Code 1738 primary speed sensor code??

[nitrorocket]

Anyone get this code? Where is the primary speed sensor located. Truck apears to be in 3rd gear all the time. My scanner pulls code p1738.

The truck is a 2001 BMW X5 4.4L

[JCL]

Looking up code P1738 specific to BMW I get "pressure control solenoid C". That solenoid is inside the transmission, accessible in the valve body above the pan.

[nitrorocket]

When I look that up online I get the same rationale. BUT, my $300 engine scanner says exactly "P1738 Primary Speed Sensor"

I have an alldata account, but BMW keeps their stuff proprietery!! Grrr!!

My truck is in trans failsafe mode, I need to figure out what the reall problem is and replace it.

I am going to go out and try to check the wiring harnedd connections, maybe there is corrosion, I have heard of that before...

[JCL]

Unfortunately, that is your first problem, your generic code reader.

The speed sensor is inside the transmission case as well, near the valve body. You need to diagnose the transmission. If you want to open it up, you will require a proper service manual from ZF. You can test each harness, sensor, and solenoid. But it may not be an electrical problem, it may be a mechanical problem with an electrical symptom. A full diagnosis will be required to determine that. Also, I would look for heat related damage to electrical components inside the transmission as well as any obvious wiring harness problems externally.

There are some good threads on this site showing transmission overhauls on the ZF boxes.