2001 Cruise Control Issues

[K-ris]

Short Summary: Bought the truck a month ago for a good deal (2001 24v w/ NV5600, shortbed.) My 1st diesel.

 

Problems started with. AIRBAG light, reverse lights always on, cruise light on, leak from xfer case and also one on the motor. At this moment I am left with a leak on transfer case and cruise light as of yet.

 

New servo, brake light switch, ran the middle wire to clutch pedal, clockspring and checked cruise buttons for function. Also found no substantial power from pin 6 that crosses through the brake switch to the servo.

 

No go, called dealer after noticing too many flags of a hack job conversion. SO pump, hacked wiring harness and writing on the PCM like it was a junkyard computer. Dealer said the PCM isn't from this truck and is a tranny swap.

 

I heard 2001 nv5600 Cummins are vacuumless cruise, so what you think is wrong? Will PCM/ECM driven cruise run a vacuum servo cruise? What I am clueless is when I ran the NSS to the clutch, there was already a connector wired from a harness (yellow wires) to the clutch switch. I could not combine them, it wouldn't work. So I jumped the yellow ones and put in place the NSS on the clutch switch. Two safety switches???

 

Thanks in advance, spend a lot of time with no results.

[dripley]

Pretty sure both the 01 and 02 manual trucks are fly by wire cruise, 5 or 6 speed. Trying to make it work with what you have is above my pay grade.

[K-ris]

Mine to, so I have drawn a upside-down white flag.

[trailhead]

I struggled with my 01 6 speed cruise control for a long time.  The guys here were right all along.  I don’t know what’s exactly going on with your truck, but I strongly suggest taking the AC noise problem seriously and do the ground mod.  Lots of electrical problems that you would never guess will be resolved right there.  

[K-ris]

AC noise, I hadn't mentioned anything like that... Unsure if this a cross post somehow.

[dripley]

The WT ground is highly recomended for our wnd gen trucks. Did mine couple years ago maybe anc it will cut the AC voltage from the aternator makes the 2nd gens act up. Cruise control is one sytem the AC noise can mess with. The mid us listed at the top of the powertrain forum. It may help yours, dont know. You have some unknowns with your truck.

[trailhead]

Alternating current noise from your alternator.  Long story short, after replacing and checking so many things trying to get my cruise control to work correctly, I replaced the Functioning ecm.  But the new ones kept failing instantly.  After three new ecms I finally replaced the functioning alternator.   Haven’t had an electrical problem since.  Cruise control works as designed.  If you click on my profile you will find the thread where I describe all of this in detail.  But yes if you aren’t familiar with AC noise and it’s effects on these trucks and you have electrical issues, you’ve come to the right place.  Don’t underestimate the AC noise issue

[dripley]

6 minutes ago, dripley said:

The WT ground mod is highly recomended for our 2nd gen trucks. Did mine couple years ago maybe and it will cut the AC voltage from the aternator that makes the 2nd gens act up. Cruise control is one sytem the AC noise can mess with. The mod is listed at the top of the powertrain forum. It may help yours, dont know. You have some unknowns with your truck.

 

Sorry for the double post. The first one was typed so bad l could not read it.

@trailhead is definiely right on ac noise. 

Edited September 27, 2020 by dripley

[K-ris]

Alright, about to dive in. So, bad alternator??? Charges fine, but interference? Does that mean I could try disconnecting the alternator to troubleshoot.

[trailhead]

 

That link should get you moving in the direction of AC noise issues.  I’ll keep chiming I with knowledge from my experience but when it cones to procedure, other guys here have incredible expertise, so I have to leave it to them.  

[K-ris]

Thanks all, I need to land a good vm, my craftsman AC is all over the place

[K-ris]

Well.... measured on my buddies Fluke. AC .01V, so CC still is a no go.

[trailhead]

Replacing my pcm didn’t solve my cruise light issue.  Dripley had said it was an Ecm issue and was right.  I was told my ecm was for an automatic.  Again, you need more technical help than I can provide, but if sharing my experience helps, I’ll do it.  

