Wheel Speed Sensor issue

[mike4slund]

Hello all,

I recently purchased a 2000 740iL Super nice, love the car. I used to have a 98 740i and the engine took a poop on meh. Anyways, on the 2000 740iL. Speedometer doesnt work. All three lights on in dash. I hooked up scan tool and read code. Left rear speed sensor not transmitting signal. So, ordered and replaced wheel speed sensor. First time I started the car, all 3 lights out. (Did not get a chance to drive) started car next day. All 3 lights on in dash and no speedometer still. So i uplugged sensor and do not have 8 volt reference voltage at LR. I do not have at RR either, but RR works fine and shows wheel speed on scan tool. My question is how can i condem the module? i have the wheel well removed and all wiring looks intact. any pointers on how i could track the issue down?? Ive cleared the codes and tried. still get left rear no transmit signal code.or how can I test the integrity of magnet for sensor that's in the bearing/hub

[setconstr]

2 things I can think of, Did you clean out the sensor hole before you put in the new one ? lot's of crap was in mine also did you buy oem ? lots of folks have had problems with after market

[mike4slund]

Nothing in the hole that I could see. I did blow out with air. I did buy OEM. Resistance value of this sensor matches that of the right rear sensor. And that of the original sensor.

[Frankie]

Unless others chime in with contrary advice, I'd say there is absolutely nothing wrong with your speed sensors. Instead, you have a faulty brake module giving you bogus readings. It'll need to be rebuilt. Send it to Module Masters or similar. I had the same experience with my E39.

[Sundaycruzer]

Unless others chime in with contrary advice, I'd say there is absolutely nothing wrong with your speed sensors. Instead, you have a faulty brake module giving you bogus readings. It'll need to be rebuilt. Send it to Module Masters or similar. I had the same experience with my E39.

+1

[Mayorchuck]

Swap the LR and RR sensors and see if the speedo works. RR works the cruise. As stated though, all three lights often indicate the module is bad.

[mike4slund]

Swap the LR and RR sensors and see if the speedo works. RR works the cruise. As stated though, all three lights often indicate the module is bad.

I put the LR in the RR spot and still showed wheel speed.

This brake module is attached where all the brake lines meet correct?

[Mayorchuck]

Confused. The idea is to put the passenger side sensor in the drivers side to see if the speedo works. If you did this and it does not, the culprit is probably the module. Yes, on the location of the module.

[mike4slund]

I already had LR pulled out. So I placed in LR spot and still had wheel speed. Which tells me that the LR is working. So putting RR in LR spot wouldn't be necessary if I took LR and put in RR spot and the RR still functioned.

[Mayorchuck]

Sorry,I thought we were talking about you test driving each time and the speedo was now working. Here is the best thread I know of on the subject if you haven't seen it:

https://www.bimmerfest.com/forums/sh....php?p=4205801

[mike4slund]

Thank you. I will definitely read that.

Here's an update.

Started the car this morning. Everything worked perfectly. About 5 minutes later. All three lights came on and no speedometer. . I'm convinced it's the module at this point warming up and stop working.

[Timm]

Yes, that's normal behaviour for a failing module - as is reporting false error messages - more info here:

https://www.meeknet.co.uk/E38/ABS/Index.htm

[mike4slund]

0265950001

Does the replacement have to match the above part number? I found one that is a 0265950002. I have programming capabilities so that's not a big deal.