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-   -   Speedo and Odometer not working (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/speedo-odometer-not-working-274051/)

Azaka 02-20-04 05:20 PM

Speedo and Odometer not working
 
I seached and no one seemed to have the problem I'm having and I couldn't find anything that I think could help me.

After putting the dash back together after taking it apart to find out what was causing my high idle my speedometer and odometer don't move. The numbers on the odometer are there but they aren't increasing. My PFC also read 0 speed all the time.

What could be causing these to not function?

DjRannyKan 02-20-04 05:26 PM

check all the wiring in the dash, mabey it is grounded some where. I dont know where the pfc gets its speed readings at but mabey (prolly not), the wheel speed sencers are bad. If u have a scan tool u can hook it up and see if the wheel speed sencors are good.

Sorry about spelling.

jimlab 02-20-04 06:41 PM

The ABS sensors at the wheels feed the ABS computer only, they aren't used to drive the speedometer or the odometer.

The VSS (vehicle speed sender) is located in the tailshaft of the transmission and connects directly to the dash wiring harness beneath the dash (behind the A/C section) at connector X-14 (if you have a shop manual). The green and orange wires are the signal wires for the speedometer and odometer.

If you do not have either one working, check the four plugs on the back of the gauge cluster. They are difficult to snap into place with the hood in place and the steering column in the way, so it's entirely possible that one is loose.

machinis 02-25-04 10:24 AM


Originally posted by jimlab
The ABS sensors at the wheels feed the ABS computer only, they aren't used to drive the speedometer or the odometer.

The VSS (vehicle speed sender) is located in the tailshaft of the transmission and connects directly to the dash wiring harness beneath the dash (behind the A/C section) at connector X-14 (if you have a shop manual). The green and orange wires are the signal wires for the speedometer and odometer.

Which one of these wires goes to the ECU/Cruise Control? Is it the same signal from the VSS to the speedometer and ECU?

I am trying to get a speed signal for an AVC-R, but the ECU one is out of whack(as shown on the AVC-R readings), and so is my cruise control(it won't engage and somethings throws a check engine when turned on). My speedometer works perfectly.

jimlab 02-25-04 12:13 PM


Originally posted by machinis
Which one of these wires goes to the ECU/Cruise Control? Is it the same signal from the VSS to the speedometer and ECU?

I am trying to get a speed signal for an AVC-R, but the ECU one is out of whack(as shown on the AVC-R readings), and so is my cruise control(it won't engage and somethings throws a check engine when turned on). My speedometer works perfectly.

The AVC-R documentation has a diagram showing which wire is required... Page 19, diagram Z3-b.

http://www.apexi-usa.com/productdocu...savcr_wire.pdf

machinis 02-25-04 12:24 PM


Originally posted by jimlab
The AVC-R documentation has a diagram showing which wire is required... Page 19, diagram Z3-b.

http://www.apexi-usa.com/productdocu...savcr_wire.pdf

I've already seen this page a few times. I tapped the correct cable(second and third checked it). Here are the sysmptoms:
-AVC-R readings jump around +-40Km/H on any gear, except on 4th gear below 60Km/H, which is perfect when compared to the speedometer.
-Speedometer works perfectly.
-Cruise control stopped working about 3 months ago. If I try to use the cruise control in 4th gear below 60Km/H, it will work flawlessly; any other gear or faster than 60Km/H in 4th gear will not work and sometime will light up the check engine.

My question is, does the ECU gets the same signal as the speedometer?

jimlab 02-25-04 01:25 PM


Originally posted by machinis
My question is, does the ECU gets the same signal as the speedometer?
Good question, but I'll have to dig out my wiring manual to find out. :D

jimlab 02-26-04 01:07 AM

The ECU and the cruise control module both get their speed signal from the speedometer section of the gauge cluster.

The VSS (vehicle speed sensor) on the tailshaft of the transmission has two wires, green (G) and orange (O), which connect to the dash harness at plug X-14, which is under the dash, roughly behind the A/C. From there, the green wire becomes yellow with a red stripe (Y/R) and the orange wire becomes yellow with a white stripe (Y/W), through plug X-15, which is at the driver's end of the dash.

The Y/R and Y/W wires connect to the gauge cluster through terminals 3C and 3A on the third of four plugs on the back of the gauge cluster. These are the wires which drive the odometer and speedometer.

From the gauge cluster, terminal 3E (same plug) is a green wire with a red stripe (G/R), right next and on the same row as 3C and 3A. This is the speed output wire to the cruise control and ECU. (schematic C-1a, page Z-42 in the wiring manual)

The G/R wire goes back out to plug X-15 (driver's end of the dash) into the dash harness. From there it goes two directions. The first is plug X-07, which is on the passenger's side of the dash, not far from X-14. The engine harness plugs into this plug, and the G/R wire travels through that harness, makes a loop and down to the ECU, where it enters the ECU at terminal 1M. (schematic B-1d, page Z-34 in the wiring manual)

Terminal 1M corresponds to the "speed" terminal in the AVC-R wiring in schematic Z3-b. You should have connected to a green wire with a red stripe. If you didn't, that's your problem.

The G/R wire also connects to the cruise control module behind the driver's side kick panel, at plug Q-01, terminal E. (schematic Q, page Z-108 in the wiring manual)

machinis 02-26-04 01:46 PM

http://carrito.net/forums/html/emoticons/respect.gif
Thanks a lot!!

Originally posted by jimlab
The ECU and the cruise control module both get their speed signal from the speedometer section of the gauge cluster.

The VSS (vehicle speed sensor) on the tailshaft of the transmission has two wires, green (G) and orange (O), which connect to the dash harness at plug X-14, which is under the dash, roughly behind the A/C. From there, the green wire becomes yellow with a red stripe (Y/R) and the orange wire becomes yellow with a white stripe (Y/W), through plug X-15, which is at the driver's end of the dash.

The Y/R and Y/W wires connect to the gauge cluster through terminals 3C and 3A on the third of four plugs on the back of the gauge cluster. These are the wires which drive the odometer and speedometer.

From the gauge cluster, terminal 3E (same plug) is a green wire with a red stripe (G/R), right next and on the same row as 3C and 3A. This is the speed output wire to the cruise control and ECU. (schematic C-1a, page Z-42 in the wiring manual)

The G/R wire goes back out to plug X-15 (driver's end of the dash) into the dash harness. From there it goes two directions. The first is plug X-07, which is on the passenger's side of the dash, not far from X-14. The engine harness plugs into this plug, and the G/R wire travels through that harness, makes a loop and down to the ECU, where it enters the ECU at terminal 1M. (schematic B-1d, page Z-34 in the wiring manual)

Terminal 1M corresponds to the "speed" terminal in the AVC-R wiring in schematic Z3-b. You should have connected to a green wire with a red stripe. If you didn't, that's your problem.

The G/R wire also connects to the cruise control module behind the driver's side kick panel, at plug Q-01, terminal E. (schematic Q, page Z-108 in the wiring manual)


jimlab 02-26-04 03:22 PM


Originally posted by machinis
Thanks a lot!!
No problem whatsoever. :D

Azaka 04-17-04 05:03 PM

Ok, so I got another gauge cluster to put in my car (because the tach on the old cluster didn't work anyways). Well the new tach works (yay) but the speedo still doesn't.

I also threw the stock computer back in, drove down the road and checked the code and the speed sensor was one of them, so I replaced the speed sensor with another one (not new, but had more resistance than the old one) and still not reading anything (this was before the gauge replacement).

If it's the wiring where would be the most likely place it would be? I'm really happy to have a working tach but it would be great if the speedo worked also.


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