Yesterday I replaced the TPS in my truck and the truck still ran funny, so I remembered that when you replace the TPS you have to reset the PCM by disconnecting the positive battery cable and putting the key in the on position for 30 sec. then put the cable back on and start the car. However, when I now my truck won't start. I wants to but no matter what it doesn't start. Is there something that has to be reset in the PCM or something else I have to do before it starts? Thanks for any help.

 

To reset the PCM you should disconnect the negative battery cable and hold the key in the start position for about 15 to 20 seconds. When disconnecting and reconnecting the positive cable it is easy to blow fuses. Start by checking all the fuses, beginning with the fuses and fuse links in the Power Distribution Center next to the battery. Also be sure that you have the TPS installed correctly and it is plugged in like it should be.

Jimmy

 

So you should turn the key to the on position while the - is disconnected? What does that actually do? There is no power in the truck.. Just curious.. ????

 

You disconnect the negative battery cable and hold the ignition key in the start position for 20 seconds or so. This procedure completely drains any residual voltage out of the PCM and provides a complete reset on the PCM. Simply disconnecting the positive battery cable will not reset the PCM. PCM has capacitors inside it that store voltage and energy even with the battery disconnected and they have to be bled down to fully reset the PCM.

Jimmy

 

That makes since.. so even after being disconnected for 8 hours you think the PCM has enough capacitance to last that long? I might just do that.. sorry for the nube-tube question.. Used to ford.. just diconnect the older ones at least, for about 1 hour and then pop it back on.. even check engine light codes clear for a little while..

 

Ok so I missed typed in the first post I actually did remove the negative cable. However when I started the truck up today with a jump from a friend it the RPMs still fluctuated when idleing. I also let the truck warm up for like 5 minutes then it seemed fine. So I decided to test it out and started to drive, but when I came to my first stop the truck unexpectedly stalled out. Then, it wouldn't restart and I had my friend help me jump start my truck again. This time I couldn't start the truck without giving the truck some throttle and it would stall if I didn't keep the throttle depressed. The fuel pump does work because I hear it when I turn the key in the on position. Now I'm stumped as to what the problem is.

 

A few things to check, start with the battery. Dakota's are very sensitive to low voltage and will not run right and sometimes will not run at all if the battery is even a little low. If the truck won't run long enough to get it to the parts store, remove the battery and alternator and take them to Autozone or Advance. They can do a load test on the battery and can check the alternator's output for free. If you need a new battery, the Duralast Gold at Autozone is about the best one available for a reasonable price.

Check the battery cables and connectors for corrosion and bad connections, replace the cable ends if need be. Skin back the cable insulation at the battery cable terminal ends and check for corroded cable there too. Also, Dakota's are also super sensitive to bad grounds. A bad ground will cause a lot of problems for you. Be sure that all the ground connections on your truck are clean and tight.

Your truck might be different but on mine there is one ground cable connection on the block in front of each valve cover. One is behind the coil and one is behind the heater bypass tube. Remove the bolts and connectors and clean the connector and the ground itself with solvent and a wire brush. You want clean shiny metal on both sides. There is also a ground lug connector in the driver's fenderwell behind the battery, and there is one on the frame, behind the left front tire. There are also ground lugs in each kick panel inside the cab. You want clean shiny metal on both sides of all ground connections and nice bright clean copper wire on the battery cables at the battery terminals.

There is also a posssibility the new TPS is bad. Turn the key to ignition on/run, but do not start the engine. At the center wire on the TPS connector there should be about .50 to .75 volts with the throttle closed. The voltage on that center wire should slowly and steadily increase as you open the throttle plate by hand. With the throttle wide open, you should have about 4.5 to 4.75 volts on the center TPS wire. Anything different and you should exchange your TPS for another one.

It sounds like the truck has some kind of electrical problem. Check your electrical system very thoroughly and carefully. Electrical problems, battery and ground problems and low voltage problems can cause a lot of driveability issues on Dakota's.

Jimmy

 

So, I checked the battery and its good, the cables are nicely connected, the grounds are good, the TPS is good. Is there anything else it could be besides an electrical problem?

 

Not trying to hijack post.. but I'm not one for breaking the seal on the connector..

Most docs show to test the Ohm resistance of the TPS.. anyone know those default figures and where about they should be?

Mine starts out around 3.651 (ish) and ends WOT 1.xxx..

 

I have one quick question on this. I tested my T.P.S. and I got about 3.8 volts at W.O.T. Does that mean i should replace it? Thanks.