Speedometer needle bouncing all over the place.
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
Speedometer needle bouncing all over the place.
This problem has continued to get worse. It started with the needle dropping to 0 mph when I would get below 30 mph, and it wouldn't register until I got above 30 mph, but once above 30 mph it would read correctly. Now it is just bouncing all over trying to find the correct speed.
My after market NAV system displays the correct MPH, so I know that it is picking up the signal from the VSS wire coming out of the PCM.
I have replaced the VSS sensor in the differential already and it did not help.
Does anybody know if there is a stepper motor in the analog gauge cluster? The needle is bouncing around like the old style mechanical speedos when they would start going bad.
My after market NAV system displays the correct MPH, so I know that it is picking up the signal from the VSS wire coming out of the PCM.
I have replaced the VSS sensor in the differential already and it did not help.
Does anybody know if there is a stepper motor in the analog gauge cluster? The needle is bouncing around like the old style mechanical speedos when they would start going bad.
Burning Brakes
Joined: Nov 2007
Posts: 951
Likes: 2
From: Rochester MN
I'd begin by reading out the diagnostic trouble codes (DTC) from your instrument cluster.
Here is a link as how to do that.. You may find your problem from the codes...
http://forums.corvetteforum.com/c5-t...-problems.html
Here is a link as how to do that.. You may find your problem from the codes...
http://forums.corvetteforum.com/c5-t...-problems.html
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
I'd begin by reading out the diagnostic trouble codes (DTC) from your instrument cluster.
Here is a link as how to do that.. You may find your problem from the codes...
http://forums.corvetteforum.com/c5-t...-problems.html
Here is a link as how to do that.. You may find your problem from the codes...
http://forums.corvetteforum.com/c5-t...-problems.html
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Recommend removing the entire cluster and do a disassemble ad inspect. You may fins a poor connection or a cold solder joint. Heres a post that may help you:
- C5 Gage Cluster disassembly - http://forums.corvetteforum.com/c5-t...post1570380674
If a simple tear down and reassembly doesn't fix it,, you will need a new one..
- C5 Gage Cluster disassembly - http://forums.corvetteforum.com/c5-t...post1570380674
If a simple tear down and reassembly doesn't fix it,, you will need a new one..
Last edited by Bill Curlee; Dec 10, 2011 at 06:28 PM.
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
Recommend removing the entire cluster and do a disassemble ad inspect. You may fins a poor connection or a cold solder joint. Heres a post that may help you:
- C5 Gage Cluster disassembly - http://forums.corvetteforum.com/c5-t...post1570380674
If a simple tear down and reassembly doesn't fix it,, you will need a new one..
- C5 Gage Cluster disassembly - http://forums.corvetteforum.com/c5-t...post1570380674
If a simple tear down and reassembly doesn't fix it,, you will need a new one..
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
Recommend removing the entire cluster and do a disassemble ad inspect. You may fins a poor connection or a cold solder joint. Heres a post that may help you:
- C5 Gage Cluster disassembly - http://forums.corvetteforum.com/c5-t...post1570380674
If a simple tear down and reassembly doesn't fix it,, you will need a new one..
- C5 Gage Cluster disassembly - http://forums.corvetteforum.com/c5-t...post1570380674
If a simple tear down and reassembly doesn't fix it,, you will need a new one..
How can I tap into the VSS and not affect the signal to the Speedo?
Thanks
Tech Contributor
Joined: Jan 2007
Posts: 19,342
Likes: 1,123
From: Dyer, IN
Update. I removed the wire from my NAV unit that was tapping into the VSS wire at the PCM connector. Now my Speedo works fine. I don't know if the wire that was tapping into the PCM was picking up the signal between the VSS and PCM connector, or if it was the wire between the PCM and the Speedo?
How can I tap into the VSS and not affect the signal to the Speedo?
Thanks
How can I tap into the VSS and not affect the signal to the Speedo?
