I just joined this forum and am glad to be here. I need help bad. I changed the battery cables on 2003 5.9. because the cable weren't long enough, i routed them close to the firewall because they wouldn't reach on top of the radiator. They're from
customcables.com and i believe they're for an earlier model dodge diesel. After I got them installed. I took the truck halfway to Las Cruces, NM about 30 miles. That when I noticed that I had no cruise control and it wouldn't shift into overdrive. the indicator on the column show circles only in park & neutral. So I'm pretty sure that it's in transmission limp mode. The engine runs fine it will run up to 50-6o but the rpm's are around 2500. I don't know if I did something stupid by putting the cable up by the firewall. It doesn't seem to be near the PCM. I didn't band the cable to any wire bundles. I checked all the grounds I don't know where to go from here. The local O'reilly's manager (pretty knowledgable) told me it's usually a dealer issue. Not being made of money, I can't afford for the dealer to put in a new transmission then find out that wasn't it.Any ideas? This happened when I changed the cables so I don't think its anything else like sensors. By the way, I have no codes with the key thing plus my programmer.I put it back to regular tune from economy mode. It didn't change anything/still in limp mode.
I originally put this in the help thread but i think it more appropriately goes here

 

I'm wondering if you pulled a connector loose that goes to the tranny? Check all your connections.....sounds like something stupid. Maybe the auto guys will post up soon. Mines a 6sp man, but all else is close to the same. Double check your battery connections and also that the batts are up good and charged. Only other thing I'd try is to take the programmer all the way out and test drive again.

 

I have a wire that was inside the plastic conduit that goes to the starter and it has a connector up near the front of the truck on the drivers side.
It comes from down by the starter. it is a small gauge wire. Do you know what it goes to? possibly the transmission? I'll have to check & see if its disconnected. Where do most of the transmission wires go to from the PCM? My truck is at another location, I'll check the color of the wire when I can.Thanks for your assistance.

 

I hope you have better luck then I am right now, My 03 is doing the same thing with the indicator and stuck in 3rd gear so it seems. Just had the Governor pressure solenoid & transducer replaced with no luck :s

 

I just don't want to throw money in it not that I have money to throw.I sounds like yours is in limp mode also. I would see if the dealer will refladsh the PCM. This one here in El Paso will do that without trying to replace more parts. My only problem is that I don't know if it will go back in limp mode after I get it done. The PCM posdsible needs to be replaced. I guess I did some thing when I changed the cables.The dealer also told me to disconnect both the positive & negative cable for one complete hour to let it reset the PCM. I'm gouing to try that next.You might want to try that also.

 

check out my thread: Hard start, ruff idle, knocking, no power
im thinking that my issue is that the dealership unlocked my new ECM without clearing anything that may have been left behind from the bad 1, TCM still thinks its broke?

 

Here are a few definitions I found helpful in understanding whats going on

EMERGENCY RUNNING FUNCTION
In order to ensure a safe driving state and to prevent damage to the automatic transmission, the TCM control module switches to limp-home mode in the event of critical faults. A diagnostic trouble code (DTC) assigned to the fault is stored in memory. All solenoid and regulating valves are thus de-energized.

limp-home mode: This is a fault mode in which the transmission either loses electrical power or the PCM deactivates all of the electronics. The transmission will default to max line pressure. The driver will have Reverse and 3rd, with manual 2nd available by putting the gearshift in 2 or 1 (doesn't matter). 1st, 4th, and TCC lockup will not be available. It will not hurt the car to drive it like this for short periods, but use manual 2nd to get the car moving, and be aware that the trans will generate more heat than normal while operating in limp-home mode due to increased torque converter slippage during 2nd gear starts and no lockup in 3rd gear.

 

this may or may not work, not a fix but more of a band aid:
"I ended up jumping the transmission relay from slot 30 to slot 87 and everything works again. Now I just need find out why it won't allow the relay to activate. Relay is good so I'm thinking maybe a short between the PCM and fuse/relay box?"

I just remembered reading some where that there are 2 wires going to the passenger side battery that supply a pcm ground that may have got bumped or wiggled while you wher changing wires, there are connectors or some kind of joiner on the wires that may cause limp mode issues.

 

I'm going to go look at the truck tonight. I only have one small wire going to the ground on the pass. side. I don't remeber two. I also am going to look for any loose connections & unhook the battery cables completely for one hour to see if I can get it out of limp mode.
If that doesn't work its scheduled to go to a highly recommended
non-dealer diesel guru here in El Paso.
On your truck you talk about replacing the ecm.Was it bad also? I just thought you had limp mode in the transmission only. mayby i'm just comfused. It happens a lot lately.

 

the micro processor in the ECM fried, after replacing the ECM the truck is now in limp mode, not throwing any codes either, im assuming the TCM still thinks the truck is still broke, may require another trip to the dealership

 

Well, I tried it last night, disconnected for over an hour looked for loose disconnected wires, etc. notrhing, still in limp mode. Its going to the mechanic tonight to have the transmission codes read. I spoke to the manager of the o'reilly where my son works.They seem to know the good mechanics. He referred me to a real good diesel mechanic near me supposedly this guy's the best. He told me he'll read the transmission codes for free and go from there. Maybe you could ask around at your parts store for a good diesel mechanic, instead of going to the dealer.It sounds like they never really fix the whole problem until they've replaced a lot of parts. We'll see how it goes tonight.

 

Tried disconnecting my batteries also with no luck. Keep in mind I live way up North, A good diesel mechanic is unheard of around here, we no longer have a transmission shop and the dealer is 100kms south which gets expensive on towing bills but don't have a choice. The mechanic that has it right now is near the dealership, im confident he'll find a fix even tho his code reader will not communicate with my truck. Im assuming those fancy computers that can talk to your engine & tranny are extremely expensive.
Keep me posted on what you find out, thanks

 

The mechanic that was going to read the transmission codes put me off for a week. so i went to one that had done work on my daughters car and our gov't cars on the past. he told that his code reader could not communicate with my truck either. I'm going to drop it off on Sunday for him to look at it next.He's always been pretty good with us and I trust him so we'll see what happens. almost sounds like our trucks have the same problem. I'll keeo you posted some time next week.As long as you trust the dealer, maybe it will work out.

 

Here's the latest: the mechanic I went to told me that ythey put in another computer that they had on hand and it did the same thing, stayed in limp mode. Also he said my wiring looks like it had been changed, before I bought it. He referred me to someone else again who works on Dodge diesels only. The machanic who put me off last week, i called him and he's busy but coincidentally he referred me to the same guy the other mechanic referred me to. ZHopefully this is the one. I'll keep y'all posted

 

Finally fixed my limp mode, turned out it was the "skim fuse", which explaines why nothing would communicate with it. 3 shops and no 1 checked the fuses. I showed up at the shop with my tester in hand determined to find out whats wrong, after the mechanic telling me hes at a loss and basically gave up on it, pluged in new fuse and bam back to normal. Drove it home, washed it, reloaded my smarty #4, started perfect. Pluged my DR.Performance chip in to piggy back with smarty and *** starts acting up like it did when the ecu went. ITS A NEW ECU ....NOT AGAIN!!!!!!!!!!