Hey folks I'm just about ready to loose my mind with my 2002 Dakota 4wd. First off I have been chasing the ABS and brake light on at the same time. I have replaced the brake light switch, the abs sensors, and the rear speed sensor. The light is on 95% of the time but occasionally it goes off. Last month I think I drove 30 miles with it off.

Additionally I have a cylinder 3 and 5 misfire and the truck sometimes gets stuck in second gear. If I shut the truck off and restart is works fine of a while but can get stuck in 2nd at any moment. I have also replaced the transmission module on the transmission.

When I called AMCO transmission repair today they told me to drive it in but they suspected the issue is electrical.

Based on the random transmission thing and the 3 and 5 misfire (with new plugs and wires) I am guessing that the ECM/PCM might be bad after having done some research on the module itself.

So if it is bad or intermittent will it also throw those ABS lights on? I cannot seem to find a full diagram for the 43 module connections.

Lastly based on some of the scans I have had there were no codes.....but the misfires could be seen.

A module coded to my truck is only $249 which seems like a deal considering that I have to drive all the way across town to even have the transmission shop look at it.

Oh and one last thing.....they want to charge me $169 for a scan of the computer locally

I need some really smart advice here.

HELP!!!!!!!

HK

 

Check the fuse for the ABS system. Verify its getting power on both sides of the fuse and then check the underside for damage. When the ABS system faults it will illuminate both the brake and the ABS light. Might be a damaged/corroded wire somewhere in that system. As for the misfires, what all have you replaced on that side? Just the plugs and wires? Did you check the injectors? Also just because its new doesn't mean its good. Using a volt meter check the resistance in the known good ones and then compare to the misbehaving cylinders. Make sure to bend the wires while doing this. Any clicking or sparking noises coming from the engine around there? The 2nd gear thing sounds like limp mode. You probably can get it up to about 30 MPH at the absolute highest right? The computer is one of the most reliable systems in a car. Unless you have something explicitly pointing at it, its likely not the cause.

 

All the fuses have been checked on the car. They are all good.

When I did the plugs, wires, cap and rotor and also put the battery terminal back on there was no misfire and the truck ran perfectly for about 10 minutes when it started to idle rough again (3 5 misfire). The truck also gets really bad gas mileage....somewhere in the order of 10-12 mpg.

On the second gear issue correct.....about 30 mph or so. I have to shut off the truck and restart it. Another issue is when id does shift normally it's when I'm light on the gas. Hard acceleration causes the transmission issue. I also believe the truck has stuck in 3rd some of the time.

Thankfully all of my bad guesses have not been too expensive yet. It's a 20 year old truck......and all of the local chain automotive repair shops as well as the dealer charge you like it's a european luxury car.

I needed a $7 transmission gasket replaced that they wanted $240 to do.......sure it took 7 quarts of fluid for $22 but stuff like that is pretty steep for 30 minutes worth of work. A transmission service on my 2018 Audi is less than that at the dealership.

Thoughts?

 

Which motor do you have again? The 5.2 and 5.9's get about that much MPG if not a bit more unless you drive with saving fuel in mind. Have you tried unplugging your o2 sensors? You might have a bad TPS considering limp mode seems to be triggering from increased throttle percent. Do you have a basic scan tool with OBD2 data stream support? If you do, look at the throttle percent and compare to what your actually pushing on the pedal. Otherwise you can get a TPS pretty cheap and they are super quick to install. Try to get a Mopar one if you can as the aftermarket sensors are not known to be top notch. Also I vaguely remember seeing a post on here about cleaning them by drilling a really small hole in the plastic and spraying it out with electronics cleaner.

 

Also clean up your IAC [ idle air control] ,an get that injector tester tool .Sometimes a good throttle body clean up helps misfires.I had one an that cleared it with the clean up . ..On shifting issues maybe pull the tranny pan an see if anything is in it.The accumulator spring can impact shifting an breaks a lot in dakotas. [ easy to replace once pan is dropped]..



Its a good idea to update it all if your in there along with the filter.
An adjust the bands..

 

Motor is the V6 3.9
We will see.

HK

 

Tell them for that price i can buy a scanner and do it myself! You have 3 issues, the ABS you need to see what is throwing the code for it. The stuck in second could be a bad TPS sensor. The misfires could be injector problems but i would look and see if your plenum gasket is sound(it can cause multiple mis fire codes). If you suspect injector issue change the position of the injector to another cylinder and see if the code follows it. Then you know there is an issue. You can get scanner that reads live data and gives you ABS codes for cheaper than $169. Might want to see if any small repair shops can check it for you for a fraction of that price. If you think you can handle the task yourself look for a scanner that reads live data/ABS codes.

 

Have you replaced the crank position sensor? My 3.9 would throw 3 and 5 misfires when the sensor went bad., I used a parts store sensor and it didnt go away. I got an OEM sensor from the dealer and the misfires never came back.

The plenum gasket is also a good consideration for evaluation.

Also, check the two grounds on the firewall directly above the valvecovers.

 

I would also be curious as to just what plugs you put in there. These engines really don't care for the rare-earth fellers. (platinum, iridium, unobtainium.... etc.)

 

Unplug your CT sensor and see if the mis-fires come back. Your 3~5 minutes of running perfect and then mis-firing sounds like open loop vs closed loop. If the mis-fires do not come back with the CT sensor removed then consider replacing map, crank & cam (if it has a cam sensor, I think not). Both of those sensors do not last forever and degrade over time.