TCS/DSC and ABS light on but no codes

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2010 Mazda 5 Sport
Hello Everyone. This issue is for a 2010 Mazda 5 Sport/automatic/215,xxx miles.

A couple nights ago I drove the car to take my son to work. On the way home I stopped to get gas. When I started the car to leave the gas station, the lights came on and did not go out. On the way out a few hours later, the lights were still on, but then went out after shutting the car off and back on again. To be specific, the actual DCS LIGHT is NOT on; just the ABS light and the TCS/DSC (car skidding icon) lights
Same thing next night; they came on and I was able to get them back out again, this by taking a little risk and shutting the car off while in gear (walking pace), then stopping. Once I started the car, put it back in gear and drove off, once the trans made it's "clunk", the lights went out and all was well.
I put my code reader on it tonight and there were no codes present.
Same thing happened just now and I was able to do the same thing again (shutting the car off while in gear (walking pace), then stopping. Once I started the car, put it back in gear and drove off, once the trans made it's "clunk", the lights went out and all was well).
Also tonight, for a brief moment, the speedometer was not reading the correct speed.. I just happened to notice it, as I'm pretty sure I was doing around 40mph, but it was showing 25mph, then it jumped up to show the correct speed. It never did that again.
Of course, with the TCS/DSC & ABS lights on, cruise control is also disabled (and right before a long distance trip this weekend!) LOL.
The car appears to shift normally and other than the lights, drives normally.
Since there are no codes, I don't want to go buy ABS sensors because I don't know which one to replace.
What else can I check? Does the 5 have a VSS (Vehicle Speed Sensor) and if so, where is it located?
Thanks for any guidance you can offer.
 
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UPDATE:
Went to 2 auto stores this morning to see if they could pull the codes.. OReilly's was a joke as their reader was even more basic than mine. Luckily, there's an Autozone right across the highway and had better luck there:
Codes:
C1142-A0: Right Front Tone Ring Missing Tooth Fault
C1234-A0: Right Front Wheel Speed Sensor Input Signal Missing
So I'll check and make sure the sensor is clean and go from there.
 
UPDATE:
I took the wheel off and checked the sensor wire and it was intact. Disconnected the wire from the sensor and removed the retaining bolt for the sensor, but was unable to remove the sensor itself (it's the original one!) so rather than force it and damage it, especially since I hadn't ordered the part yet, I sprayed some contact cleaner on the assembly and in the "space" where the ring and leading edge of the sensor should be. That didn't clear the light, so I'll order the part and go hard next week. I'll probably do the driver's side one as well.
 
Completely forgot to update:
UPDATE: sensor replaced, test drive and light is out. Went ahead and replaced the front left sensor as well. All good now.
 
Thanks for the update!

We need to force regulation on car manufacturers to put a simple numeric display in cars that show codes for all the computers in the car. It's beyond ridiculous at this point.
 
Glad you got it sorted out. I was going to ask if you’d pulled the knuckles off of the axle recently. I loosened mine when I did my front struts to get a little more give to wrestle the strut off, and didn’t get the knuckle 100% back on the spline. Threw the same codes which went in and out as you had because it sometimes got to where the sensor could see the teeth, and sometimes didn’t.
 
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