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View Full Version : Speedometer issues persist after sensor replacment, cluster test, and wiring test



Dollarbill425
01-08-2016, 12:59 PM
1994 325i
Last week my speedometer jumped to 60 then past 160mph while driving home, I knocked on the front cluster and the issue corrected itself until the following morning when it shot past 160 and stayed there until coming to a stop at which point it came back to zero. After taking off again it shot past 160 again but at this point I was on the freeway and the engine began to cutout whenever I went past 60mph (estimated) then power came back when I slowed down, giving me the idea the speed limiter was being activated due to a bad speedometer sensor in the diff. I've replaced it with 3 different sensors now all with the same result and checked for corrosion on the contact pins. Each sensor also was emitting voltage when I turn the wheel, I didn't record the voltage but it did change with speed. I've checked wire continuity to the cluster and its good, and also used the cluster test to verify the needles working as they should (they all go up and down as they should). What am I missing here? No check codes, no abs light. Do the wheel speed sensors even come into play on an e36 model speedometer? I've looked at the wiring schematics and didn't see a link to them but I'm at a loss here. :help

*Odometer is also off and was calculating a 1/4 of a mile as 1 mile or more.

E36328Coupe
01-13-2016, 03:05 AM
If you have an 18 button OBC does the same thing happen to digital speed in the hidden menus ?

Dollarbill425
01-13-2016, 07:48 AM
Unfortunately I don't have the 18 button obc. Drives just fine under that 60+ threshold.

Dollarbill425
01-21-2016, 01:29 PM
I wanted to make sure I updated this thread as I have found many online threads with this issue with no return answer. Replacing the cluster fixed the issue.

JDStrickland
01-21-2016, 04:11 PM
POINT OF ORDER
The speedo is driven from a speed sensor on the differential. The wheel speed sensors only compare the tire speed relative to the other tires to decide if the ABS needs to be activated or not. The actual speed of the car is determined by a sensor in the diff that is looking at the ring gear.

You fixed the problem, but your first post says you inspected and tested the wheel speed sensors and they appeared to be okay. You missed the one on the diff.

Dollarbill425
01-21-2016, 07:25 PM
Actually my intial post covered me replacing the sensor in the diff with spares that I had which verifed the problem wasn't with the speed sensor. I wanted to clarify that the wheel speed sensor didn't come into play like some other threads suggested so (I believe the post ended up being about an e46).

hide1
01-21-2016, 09:34 PM
This guy found the solution to my problem. Saved me $$$. Mechanic said it had to be a new cluster of course. It might have some useful info.

http://www.bimmerforums.com/forum/showthread.php?1260098-crazy-instrument-cluster-switch-on-off-himself