steve crout

I've read many posts in this forum and been able to remedy a lot of little problems so thanks to all those who participate!
The one that has me stumped on my '01 RAM 2500 5.9ltr 24 valve (359,000 kms) auto trans with new fuel and air filters, is a combination of issues. I recently replaced the camshaft position sensor according to the error codes I picked up and next came the dead pedal for a split second (when cold) and what seemed like the transmission not being able to decide what gear to go into.

The charging system is running a little high all the time at around 14.5 to 15 volts (according to the gauge) and when cold, the system charges high for a moment then goes back to 12 V then up to 14 and 15 V back and forth for a few minutes then settles down and stays at 14.5 or 15 V.

It runs fine at an idle, starts OK and is either on or off - no rough running. This goes on for a short while until the engine warms up. Once everything is warm it runs like a champ. Fuel use is about 13.5 ltrs per 100 km. There are no engine codes flashing but there is a code that comes up when I do the key on/off process - P0 122. This suggests the APPS but the other issues that happen with it are making the diagnosis difficult. I haven't tried resetting the APPS yet and can but the strange charging cycle has me bugged.

I appreciate any suggestions!

Steve in Summerland, BC, Canada

oliver foster

The "strange" charging cycle is your grid heaters doing their job.
That is what they do when it is cold out. They draw a lot of electric power, to the point where you can hear the motor load up, the light dim and the gauge drop.

Nothing to worry about.

BarryG

Yes as Oliver mentioned those grid heaters take some juice. IIRC they are 90 amps each so total 180 amps. The wait to start light can be on for up to I think 30 seconds depending on temp then once started they cycle on and off depending on IAT temp up to 180 seconds or something like 23 mph if you start driving before they stop cycling. You can just watch the volt gauge swing up and down and more less each couple of swings is a bit less than the previous one.

I see this is your first post at least on here one other thing is if it has been enabled and it probably has once the grid heaters shut off if the IAT temp is still low enough it will kick into high idle after I think it is 30 seconds. If it is really cold (cant remember temp it activates) after another 30 seconds of high idle it will kick in the 3 cylinder high idle which will scare the crap out of you if you aren't aware of it as it sounds really bad but it is only running on 3 cylinders to help it warm up quicker. Touch the brake and it will shut off the high idle.

oliver foster

I have only seen 24Vs run high idle and kick into running on three cylinders if they have a Smarty programmer installed like my '99 I am running.
Stock trucks or ones with other programmers I have not seen do this. My old '01 with an Edge Attitude with Juice programmer never high idled or ran on three, and I started that in -30F before.
Yes the first time one kicks into running on 3 cylinders, it gets your attention.

steve crout

Thanks for the quick response. That settles the question about the charging rate going up and down.

Anyone have any thoughts about the transmission seeming to shift up and down all over the map and the dead-pedal issue? Would they be a related issue?

oliver foster

I am a manual transmission guy, so I can not comment much, other than I bet it is not related in any way.

Greg Reed

Check your alternator for AC feedback. You can find Utube videos on how to do this and there are good write ups and articles on www.mopar1973man.com.

s-cube

Clean your battery and ground/chassis connections. The electrical systems on these trucks are finicky. I can tell that it's time to clean the connections when it hunts for a gear and gets an occasional dead pedal.

steve crout

good tip - thanks. I did the 2 negative battery leads earlier but not the ground source so I'll hunt them down next.