02 dakota 3.9l v6 4x4. The truck doesn't want to shift at right rpms in first and 2nd. Also dies sometimes when letting off gas coming to a stop. I pulled the codes P0500. I have also replaced the rear wheel abs sensor, PCM, head light switch and ignition switch. I haven't replaced RWAL because it tested good. Anyone else having this problem and has fixed it? I found a harness connection in driver inner wheel well that looked wet. Idk if this could cause problem. Running out of ideas and money

 

2 or 4 wheel ABS? How many sensors do you have on the rear axle? 1, 2, or 3? Are there sensors on the front wheels?

 

2 wheel abs I believe. Only abs sensor is on differential on rear axle pumpkin

 

1 sensor on rear axle on pumkin

 

Check and see if you are getting 5 volts back to the sensor. (ignition on, engine doesn't have to be running.)

 

P0500 is vehicle speed sensor, it should be on the transmission. It reads how fast the transmission is turning to know when to shift, requires I *think* a 1 1/8" deep well socket to remove (may just be a 1" been awhile since I swapped this). The ABS sensor (ontop of the rear diff) controls the speedo up to about 35mph and the ABS. If it's dead, the ABS/Brake lights come on and speedo won't work until ~35mph. Letting off the gas and dying sounds like the IAC, it's on the back of the throttle body under the air hat. You can clean it and the passage, but be gentle and do not move the plunger while it's out.

Breakdown in order:
1: Remove airhat and throttle body: Clean throttle body, IAC port, and IAC. This /should/ fix your stall when stopping, if not, try replacing the IAC. (it controls air flow for idle, if it sticks closed, when you let go of the throttle, it chokes the engine)
2: Replace speed sensor on the transmission, should fix your shifting and P0500 code.
3: If shifting is still erratic, check TV Cable tension, replace TPS.

Recommended that you grab some CRC contact cleaner and clean every harness on these sensors and use dielectric grease to prevent corrosion.

 

It all checked out 5 volts and correct resistance too. When I pull the connection off the RWAL no other lights go on. Maybe replace that? Or there's a connection in the harness in driver wheel well on frame rail that has crack and wet...possibility?

 

Also, for the airbag light, does your horn or cruise control (if equipped) work? If not, that's likely the clockspring. Otherwise, check the yellow harness under the driver kick panel, it's the airbag line.