if using higher scale

I'm not really sure about the testing, but I'm going off a sticky that Jim Oaks put up and a write up by aa1car.com. Both gave the same range values although under different OHM settings, 800-1400 OHMS or .8-1.4 OHMS.

Here's the timeline of what I did:

1. Took out non tach cluster (speedometer was working at this time)
2. Installed new speedometer with tach (no calibration...don't know how yet)
3. New speedometer fluttered
4. Swapped speedometer motor(?) to old one.
5. Speedometer fluttered
6. Took out new cluster
7. Reinstalled old cluster
8. Speedometer still flutters on original cluster that wasn't fluttering before removal.

I haven't tested or inspected the harness yet, but it's on my to do list.

It just seems to me that if both clusters are showing the same symptoms, then the problem is somewhere else. They're just indicators.

2000 Ranger XLT 2.5 4x2 MT

RonD · Aug 13, 2017

Check that the cluster Ground wires are still connected

VSS has one wire that is the Ground, a reference, so only the peaks of the sine wave are used, but without a stable reference then there are no stable peaks

On 2000 Ranger instrument cluster C215 connector pin 1 gray/black wire is VSS signal from GEM(pin 1),(this wire is spliced and goes to PCM pin 58 as well)
Pin 2 on C215 connector is the Ground, black/wire wire, for speedo, but same ground is shared by other gauges.

Yes I would agree that if old cluster wasn't fluttering, and new cluster did, and now old cluster is also fluttering then problem would go back to gray/black wire or ground, then to GEM and then to VSS itself.
But still can't see damaging a coil of wire(VSS) via instrument cluster swap
Maybe hit a wrecking yard and get one, a VSS

masanders · Aug 14, 2017

Installed a new VSS and the speedometer works again, but is mildly shaky during acceleration and constant speed. I'm not sure what I'm supposed to be testing for with the ground wire (resistance, continuity, signal). I checked for continuity and my multimeter produced a tone. I cleaned the contacts on the circuit board just in case.

Is this just because it is a manual?

I don't know much about the GEM but I do know that other things that TRS members have posted about what the GEM controlling work.

2000 Ranger XLT 2.5 MT 4x2

masanders · Aug 14, 2017

It probably shouldn't matter but the newer cluster came out of a 2000 Ranger 4.0 AT while mine is a 2000 Ranger 2.5 MT

2000 Ranger XLT 2.5 MT 4x2

RonD · Aug 14, 2017

Yes, continuity, 0 OHMs, between Ground wire and cab metal(ground)

No, shouldn't matter for the year, and Tach signal comes from the computer so no 4, 6, or 8 cylinder adjustment is needed

Speedo is electric, and much more sensitive than dash volt meter, put your volt meter on the battery terminals with engine running, rev the engine a few times and watch meter, also slowly increase RPMs to above 2,500 and watch meter.
You are looking for unsteady voltage.
Also going down a hill and/or coasting watch speedo needle and turn on headlights and blower fan to high, see if either effects the needle

masanders · Aug 14, 2017

RonD,

I took my Ranger for a quick drive to see if the problem was still happening. The needle no longer shakes, but the speedometer is reading about 5mph high. I saw a YouTube video where the guy attached a 1.5v battery to the posts around the back of the speedometer motor. The voltage produced a reading of 73mph. He suggested that if you have to take the needle off to do the same voltage calibration and put the speedometer needle back on at 73mph.

Is this a valid test or calibration procedure? Is 73mph the value to go off of?

Thanks for the help.

2000 Ranger XLT 2.5 MT 4x2

RonD · Aug 14, 2017

Never did that, but the voltage would have to be very stable, if you are basing 1.5v = 73MPH
Have no idea if that is a valid calibration

And 5MPH high at what speed?
If you try the test then your speedo should show 78+MPH with 1.5v, if so then reset to 73 and give it a try
And measure voltage on battery if thats what you are using, if it is 1.6v or 1.4v ????

The GEM in 1998-2000 Rangers is used to calibrate signal to the 8,000PPM the speedo is setup for, so changing the dash shouldn't have effected calibration.
Since it is using rear axle sensor only the tire size is a variable and thats what is programmed into the GEM, stock tire size.

Taller tires should cause lower speed reading, shorter tires higher speed

masanders · Aug 18, 2017

Doing testing on the ground wire at C215 and it says it has continuity but the resistance on 200 setting = 3.5

2000 Ranger XLT 2.5 4x2 MT

masanders · Aug 18, 2017

Resistance between GEM connector and C215 pin 2 = 00.0

2000 Ranger XLT 2.5 4x2 MT

masanders · Aug 18, 2017

RonD,

Color me confused...

I'm not good at taking electrical readings, but it seems like I may have read something wrong. I say that because after calibrating the speedo (which wasn't all that hard after all) everything hooked up and worked flawlessly.

I'm going to chalk that up to a win and leave it alone! Only one 194 bulb seems to be out but it's only lighting up the 90-120mph area. Don't really think I'll be going that fast...at least without a flux capacitor.

Thanks for all the help RonD! You have been immensely helpful and a valuable resource in getting my late father's truck back on the road!

2000 Ranger XLT 2.5 4x2 MT

RonD · Aug 19, 2017

Good work

red2003xlt · Feb 20, 2019

I hate to revive an old thread

I've got the same issue.

2003 XLT 3.0 I'm the original owner BTW.

My ranger did before result in temporary total lack of power and every warning light on the dashboard lit.

I turned it off and back on and everything working except the AC/heater.

Also the 5r55 started to buck and would actually "let go" under hard acceleration.

Any ideas? If I need a separate thread let me know.

83,000 miles.

Fluttering speedometer/vehicle speed sensor problems.

Active Member

Official TRS AI

Active Member

Official TRS AI

Active Member

Active Member

Official TRS AI

Active Member

Official TRS AI

Active Member

Active Member

Active Member

Official TRS AI

Member

Sponsored Ad

Sponsored Ad

Member & Vendor Upgrades

Truck of The Month

Recently Featured

Follow TRS On Instagram

TRS Events

25th Anniversary Sponsors

Check Out The TRS Store

Sponsored Ad

Sponsored Ad

Sponsored Ad

Amazon Deals