code 1234 - speed sensor

[rlddlr53]

anyone ever get this code?

code 1234, I reset it, and it comes back with a cel every 20 miles or so

Any ideas?

[Adrian_Visser]

Who made your adapter? You need to hook up pin 14 on the c101 to pin 14 on the x20.

[rlddlr53]

did this happen to you before?

My speedometer works perfect, as everything else...

Who made your adapter? You need to hook up pin 14 on the c101 to pin 14 on the x20.

[Adrian_Visser]

It's probably number two on the list of most asked swap issues. Try searching sometime.

[rlddlr53]

I just searched online and couldnt find much. I saw on diagrams pin14 for both harnesses as you said.

My question is, I can still have a functioning speedometer as the signal is from the sensor in the diff, but at the same time have a bad connection between pin14 on c101 and x20?


I also forgot to mention the PO wired the car incorrectly, and my friend had to get the diagnostic port to work as I was getting a 1281 code, but no stuck with a recurring 1234

[Adrian_Visser]

Is your car an early model? Early models run the VSS (vehicle speed signal) and tach signals through a different connector.

It has nothing to do with making the speedo work.

The VSS going through the engine harness originates at the back of the speedo and runs either through c101 (late model) or c104 (early model)

[rlddlr53]

I have a late model, 89 325i with a s50b30us motor

[E30auddie]

Try driving it around easy for about 30mins/miles after resetting it. IIRC that's how mine went away. I think the ecu just has to get used to the new signals

[nando]

you need to check your C101 wiring. most likely the VSS just isn't hooked up.

[nando]

Try driving it around easy for about 30mins/miles after resetting it. IIRC that's how mine went away. I think the ecu just has to get used to the new signals

the signals are exactly the same. both the E30 and E36 use a 9-tooth diff/speedo sensor.

[rlddlr53]

PO had the wire from speed sensor to dme, not hooked up to the A side. Had it hooked up to O2s. Fixed, no CEL

[MattM]

sounds like quite the mess of a harness, speed signal hooked up to O2 sensor? obviously the PO didnt bother to crack an ETM and just went on some random pin to ping diagram, which obviously wasn't the right/good one.

is your O2 sensor hooked up correctly now too?

[rlddlr53]

Everything is working and hooked up right thanks to jahnaboi