Check Engine Light, No Fault Codes

[SkorcherX]

Hey Guys,

I just recently completed my M50NV swap. Car runs great, everything appears to be in order. Except ever since I have completed the swap I have had a flashing CEL.

The other day I was able to get the ECU scanned to see what it was complaining about. It threw the following code:



I have ran the VSS from the green plug on the back of the instrument cluster over to the ECU. The car appears to run great.

So I cleared this code thinking that my CEL would go away, and if it did not, then I would check the fault code again to confirm that the same code is being thrown.

The CEL is still flashing after I cleared the code. When scanning again the OBD scanner says that there are no codes.

What could cause the CEL to flash if there are no codes faulting?

[Thrizzle]

You didn't wire up the cel light correctly at the c101?

[SkorcherX]

Maybe I can get a confirmation on how it should be wired.

1987 E30 325e Check Engine diagram:


1992 E36 325is Check Engine Diagram:


This would lead me to believe that I need to connect the Gray wire from the E36 DME to White/Black wire on the E30 side.

So in theory I should be able to inspect my C101 and see a White/Black wire (car side) connecting to a Gray wire engine side. Sanity check please.

And just to play devils advocate... If I have these wired correctly is there anything else I need to check?

[328ijunkie]

If its on in key on and off (or on if you have an issue) while its running it sounds like the CEl is wired right. As far as the VSS goes, how did you wire that exactly?

[SkorcherX]

If its on in key on and off (or on if you have an issue) while its running it sounds like the CEl is wired right. As far as the VSS goes, how did you wire that exactly?

The CEL comes on when the key is on. The CEL flashes when the car is running. I'm like 90% sure if this. Will confirm when I leave work.

The VSS...

I ran the wire directly from the DME, behind the dash to the green plug on the back of the instrument cluster. This thing below:

[328ijunkie]

^ Good. But what wire did you run there lol

[nando]

be careful with the green plug. on the surface, it looks like they're all VSS signals. but they are not - one pin is a ground and the other is 12v, and some don't connect to anything at all. only one pin is a VSS.

[SkorcherX]

Which pin should it be connected to? Based on the graphic below (which I used as a reference when wiring it up) it appears any of the three on the right will suffice.

The wire was Black/White

[SkorcherX]

So I confirmed after work... With the key in the ON position the Check Engine Light flashes. Once the car is running it continues to flash.

The Oil Service Indicator works... I was able to reset that and get the green lights to light up. Pretty sure the two are mutually exclusive.

So either I have the VSS wired wrong hence the code... But it doesnt really explain why the DME doesn't continue to throw fault codes after it was cleared assuming the problem (VSS?) is still present.

All suggestions welcome. Thanks!

[Thrizzle]

My vss isn't hooked up, and the cel isn't on. If that helps any.

[SkorcherX]

My vss isn't hooked up, and the cel isn't on. If that helps any.

I was unaware that this could be ignored. I could have sworn that without a VSS that the car would not rev past around 3500 RPM's. Am I misinformed?

[nando]

Which pin should it be connected to? Based on the graphic below (which I used as a reference when wiring it up) it appears any of the three on the right will suffice.

The wire was Black/White

You are probably OK then. some of them look different depending on the production date. just beware, that not every pin on that green connector is a VSS. :)

have you tried any of the factory BMW scanners to see if they pull anything?

[mentaleeill]

cel should be at pin 12 on the c101 according to the etm on wedophones. the diagram you showed, has the active check control highlighted, which should be for the overhead check panel, not cel.

[mentaleeill]

as shown here

[SkorcherX]

have you tried any of the factory BMW scanners to see if they pull anything?

I have not. I would imagine I need to take it down to the dealership to have it scanned. Pretty curious what kind of looks I will get.

I just pulled back the C101 plug cover and confirmed that the Gray wire from the DME is pinned to #12. Just as the schematic shows in the pic mentaleeill posted.