bad ABS control module leading to speed sensor malfunction?
 

So my sister had her 2000 maxima se AT diagnosed by a shop with the california state financial assistance. The problem is her car throws a check engine light because the speedometer isnt working. Speed sensor code. The shop said their is no sensor in the tranny as I also searched for hours trying to find it with no luck. The ABS light is lighting up on the dash. They said the speed is read through the abs wheel sensors. They are ruling the ABS control module bad. is this true? the car runs fine passes emissions but fails because engine light turns on during smog. If they one knows how to fix this speedometer problem or knows the location of the abs control module or the part that really needs to be changed that would be great. ANY HELP WILL BE GREATLY APPRECIATED THANKS

According to the FSM, there's a revolution sensor in the trans that makes a signal for the TCM, which then sends a VSS signal to the ECM for the p0500 code. ABS sensor is nothing involved

I agree with Philbert579. Last year I had my speedometer and an ABS sensor go bad. These two incidents were completely unrelated. The ABS sensor lit up my TSC and SLIP lights, the speedometer just required a replacement of the gauge cluster.
Through these problems I discovered that there is indeed a revolution sensor in the trans. Not sure where, but it exists and it probably is your issue. Take it to a Nissan dealer or someone with the Consult/Consult II computer.

Take a look at the 2000 Maxima FSM. AT page 218. You'll see the picture of where the revolution sensor is and how to troubleshoot it.

I guess you did a typo - it's page 281 in the AT section. (AT-281)

Actually page 281 is just a picture. Page 114 is the diagnostic.

I guess it depends where to look. I was referencing this FSM http://www.nicoclub.com/FSM/maxima/2000/at.pdf it is page 218 "VEHICLE SPEED SENSOR A/T (REVOLUTION SENSOR)".
However you are correct too if looking at this FSM: http://www.nicoclub.com/FSM/maxima/2000.5_Maxima/at.pdf "DTCP0720 VEHICLE SPEED SENSOR A/T(REVOLUTION SENSOR)". It is page AT114. Original poster indicated that his sister has a 2000 SE, that is why I pointed to the 2000 FSM.

I have been aware that there are different versions of the manual and I checked the 2 versions that I have and they are both page 114. So you made me aware of a third version. Since you kindly provided links, I went and investigated this 3rd version.

On the front page of the manuals (the FWD section), nissan prints some identifying information.

For the first production 2000's (VINs up to YT0 12236, YT2 11680, YT5 27429, or YT7 40491), I have the manual:
edition: April 1999
revision: June 2000
publication no. SM0E-1A33U3

nicoclub has:
Edition: January 2000
Release: December 2000 (01)
Publication No.: SM0EGF-1A33E0E
MAXIMA QX
NISSAN EUROPE N.V.
Produced in The Netherlands

For the later production cars, both nicoclub and I have
edition: November 1999
revision: January 2001
publication no. SM0E-1A33U5

It appears that nicoclub got their hands on the European version of the manual. This version of the manual may be just fine, but I would be leery of the electrical wiring diagrams.