Trifecta question

[upallnight]

Originally Posted by Black-Forest

I have searched the threads but have yet to come across a reasonable solution to my DSC issue in our recently purchased 00' X5 4.4.These lights were on when we bought the vehicle. I've scanned the ABS system and found.

- Front right wheel speed sensor open circuit
- Front left wheel speed sensor open circuit

The above are hard codes and won't clear. I have replaced the offending front sensors with no success. I also get

- Steering angle sensor open circuit

This code resets with my Snap on Solus scanner but will come back when re-scanned a few days later. I also feel the Left rear sensor has an issue as intermittently I will loose the speedo. When the speedo goes out the brake warning light goes from amber to red. Speedo resets when the car is restarted. It seems odd to have so many "open circuit" codes. Charge rate average is 13.6V and does bounce around a bit but not below 13.2V and battery is new. I have a feeling it maybe time to replace the DSC module but thought I would check in with those who have experience this system. Any direction would be greatly appreciated.

The sensors that you replaced, did they look old or did they look new. Did the connectors from the wiring harness look new or look old. The fact that you said the connectors didn't fall apart lead me to think that they were replace at one time and like I stated before, the wire to the connector has to be install in a certain order in order for the wheel sensor to send a signal back to the module. It's like a diode, current can only go one way in a diode, reverse the lead and the diode won't allow current to pass. Same with LED lights, they can only be hook up one way unlike icandescent lights which can be connected any old way.

I replaced three wheel sensor on my X and in all three cases, the connector fell apart and I needed to install the wires into a new connector. My X was a southern car so it wasn't exposed to bitter cold salted road for most of it life.

[Black-Forest]

Considering the connector will only go all the way in one way it would be quickly apparent if you tried to install 180 degrees out as it won't seat all the way. I don't quite get the certain order thing. Are you referring to the connector has to be clocked a certain way?

[upallnight]

Originally Posted by Black-Forest

Considering the connector will only go all the way in one way it would be quickly apparent if you tried to install 180 degrees out as it won't seat all the way. I don't quite get the certain order thing. Are you referring to the connector has to be clocked a certain way?

The connector can only go in one way which is why the wires going into the connector has to be installed correctly. If a previous owner or mechanic didn't know that the wires needed to go in a certain way, if the connector fell apart and they replaced the connector with a new connector, they might have installed the wires incorrectly.

Think of the two wires in the connector as positive and negative. The connector is key so that you can only insert the connector one way so that the positive side goes to the positive side and the negative side goes to the negative side. If the connector was damaged because it was brittle, whoever replace the connector might have inserted the wires in the wrong position on the connector so now you have a positive going to a negative and a negative going to a positive.

The fault is for an open circuit in the wheel sensor, not an ABS module or DSC module fault.

[David.X5]

When you get several different wheel speed sensor errors at once, or the computer says the fault is moving around, I would consider the module. We very rarely hear about people getting actual module codes.

I do agree, especially since the vehicle was recently acquired, that I would check the connectors are ok and haven't been tampered with. People do funny things. Some PO on my car pried the trifecta LEDs out of the dash so it looked like there was no problem.

[upallnight]

Originally Posted by David.X5

When you get several different wheel speed sensor errors at once, or the computer says the fault is moving around, I would consider the module. We very rarely hear about people getting actual module codes.

I do agree, especially since the vehicle was recently acquired, that I would check the connectors are ok and haven't been tampered with. People do funny things. Some PO on my car pried the trifecta LEDs out of the dash so it looked like there was no problem.

That is one thing that I check for when I am looking at a car, to see if all the warning lights are lite when the key is installed. PO have been known to tape over CEL or SRS light or ABS light when they are selling a car so that the potential new owner will not know that there is a problem with the vehicle. I have also taken along my bluetooth scanner and my phone to check to see if any computer code has been reset to turn off a trouble code. Looking at the readiness cycle will tell you if they did that. You can talk them down or you can walk.

[Black-Forest]

Ah I see what you're getting at. I'm currently looking for a pin out diagram for the DSC and will add wiring diagram for the speed sensors to the list. I also noticed the BC button is not working as it calls up no data I assume because it uses the info from the DSC to formulate average speed, fuel economy etc. I did attempt reset by holding the button in but nothing showed up in the info window. Thanks again for the direction.

[Bmwtvboy]

I had the same issue on my 01,3.0 with 210K miles at the time. It turned out to be the ABS Module, then steering angle sensor and the right rear speed/abs sensor. Even though it all works now, I still get the 3 lights when I first start up and pull away. Disappears after about 50 feet. Good luck.

[upallnight]

Here's a link to a thread about getting the wires in the right orientation when you need to replace a wheel sensor connector.

http://www.xoutpost.com/bmw-sav-foru...tor-fixed.html

Here's a link to ECS if you need to buy a new connector

https://www.ecstuning.com/BMW-E53-X5-M54_3.0L/ES164858/

[upallnight]

Looking at the Bentley Manual, the No.1 pin is a solid wire color, and the No.2 pin is a wire with stripe colors.

[Black-Forest]

Thanks for the great info!