Edited September 29, 2020 by trailhead

[K-ris]

Yeah I was leaning towards ecm or pcm myself. My truck is an SO, so it likely is an auto ECM.

[trailhead]

Ya. Dealership told me my pcm should be replaced.  That didn’t do anything except lighten my wallet.  

[dripley]

7 hours ago, K-ris said:

Yeah I was leaning towards ecm or pcm myself. My truck is an SO, so it likely is an auto ECM.

5 speeds came with SO pumps also, just like the autos. The 6 speeds came with the HO pumps.

 

The reman ECM on mine caused the CC light to stay lit whenever the truck was on and the cruise did not work. The second one that is, the first one failed to work at all. Always figured the second was for an auto but after 3 months of being down I had to use the truck. Drove it for a year with no cruise until that ECM failed. The new ECM I got after that with proper programing solved my issue. As best as I know the PCM reads the signals from the sensors and relays the info to the ECM and it sets the cruise speed.

 

I am speaking of a factory set up vehicle. If it has been retrofitted to manual tranny, the wirings hacked and an unknown PCM installed, I dont know what you have.

[K-ris]

Truck was 2001 Dodge 2500 Auto Cummins SO, now if is a 2001 Dodge 2500 6spd Cummins SO.

 

How would I choose and ECM, likely a 6spd ECM. Pretty sure my PCM is a 6spd with original harness, that I have finished the conversion correctly I believe.

[dripley]

1 hour ago, K-ris said:

Truck was 2001 Dodge 2500 Auto Cummins SO, now if is a 2001 Dodge 2500 6spd Cummins SO.

 

How would I choose and ECM, likely a 6spd ECM. Pretty sure my PCM is a 6spd with original harness, that I have finished the conversion correctly I believe.

Well thats part of the problem. You have an SO engine. The tranny does not make it an HO if has just been retrofitted. I am not completely up on the engine diference but I think the pistons are slightly different along with some oil cooling but not positive on that. The VP is different for sure and the programing for the ECM is different between the HO and SO. Hopefully someone who knows better can add to this. 

 

It is possible you could have the ECM and PCM flashed for a manual tranny and have the fly by wire CC. That almost sounds to easy though.

Edited September 30, 2020 by dripley

[Mopar1973Man]

On 9/23/2020 at 9:06 AM, K-ris said:

Problems started with. AIRBAG light, reverse lights always on, cruise light on, leak from xfer case and also one on the motor. At this moment I am left with a leak on transfer case and cruise light as of yet.

 

Airbag light is most likely the clockspring in the steering column.

 

Again the clockspring takes care of the cruise functions. It's a variable voltage. Say like 1 volt does one function, 2 volts does another, etc. There is 5 volts in that line but the cruise sends back different voltage message for each function. 

 

Transfer case is easy just remove from the truck and split the case open and seal the mating faces again. Then there is a front seal and a rear shaft seals just pull the out and replace. Make sure there there is no wore groove in the shafts.

On 9/23/2020 at 9:06 AM, K-ris said:

heard 2001 nv5600 Cummins are vacuumless cruise,

 

Fly by wire cruise basically the throttle signal is sent from the PCM directly to the ECM. No vacuum motor used being there is no automatic transmission with a Throttle Valve (TV) to pull. Since the only reason for vacuum direct cruise is the automatic transmission. Now if the PCM is the wrong one it will send out on the 4 wire plug. there is roughly 50 some odd software version per year for the PCM. Wrong software on just one module makes all kind of weird issues. Both the ECM and PCM should be matching years and should be matching VIN wise too... I know several have done swaps of modules but it has to be done right. 

 

I've used Auto Computer Specialist to get my PCM replaced after my alternator fried it. Provided me correct VIN number and even proper software for my year, make and model. They even have a harness repair there too so you could send in your harness and have it repaired like new!

Edited September 30, 2020 by Mopar1973Man

[K-ris]

Wow, thanks for chiming in. Anyway to send PCM and ECM to be reflashed to correspond to a converted NV5600 with SO pumped 2001 Truck?