Eliminating a CEL caused by VSS 1234 code SOLVED!

[2mAn]

Closing in on my appointment with the BAR and I cant really figure out why I cant clear out this code. Ive searched and theres chatter about the reading that comes off the diff, but by all accounts it looks like this should be a non-issue.

Then Ive also read it could be a wiring issue, but Im not sure how to verify if thats the problem. Im leaning towards this, but I have no idea where to start.

Car is an early model, OBD1 wiring harness is from a manual E34

[M3PO]

Well, the first thing you need to determine is if you are feeding the speed signal from the cluster to the DME. There is a green plug on the back of the (I'm assuming you added an i cluster with 7K tach) cluster that should have one wire going to the DME. I have an early model also and there wasn't a plug in my harness going to the green plug on the cluster, so I wasn't able to tap into any wire to get the signal. I ended up just soldering the wire right the the damn pin on the back of the cluster and then wiring it to the correct pin on the C101.

[2mAn]

Well, the first thing you need to determine is if you are feeding the speed signal from the cluster to the DME. There is a green plug on the back of the (I'm assuming you added an i cluster with 7K tach) cluster that should have one wire going to the DME. I have an early model also and there wasn't a plug in my harness going to the green plug on the cluster, so I wasn't able to tap into any wire to get the signal. I ended up just soldering the wire right the the damn pin on the back of the cluster and then wiring it to the correct pin on the C101.

I know for a fact there is nothing in that green plug ( if its the middle one IIRC)

My tach and all the gauges work, and Im also 99.9% sure that the blue and white plugs (the ones on the sides) are the only ones plugged in.


edit: Actually now that I think about it, there has been one random wire that Ive plugged in, but Ive pulled the cluster on and off so many times that I dont think I plugged it in last time I did it because it was always such a pain in the ass and I never knew what it affected (or is it Effected??).

Does it need to go into a specific pin in the green area because that wire (which looked like it is connected to an OEM connector) had a weird shape that would only fit onto one spot.

[2mAn]

So tonight I managed to have some time to take the cluster out. Nothing was hooked up to the green area.



Found this little guy hanging out just off the wire loom going to the white connector



So I hooked it up in one of the two spots on the green area and the only one that actually has pins sticking out.

Also discovered that this cluster has a blank spot with a panel for the check engine that all the late cars have. So now I know where to run the light.

Lets see if the reset will work.

[Coupelx]

Not sure what that does but the speed signal is on all 3 of the connectors on the far right side of the green thing in your picture. I pulled the wire out of the engine harness and ran it through behind the dash.

[2mAn]

Not sure what that does but the speed signal is on all 3 of the connectors on the far right side of the green thing in your picture. I pulled the wire out of the engine harness and ran it through behind the dash.

Mine would only plug into the top middle two and I plugged it into the one that actually had pins. I dont think I saw the light illuminate on my way to work this morning. Im about to drive 300+ miles later today so if it doesnt illuminate by tonight, Id say the problem is solved, but I wont hold my breath

[Coupelx]

What do you mean by "actually had pins"? They all have pins in them.

[Sh3rpak!ng]

That should do it. As was mentioned, all 3 of those slots output a VSS signal. I had to add an extra wire on there to feed my obd2 ECU in order for it to see some vehicle speed signal, but I don't think that's necessary for you as OBD1, I believe it goes through your main harness connector.

If not, you could always check the pinout for the ECU and just run a wire straight from the correct pin on the ecu to the cluster.

[2mAn]

What do you mean by "actually had pins"? They all have pins in them.

The two larger spots in the middle, not on the sides. One has pins sticking out and the other didnt.

That should do it. As was mentioned, all 3 of those slots output a VSS signal. I had to add an extra wire on there to feed my obd2 ECU in order for it to see some vehicle speed signal, but I don't think that's necessary for you as OBD1, I believe it goes through your main harness connector.

If not, you could always check the pinout for the ECU and just run a wire straight from the correct pin on the ecu to the cluster.

I havent plugged anything into those three slots on the side.

Lets say i DO need to add a wire and tap it into one of those three that are on the side, where does this wire need to run to? ECU directly, or back to the c101

[Sh3rpak!ng]

This is where you get the VSS signal from



I can't really comment on obd1 wiring since mine is obd2, but IIRC there is a vss signal wire running through your harness connector, which should trace through the harness to the ECU. If not, or if you'd rather be 100% sure you're giving the ECU the correct signal at the correct pin, look at the ETM for the ECU you're running, find the pinout for the ECU, and run the VSS signal wire directly from the grean cluster plug to the ECU pin. The ETM should show a pin that's defined something like "vehicle speed signal" and noted as an "input"

[2mAn]

Am I reading it right that its X20 Pin 14 and a black wire (or black/white) for the VSS? Ugh, I hate dealing with wiring stuff, and I was hoping to get to a point where I could look into hooking up the mpg gauge to function also, but this is a priority

[M3PO]

Am I reading it right that its X20 Pin 14 and a black wire (or black/white) for the VSS? Ugh, I hate dealing with wiring stuff, and I was hoping to get to a point where I could look into hooking up the mpg gauge to function also, but this is a priority

Yes, on my S50 it is Pin 14 (blk/wht). I ran a wire from the middle pin on the green connector to Pin 14.

Do you have a reduced rev limit?

[2mAn]

Yes, on my S50 it is Pin 14 (blk/wht). I ran a wire from the middle pin on the green connector to Pin 14.

Do you have a reduced rev limit?

Ok, cool, I will isolate that wire, but when you say you ran it to the middle pin are you referring to the set of 3 on the right, or the one that Im currently using?

No reduced redline, she will rev to 6800 (I think), the only weird thing Ive ever noticed is when I DO redline it, there is a slight hesitation for just a split second after Ive shifted gears. I rarely drive like a teenager so I dont think anything of it.

[Sh3rpak!ng]

yes, that's correct as mentioned. white/black pin 14. Simon, you can wire it to any of the 3 that are stacked on top of each other pointed to in red in that picture I posted. Those are all the vss signal outputs

[2mAn]

yes, that's correct as mentioned. white/black pin 14. Simon, you can wire it to any of the 3 that are stacked on top of each other pointed to in red in that picture I posted. Those are all the vss signal outputs

Cool, sounds like something I can (maybe) handle