Ok so I have posted here before and you all answered my problems. I have done some reading as well. I had the P0720 and p0500 codes pop up. I replaced both sensors and the problem was fixed, for a while. Thing is, I just replaced them again because it was doing the same thing. I start the truck up and get going everything is fine. About a mile down the road the speedo either drops to zero or rolls over to peg out at 120. either way, truck wont shift. Also, my abs and brake light are constantly on.

The truck is a 2000 Ram 1500 Quad cab w/ 5.9L auto.

My question is: Is there any other reason the truck would be throwing the same codes for a brand new sensor? And is there anything else I should try checking?

 

Sounds like a NO-BUS issue. Try pulling the plug from the ABS module on the left front fender and inspect it for water,or corrosion. Clean it and plug it back in. If it does it again,try resetting the computer by removing the positive cable for 20-30 secs(timing is important). If this doesn't do it,I have another trick....... This is assuming that all your grounds and wiring have been checked already.

 

I don't recommend removing the positive cable..... same thing can be accomplished by removing the negative battery cable, with much less potential for excitement.

 

well, I cleaned the grounds, the abs is clean and dry and i reset the computer codes via a scanner. I still have the lights on.

 

How do your brakes work? Good pedal height? Not soft, or spongey? Fluid level up to snuff?

 

I agree,go over the obvious first. Check the harness out good for possible heat damage or crushed wiring. A good visual solves alot of problems. It could be possible one of the hubs are bad throwing a conflicting signal.

Let me ask this. After you do the scanner erase of the codes and go thru the next key on cycle, does the ABS and brake light come on during the ABS self check, or do you have to acctually drive it in order for the light to come on?

If the light doesn't come on with the computers self check at key on, then the sensors are probably fine, but what's tripping the light is then on the mechanical end of the sensor. Sensor ring in the diff or bad hub bearings depositing metal on the front rings, loose wiring, bad wiring, you name it. You just have to find it.