Thanks
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Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
Not in this case, I have had this unit for about 5-6 years now. The particular NAV that I have needs a VSS connection. It is a JVC model. I have hadd it hooked up and it works great and displays the correct mph on the NAV, but it effects the signal under 30 mph on the speedo...and one time it didn't matter what mph I was going the speedo needle was bouncing.
Tech Contributor
Joined: Jan 2007
Posts: 19,342
Likes: 1,123
From: Dyer, IN
Not in this case, I have had this unit for about 5-6 years now. The particular NAV that I have needs a VSS connection. It is a JVC model. I have hadd it hooked up and it works great and displays the correct mph on the NAV, but it effects the signal under 30 mph on the speedo...and one time it didn't matter what mph I was going the speedo needle was bouncing.
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
I would have to read the owners manual/wiring diagram to believe it. NAV units calculate speed based on position(from SATs), not from a VSS sensor. Not all VSS sensors are the same(with regard to ouput) from vehicle to vehicle.......so the unit would have to be capable of adapting to ANY VSS from any vehicle manufacturer. What is the model? Also, are you saying with the VSS input disconnected, the NAV does not display MPH, or the NAV does not function?
It is the NX5000 and the user manual clearly states to hook up to the vehicle's speed signal. I can't attach the PDF Install Manual. But if you go to JVC USA under Archive Car AV and search NX5000, download the Install PDF and go to table C and you can see it for yourself.
http://support.jvc.com/consumer/prod...1&archive=true
Last edited by Shinobi'sZ; Dec 28, 2011 at 02:17 PM.
Tech Contributor
Joined: Jan 2007
Posts: 19,342
Likes: 1,123
From: Dyer, IN
The NAV neither functions nor does it read the MPH because the VSS is not hooked up per the owners manual. When I turn the NAV on it is stuck at the the place it was working last..which is my garage where I disconeected the wire from it that I had connected to the VSS at the PCM conector.
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
I had it hooked up the VSS wire at the PCM, I didn't want the audio shop digging around in my PCM, so I told them that I would install it after they told be it needed to be hooked up to the vehicle's speed sensor, what I see in this install manual is to hook up the vehicle's speedometer signal.....
The VSS feeds the PCM and then the PCM sends a signal to the analog Speedo right? Maybe it needs to be hooked up to that wire and not the VSS wire coming from the sensor to the PCM.
Do you know which wire goes from the PCM to the Speedo?
Thanks for getting me to read the manual...I just took it from the Audio place that it needed to be hooked up to the Vehicle's Speed Sensor..which to me was the VSS.
The VSS feeds the PCM and then the PCM sends a signal to the analog Speedo right? Maybe it needs to be hooked up to that wire and not the VSS wire coming from the sensor to the PCM.
Do you know which wire goes from the PCM to the Speedo?
Thanks for getting me to read the manual...I just took it from the Audio place that it needed to be hooked up to the Vehicle's Speed Sensor..which to me was the VSS.
Tech Contributor
Joined: Jan 2007
Posts: 19,342
Likes: 1,123
From: Dyer, IN
I had it hooked up the VSS wire at the PCM, I didn't want the audio shop digging around in my PCM, so I told them that I would install it after they told be it needed to be hooked up to the vehicle's speed sensor, what I see in this install manual is to hook up the vehicle's speedometer signal.....
The VSS feeds the PCM and then the PCM sends a signal to the analog Speedo right? Maybe it needs to be hooked up to that wire and not the VSS wire coming from the sensor to the PCM.
Do you know which wire goes from the PCM to the Speedo?
Thanks for getting me to read the manual...I just took it from the Audio place that it needed to be hooked up to the Vehicle's Speed Sensor..which to me was the VSS.
The VSS feeds the PCM and then the PCM sends a signal to the analog Speedo right? Maybe it needs to be hooked up to that wire and not the VSS wire coming from the sensor to the PCM.
Do you know which wire goes from the PCM to the Speedo?
Thanks for getting me to read the manual...I just took it from the Audio place that it needed to be hooked up to the Vehicle's Speed Sensor..which to me was the VSS.
