Vehicle Speed sensors 98 ML320
 

My Emer/parking brake light just started going on. I then had Autozone scan the system as well as a local mechanic and they both read "failed speed sensor; poor electrical connection or short.

The mechanic says he will have to check all sensors, connections and wires. He says it happens and he's troubleshooted cars with the same problems before, mostly Chryslers.

Question, just for my knowledge how many sensors are there and where, and what kind of labor would I be looking at? Can I do this myself or leave it to an experienced mechanic?

Thanks much in advance,

What was the code?

Traction system has 4 speed sensors, engine has 2, & the trans has 2 speed sensors as well/

Printout from Autozone:

P0720

Definition
aa output speed sensor circuit
aa open or short circuit condition
probable cause
aa1 poor electrical connection
aa2 failed speed sensor

P0500

Definition
aa vehicle speed sensor circuit condition
explanation
aa the ECM has detected a fault in the vehicle speed sensor circuit
probable cause
aa1 poor electrical connection or short circuit condition
aa2 failed vehicle speed sensor
aa3 drive gear mechanical fault

The mechanic had a handwritten sheet of codes of which I couldn't remember. But he emphasized it was the CAN system and he would have to troubleshoot where the fault is. This is a independent shop and he related he had worked on problems like this before mostly on Chryslers.

Will the mechanic's printout narrow exactly where the fault is or is that a dealer specialty?