Speed Sensor

[Aaron Bakos]

Does the speed sensor input for the OBC and the speedometer/odometer?

My OBC always reads the correct speed, but speedometer/odometer will act a bit wild after the car has been driven for ~20min, then settle in at double speed on the speedometer. The odometer also reflects the higher speedometer reading. I was assuming that the speed sensor fed both systems, so if one is working properly, logic tells me that it's not the sensor.

I posted last week about capacitors and I was considering changing them out, but in the spirit of starting simple, I would rather change out a part that doesn't involve a circuit board.

I'm getting close to admitting defeat and paying someone to diagnose it :(

[bimmerd00d]

weird, mine does the exact opposite.

[Aaron Bakos]

Well, if I figure it out, I'll let you know after the party :)

[gale]

Mine used to have no tach & the speedo would read about 1/2 of what it should on cold mornings after sitting overnite, even more likely on a Monday if it sat all weekend. Later in the day when restarted it would work fine. A new battery took care of it even tho the old battery passed a load test.

[Aaron Bakos]

Hrm...my problems started after my battery died down low when the car sat for a couple weeks.

Interesting.

[freeparking]

Hi, im Al, new to this thread. Dont feel alone. I have a 92 525 100k and have the same problem. I bought a differential speed sensor and will be installing it this weekend. As for the capacitors, my board looked different from the one on Brunos site. I did take the board out and ordered 2 capacitors for replacement. The 2 sizes you need are 1.) 1000mf 16v 105degree 2.) 220mf 16v 105degree.
They do not carry these capacitors at radio shack, but email me and i will send em to you.(email) netrubicon@yahoo.com. I will also let you know if the capacitors fix it. I will switch them out tomarrow. Ill let you know or send an email

Net.

[Kalevera]

My speedo's been erratic for a while. At first, it just didn't work. Then, it would flash on/flash off. After a mechanic pulled the cluster to test it, it worked fine until I had to jump start the car due to using the radio while I was working on the car one day. It hasn't come back since (been a week). I pulled the connector and sprayed some contact cleaner - everything looked fine there and it didn't change anything. I've got a new(er) cluster and will be getting a new diff sensor tomorrow, so between the two, I hope to solve the problem.

I haven't figured out how to get mph from the OBC, so I don't know if that part's getting the correct info. I suppose that'd help me determine which part is at fault, possibly. (my understanding is that the OBC gets the info from a plug on the instrument cluster?!).

best, whit