Let's start here. What wire (color and pin position) at the PCM connector was the NAV VSS wire spliced into?
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
Tech Contributor
Joined: Jan 2007
Posts: 19,342
Likes: 1,123
From: Dyer, IN
1) VSS input to the PCM, yellow wire, pin 21
2) VSS output from PCM to IPC, dark green/white stripe wire, pin 50
My guess is, you had it tapped into the dark green/white stripe wire. For whatever reason, the speedo does not like it. I would be more inclined to tap into the VSS input TO the PCM (yellow wire). In any case, I cannot help further, if you cannot provide exact info.
FWIW, I did some reading on the JVC NAV units. One of the biggest complaints, was the NAV was rendered nonfunctional without a VSS signal.
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
The connector pin locations do not go up to 255. There is one input, and one output for VSS on PCM connector C2:
1) VSS input to the PCM, yellow wire, pin 21
2) VSS output from PCM to IPC, dark green/white stripe wire, pin 50
My guess is, you had it tapped into the dark green/white stripe wire. For whatever reason, the speedo does not like it. I would be more inclined to tap into the VSS input TO the PCM (yellow wire). In any case, I cannot help further, if you cannot provide exact info.
FWIW, I did some reading on the JVC NAV units. One of the biggest complaints, was the NAV was rendered nonfunctional without a VSS signal.
1) VSS input to the PCM, yellow wire, pin 21
2) VSS output from PCM to IPC, dark green/white stripe wire, pin 50
My guess is, you had it tapped into the dark green/white stripe wire. For whatever reason, the speedo does not like it. I would be more inclined to tap into the VSS input TO the PCM (yellow wire). In any case, I cannot help further, if you cannot provide exact info.
FWIW, I did some reading on the JVC NAV units. One of the biggest complaints, was the NAV was rendered nonfunctional without a VSS signal.
Let's assume that the signal noise was interfering with the input to the PCM and thus why the speedo would only work above 30 mph...except for that one time the speedo needle was bouncing all over the place no matter the mph, I couldn't reproduce that error again, it went back to falling off at under 30 mph and not registering until above 30 mph.
Is the dark green/white stripe wire going into the connector at the back of the Speedo (DIC)? If so I would rather try and hook it up there.
Also are you referencing teh PCM Connector and wiring for a 2001. I think they were changed at some point in the model years (?).
Thanks for ID'ing the pinouts and wire colors.
Tech Contributor
Joined: Jan 2007
Posts: 19,342
Likes: 1,123
From: Dyer, IN
Actually you jogged my memory it was the yellow wire that I had it tapped into.
Let's assume that the signal noise was interfering with the input to the PCM and thus why the speedo would only work above 30 mph...except for that one time the speedo needle was bouncing all over the place no matter the mph, I couldn't reproduce that error again, it went back to falling off at under 30 mph and not registering until above 30 mph.
Let's assume that the signal noise was interfering with the input to the PCM and thus why the speedo would only work above 30 mph...except for that one time the speedo needle was bouncing all over the place no matter the mph, I couldn't reproduce that error again, it went back to falling off at under 30 mph and not registering until above 30 mph.
http://forums.corvetteforum.com/c5-t...m-pin-out.html
Thread Starter
Le Mans Master
Joined: Sep 2000
Posts: 6,976
Likes: 527
From: Clouds Over California
Not sure what the PCM does to the signal, before sending it to the IPC.
Yes, but this would be unnecessary work, considering you already have a wire run to the PCM...so you would only need tap into the Green/white wire there.
Yes, but you should not take my word for it.
http://forums.corvetteforum.com/c5-t...m-pin-out.html
Yes, but this would be unnecessary work, considering you already have a wire run to the PCM...so you would only need tap into the Green/white wire there.
Yes, but you should not take my word for it.
http://forums.corvetteforum.com/c5-t...m-pin-out.html
I will fiddle around with it again and see if I can get it to work, otherwise I either will have to deal with it, by the JVC Pulse Generator, or get a new NAV unit that doesn't need a VSS to work...most likely in this order. lol
