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Help with Vehicle Speed Sensor

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  #1  
Old 02-06-2011, 08:57 PM
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Default Help with Vehicle Speed Sensor

I have a 1994 Accord Ex and the speedometer is not working. Based on what I have read it seems like the VSS is supposed to output a square wave voltage at the orange wire of 5V while spinning the front wheel by hand. I don't get any voltage at the orange wire comming from the VSS only a change in continuity. The plug however does have 5 volts on it at all times with the ignition on. Black is ground and the yellow is 12 volts. Is this correct?

Thanks

http://techauto.awardspace.com/vss.html
 
  #2  
Old 02-06-2011, 09:17 PM
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Do you have a ECU code 17 and/or TCU code 4? If either of these codes are present the VSS is not generating adequate signal, or you have wiring or connector fault.

Measuring VSS output should go from +5 to 0V between B10(+) and A26 (-) at the ECU harness connector. If you disconnected the VSS, you can't get this output.

good luck
 
  #3  
Old 02-06-2011, 09:34 PM
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Originally Posted by TexasHonda
Do you have a ECU code 17 and/or TCU code 4? If either of these codes are present the VSS is not generating adequate signal, or you have wiring or connector fault.

Measuring VSS output should go from +5 to 0V between B10(+) and A26 (-) at the ECU harness connector. If you disconnected the VSS, you can't get this output.

good luck
Ok, can you tell me where the ECU harness connector is located. Are B10 and A26 pins that are visable when the connector is disconnected. If so, do you happen to know where to find a pin diagram?

I have just started reading on this forum and I happen to notice that a group of people had the same problem that I did. Speedometer doesn't work, ABS light is on, clicking under the glovebox, radio goes occasionally and strange corrision on the battery. Could all of this be related?

Thanks so much for your help.
 
  #4  
Old 02-07-2011, 05:51 AM
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Unlikely that problems are related.

Download a 94-97 Accord manual from the Online Manuals links in diy forum. This has info on ECU harness location (under passenger side floor mats). You'll need to remove door rocker arm cover, kick panel trim and pull carpet back to expose ECU/TCU module. Release module holddowns and then you can disconnect ECU connections to perform test.

I re-read the 94 manual I have and found that a test harness is necessary to allow the ECU to be functional while you perform the test. So, it will be necessary to backprobe (again see manual) with connections in place to perform this test.

You could also backprobe the harness at the driver's side shock tower (wheel well area) to access these same wires. Again, the shop manual is essential.

Because of relative difficulty of performing these tests, most opt to replace the VSS, if the VSS code is presented.

Have you checked for VSS code? See DIY section for guidance on accessign the ECU codes.

good luck
 
  #5  
Old 02-07-2011, 06:04 PM
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Originally Posted by TexasHonda
Unlikely that problems are related.

Download a 94-97 Accord manual from the Online Manuals links in diy forum. This has info on ECU harness location (under passenger side floor mats). You'll need to remove door rocker arm cover, kick panel trim and pull carpet back to expose ECU/TCU module. Release module holddowns and then you can disconnect ECU connections to perform test.

I re-read the 94 manual I have and found that a test harness is necessary to allow the ECU to be functional while you perform the test. So, it will be necessary to backprobe (again see manual) with connections in place to perform this test.

You could also backprobe the harness at the driver's side shock tower (wheel well area) to access these same wires. Again, the shop manual is essential.

Because of relative difficulty of performing these tests, most opt to replace the VSS, if the VSS code is presented.

Have you checked for VSS code? See DIY section for guidance on accessign the ECU codes.

good luck
Yes I had a code 17. I replaced the VSS but the speedometer still does not work. However the light did go away.

Is it possible to have a code 17 and it be something beside the VSS?

Thanks
 
  #6  
Old 02-07-2011, 07:12 PM
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If the odometers (trip and cumulative) are working, then instrument panel has a fault. Easiest fix is to replace the panel w/ a used panel and file an amended mileage statement w/ state vehicle registration.

good luck
 
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