Speedometer won't Move, Ford Escort SE 1998 Wagon

Tiny
INDUSTRIFLOW
  • MEMBER
  • 1998 FORD ESCORT
  • 2.0L
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 95,000 MILES
My Escort wagon runs fine, but the speedometer and odometer never move. Speedo stays at zero. No fluctuation. Odo never changes. The rest of the instrument cluster works fine.

OBD II code P0500 (details below).

This car does not have cruise control, so it's not related to that.

Has automatic transmission. Drives fine. I've heard a bad VSS would cause the engine to hesitate. So I'm doubting the VSS itself needs replacement. I've also read the VSS can be very difficult to extract.

I've looked directly at the VSS (removed the battery and air box), and the wires to it look fine and intact. Not even brittle. I gently wiggled the wires--they're solid.

I removed and checked the connectors at the battery's negative terminal. The plastic connectors look fine; not brittle; still have a little bit of that clear gel that I assume Ford puts on them to keep the metal clean.

But I suspect a wiring problem.

I'm skilled with a volt-ohmmeter, DVM and ammeter. Can I probe for certain signals on certain wires to troubleshoot this?

Ford circuit diagrams, schematics, and WIRES' LOCATIONS would be great to have!

Autozone provided this OBD II code: P0500. "Vehicle speed sensor circuit condition."
"The ECM has detected a fault in the vehicle speed sensor circuit."
"Probable cause:"
"1. - Poor electrical connection or short circuit condition."
"2. - Failed vehicle speed sensor."
"3. - Drive gear mechanical fault."

What do you recommend?
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Friday, August 15th, 2014 AT 12:20 PM

7 Replies

Tiny
SATURNTECH9
  • EXPERT
The first thing I would do is unplug the speed sensor inspect the connector/harnesses side terminals make sure nether one looks open. Then measure the resistance across the speed sensor terminals with it unplugged from the harness. Let me know what you find?
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Friday, August 15th, 2014 AT 12:30 PM
Tiny
INDUSTRIFLOW
  • MEMBER
There are a few connectors atop the transmission. I worked on the only connector with two wires. Held on with one 10 mm bolt.

The connector/harnesses terminals look fine. The two wires do not look brittle or frayed. They feel solid in the connector.

Resistance across the two male prongs on the speed sensor is 399 Ohms while bolted on the trans. Measures 386 Ohms when removed.

I'm amazed how easy it was to remove. After removing the one bolt, I lifted out the sensor immediately--not even a twist required.

Turns out, there seem to be two types of speed sensors listed for Ford Escort 2.0L SPI engines (including for my 1998). One is longer, with a gear that sits down in the trans, and the electrical connector sticks straight upward. The other type (mine) is short, has a copper pulse sensor instead of a gear, and the electrical connector sticks out to the side--at a right angle (photo attached).

Autozone and other parts stores show only the longer sensor with the gear. But, some parts suppliers show the sensor without the gear, listed (for example, at TascaParts) as part # F32Z-7F040-A "Speed Pulse Generator." It's about 107 bucks, instead of 70 for the one with the gear. I'm tempted to pull one from the local salvage yard.
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Thursday, August 21st, 2014 AT 10:34 PM
Tiny
INDUSTRIFLOW
  • MEMBER
I think I made a mistake. That's the turbine shaft speed sensor--the photo in my previous post.

The photo below is looking down. Front of car is to the left. The turbine shaft speed sensor is the gray connector at the photo's bottom center.

Which is the VSS? Am I looking in the wrong place?
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Thursday, August 21st, 2014 AT 11:30 PM
Tiny
INDUSTRIFLOW
  • MEMBER
I found the VSS, behind the engine, 18 inches below the hood, roughly centered between driver & passenger. The connector's and harness' terminals look fine, and are not brittle or frayed, and feel solid in their connectors.

The resistance across the two male prongs on the VSS is 218 Ohms.
(while unplugged from the wiring harness)

What is that resistance supposed to be?
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Friday, August 22nd, 2014 AT 6:50 PM
Tiny
SATURNTECH9
  • EXPERT
Let me look that up for you.
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Saturday, August 23rd, 2014 AT 11:05 PM
Tiny
SATURNTECH9
  • EXPERT
Its supposed to be 190-250 ohms.
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Sunday, August 24th, 2014 AT 7:19 PM
Tiny
INDUSTRIFLOW
  • MEMBER
So, my VSS terminals' resistance is within the normal range. Does that mean definitively that the VSS itself is good?

Would this mean the problem is most likely an electrical short in the wiring between the VSS's connector and the instrument cluster?

Does Ford have particular troubleshooting steps for this?

Thanks for any assistance here!
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Monday, August 25th, 2014 AT 1:14 PM

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