Where is the speed sensor located?

Tiny
JOE BISCANTI
  • MEMBER
  • 1998 CHEVROLET PRIZM
  • 177,777 MILES
Car parts store put a scan tool on my car, showed speed sensor. The speedometer and odometer disappear from view and then show up again. It is doing this more often and the problem lasts longer. The car listed above has a 5-speed manual transmission. Where is this speed sensor located? I cannot find it looking under the hood.
Saturday, April 2nd, 2022 AT 6:18 AM

36 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Hi,

It should be on the driver's side, mounted on the top of the transmission closest to the firewall.

Take a look at the pic below and let me know if you find it. If you do, the remaining pictures are the directions for replacing it.

Let me know if this helps.

Joe

See pics below.
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Saturday, April 2nd, 2022 AT 9:47 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
Following your diagram, I looked down and I think I may have found it. Does the top radiator hose go over the top of its location? I see wires and a plug, but I don't see a bolt. I see an Allen head bolt next to it but it doesn't appear to be connected to what I'm seeing. I also see a ground wire near it. What I'm looking at is under the air cleaner box. Thanks for your help, as you can tell I'm no mechanic. It looks like I could replace it, if I found it. Respectfully submitted Joe Biscanti.
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Sunday, April 3rd, 2022 AT 7:27 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Hi,

It is likely under the air induction tube or the air filter box. It will have a three-wire connector. Is that what you are seeing? If it is, that is the likely part.

Let me know. Also, if you are questioning if you are correct, take a pic of it and upload it for me to see.

Let me know.

Take care,

Joe
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Sunday, April 3rd, 2022 AT 4:11 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
Hello, I don't know how to take and upload pictures. A friend told me to get a can of BrakLeen to clean up the built-up grime so I can see it better. The wire that connects to what I'm seeing looks like the wire connection in your diagrams, appears to be 3-wire. As soon as I get a chance I will clean and recheck. It is under the air cleaner box, not directly under but close. I really appreciate your help. I will let you know what I see when I get it cleaned up. Respectfully submitted, Joe Biscanti.
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Monday, April 4th, 2022 AT 7:29 AM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
Hello, I went to the car parts store and got some CRC electronic parts cleaner. It cleaned up the area very good. What I'm looking at has two wires going in the top (no bolt found). It looks more like a sensor or sending unit that if you unplugged it, it could be removed with the correct size socket. It is in the location on your diagram. Respectfully submitted, Joe Biscanti.
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Monday, April 4th, 2022 AT 8:51 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Hi,

The VSS should be bolted in place. Take a look at the attached picture. That is what you should be looking for.

Let me know.

Joe
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Monday, April 4th, 2022 AT 2:08 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
It doesn't look like that. It looks like a two-wire sending unit, that if you disconnected the wires, you could get a socket on it. I sprayed it with CRC electronic cleaner, and it started working again. Then I put some dielectric grease on the connections, and it stopped working. I sprayed it really good, and I think I got rid of the grease. I will let it sit overnight and see what happens. Maybe that spray cleaning was just a fluke. In any case it doesn't look like the picture you sent me. I will look around again (weather permitting tomorrow). I really do appreciate your help and patience. Maybe I need to take off the air cleaner box to get a better look. Respectfully submitted, Joe Biscanti.
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Monday, April 4th, 2022 AT 3:29 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Joe,

What you are describing doesn't sound correct. It sounds more like a temperature sensor or even a pressure sensor. Could you get a pic of it and upload it for me to see?

Let me know.

Joe
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Monday, April 4th, 2022 AT 6:44 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
I'm sorry but I don't know how to do that. It does have two wires going into the top through two blue plastic (?) Deals. This is threaded into the top of the transmission. The wires go into a wiring harness going to the under the hood fuse box. Below the air box appears to be a transmission mount. I don't see anything like your picture anywhere near this area. The scan report says no solution found. Additional diagnostic work is needed to determine the issue. Locate a repair shop near you. Diagnostic trouble codes - power train system. Secondary DTCs- P0500 Vehicle speed sensor A. I don't know if this helps. Thanks again for your patience and help. Respectfully submitted, Joe Biscanti.
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Tuesday, April 5th, 2022 AT 7:02 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Hi,

There are two transmissions used on this model, but both take the same sensor.

