Speed Sensor Issues

[chazsandiego]

Hello all,

I'm on the verge of solving a longtime issue and I need some opinions on the matter.

My cruise control hasn't worked since getting the vehicle. I initially thought it was the obvious broken cruise control throttle cable but a replacement module did nothing to remedy the issue and with all fuses functional I didn't know where to go next and forgot about it.

My check engine light had been throwing code 1222 (O2 sensor). Replacing the sensor solved my rough Idle issues but shortly after I began to get the CEL intermittently. This time code 1221. I figured it was my no name sensor having problems and pulled and Bosch sensor from the junkyard. It too would throw the CEL intermittently, code 1221. The computer reset trick resolved the issue temporarily, even cleared the codes, but that didn't last.

This morning on my way to work I notice that my speedometer is bouncing/glitching at idle.

A cursory Google and forum search leads me to believe that my speed sensor could be behind at least two if not all three issues. Although I could be completely wrong.

I'm curious if anyone else has had any similar issues that may have been caused and resolved by that speed sensor. Saw a Shogun link to that e34 site and the process seems to be a fairly simple P.I.T.A.

Thanks!

[shogun]

clean the speed sensor and check the wiring connections at the speed sensor http://www.bmwe34.net/E34main/Mainte...eed_sensor.htm
code 1221 https://www.bimmerforums.com/forum/s...gine-code-1221

check for air leaks.

[kce1900]

Two years ago I had some weird issues: speedometer was working, odometer was not, fuel consumption was not displayed in the cluster, but ok in the OBC. And sometimes everything was working fine. Cruise control was working mostly, but sometimes it would disconnect. This didn't make any sense to me since all of these functions depend on the signal from the speed sensor. It turned out that the sensor's connector was hanging on the last two strands of wire. Soldering it back on solved the problem.

The speed sensor is rather primitive. It contains a magnet and a reed switch. Dirt should not affect it unless your differential is full of iron shavings. So yes, check the wiring and the connector.

[chazsandiego]

I greatly appreciate the feedback! That is pretty much what I wanted to hear.

I've been battling my girlfriends 03 Hyundai Elantra for the past week which has really cut into my bimmer time.

Hoping to have some time Monday to check that sensor and close this thread.

Thanks again!