Let's try this a different way. I attached the wiring colors from the sensor. See if you can locate those three colors going to the same sensor.

Let me know what you find or if you have questions. Also, if possible, take a picture of what you are seeing.

Let me know.

Joe

See pic below.
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Tuesday, April 5th, 2022 AT 5:42 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
Thanks so much for your help and patience. I only see two wires going into the top. I don't see anything like the picture you sent me. I made an appointment with the garage to have it checked out. Respectfully submitted, Joe Biscanti
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Wednesday, April 6th, 2022 AT 6:46 AM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
Cancel that last reply please. I found the speed sensor. It was right near the fire wall where you said it was. I can access the bolt. I loosened it and retightened it. I 'm not sure how to unplug the speed sensor electrical connector which I need to do to pull the speed sensor out. I will wait for your reply before I order a speed sensor from Rock Auto. Never give up. Respectfully submitted, Joe Biscanti
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Wednesday, April 6th, 2022 AT 8:51 AM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
Attn: Joe F. Expert. I was reading your installation procedures, what is J 36850 lubricant or equivalent? I ordered a speed sensor today from Rock Auto. Walker products 2401037 speed sensor. 1998 Chevy Prism 1.8 liter 5 speed manual transmission. Looking forward to your reply. Respectfully submitted, Joe Biscanti
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Wednesday, April 6th, 2022 AT 3:56 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Hi,

That is what is typically called assembly lubricant. The directions most likely indicate to lubricate the o-ring on the part and where it attaches. You can use the gear oil for the transmission or even engine oil. I've even used Vaseline. LOL, the goal is to prevent damage to the rubber component during installation.

I hope this helps. Let me know how things turn out for you.

Joe
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Wednesday, April 6th, 2022 AT 5:16 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
Great advice, thank you. I'm not sure how to unplug the speed sensor electrical connector. I don't want to break it. I could use some instructions on how to unplug it without damaging it. Thanks in advance for your help. Respectfully submitted, Joe Biscanti
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Wednesday, April 6th, 2022 AT 9:21 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Joe,

By chance, could you upload a pic of what you have? There are so many different types that have been used.

If I had to guess, there will be a release on the one side that you press with your thumb to release it. I attached a pic below and highlighted the release on the pic. See if that is what you have.

Let me know.

Joe

See pic below.
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Thursday, April 7th, 2022 AT 12:45 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
I don't know how to upload and send pictures. I'm 71 years old and not too computer savvy. My eyes aren't so good either. I think that might be what it looks like. I'll have to use a magnifying glass to see it better. I will check it whenever it stops raining here. Rock Auto says the sensor might get here on or after 12 APR 2022. I will let you know about the connector. Thanks so much for your help. Respectfully submitted, Joe Biscanti
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Thursday, April 7th, 2022 AT 11:13 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Joe, I'm not too far behind. I'm over 50. LOL Let me know if there is anything I can do to help.

Take care of yourself,

Joe
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Friday, April 8th, 2022 AT 5:43 PM
Tiny
JOE BISCANTI
  • MEMBER
  • 21 POSTS
The garage gave me an estimate of between $400.00 to $500.00 to do this job. I have the sensor being shipped from Rock Auto for $96.00. So, it's worth taking a shot. I will let you know when I receive the sensor and how the attempted installation goes. With your information I think I could do it. Respectfully submitted, Joe Biscanti
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Saturday, April 9th, 2022 AT 6:22 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,108 POSTS
Wow, the book allows.5 hour (30 minutes) for labor. Either they have a crazy expensive labor rate, or they are confused about what needs to be done. If you were supplying the part, it would cost you under $50.00 labor for us to install it. LOL

Regardless, certainly, you can do it. It is disconnecting a connector, removing a bolt, and removing the sensor. If you run into any trouble trying to remove the sensor, let me know. Be careful and don't force it. It can break. Maybe an hour or so before you plan to work on it, spray where the sensor enters the transmission and the bolt itself with a penetrating fluid, so it comes apart easier. Once the bolt is removed, gently wiggle and turn it back and forth to loosen it.

Take care and let me know if I can help in any way.

Joe
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Saturday, April 9th, 2022 AT 8:26 PM

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