2003 Dodge Ram 2500 5.7 — ETC failure is going to get me killed.

[fuxorsion]

As stated in title, I have a 2003 Dodge Ram 2500 with the 5.7 Hemi and electronic throttle control. It has been having a variety of issues with acceleration, including:

- sluggish acceleration
- surging throttle while driving
- stalling randomly
- extreme throttle response delay
- terrible gas mileage

I'm mainly concerned with the extreme throttle hesitation. The ETC light is always flashing in this case. Driving the truck is an absolute nightmare because once I let off the pedal at all (like at a stop sign or pulling into a parking lot), there will be absolutely zero response from the engine for several seconds no matter what I do. There will be cars waiting for me to go at a stop sign or something while I'm sitting there with the pedal mashed through the floor waiting for something to happen. By the time it finally responds, I might be launching directly into the side of one of the vehicles that got tired of waiting for me to go, at which point I have to slam on the brakes and block the intersection entirely until the f***ing thing will go. Nothing in my life has ever pissed me off like this truck.

I've tested both the throttle body and the APPS along with all the wires running between them and the PCM. I've checked the both 5V ref circuits along with grounds and sensor grounds multiple times. Everything checks out.

It always starts and idles perfectly. The flashing ETC light is completely random and will sometimes not happen for days or weeks. Other times it is constant. It doesn't appear to get better or worse no matter what I do.

There have been a number of codes that have come up, but the main ones are:

P0171
P2127
P2138
P2106

The LTFT is almost always maxed out at ~31.7% with the STFT sitting pretty normal with a slightly positive average. There are only two oxygen sensors. B1S1 voltage moves up and down normally between 0.1v and 0.9v. B1S2 seems to work intermittently. I've tried unplugging the O2 sensors and resetting the PCM, but it runs even worse then.

I've watched all the other live data, and it looks normal, but sometimes the timing advance will be 20°+ at idle while other times it will be ~10° at idle. I also noticed that the throttle position will sometimes read 0% at all times, but it doesn't seem to affect the acceleration. When it does read, it shows 8.62% and the graph follows along with the pedal like it should. I also discovered that if I unplug the APPS, it will still read a little over 1% for the throttle position, so it seems like there is some kind of stray voltage making it into the circuit or something.

I just figured I'd see if anyone here has ever heard of a similar nightmare.

 

[Jim BB]

not sure or even if these have them! but it almost sounds like a TPS (Throttle Position Sensor) if it does i would replace it and clean throttle body
Just my opinion

 

[Mercruth]

My thoughts too, throttle position sensor being ***** would check all your boxes.

 

[jws123]

I would replace the throttle body sounds like bad tpms and its apart of the throttle body and go from there its its probably origional from 03 they are not that expensive.

 

[fuxorsion]

Wow, I FINALLY have it fixed, and it's almost unbelievable what the problem was. The source of all my problems was a damn TENSIONER PULLEY! Tensioner pulley bearing to be exact. This morning my engine suddenly started chattering and sounded like it wasn't getting any oil to the top end, so I checked it out real quick only to find that the tensioner pulley was about to fall off. Once I removed it and got a closer look, I could see that it had been binding up for quite a while because the grease was all gone and the plastic material around it had melted. What must've been happening is that it was causing the belt to slip just enough at higher rpms to prevent the alternator from putting out the necessary current to keep everything working correctly, which is why the issues were so random and all the components/wiring tested good.

Thanks to those who responded, and I hope this helps anyone who finds themselves in this particularly frustrating predicament.

 

[E-Class]

I am going to remove my tensioner this morning. So I can take a look at it & if this happens to be the issue I've been having, I will be in utter shock. I've been chasing the same issue for the last 3 months now. This is the dumbest, hardest, & most elusive problem I've ever had. No DTC's, flashing ETC light, sensors seem to be performing & check out good, connections good, wiring sound, headaches many, frustrations maxed, solutions thus far 0! I apologize for the rant. I despise the ETC system & the lack of multiple fault indicators within the system to narrow the margin of possible faults & eliminate the laundry list of parts included in a single flashing lights warning indication.

 

[daniel van fossen]

I am going to remove my tensioner this morning. So I can take a look at it & if this happens to be the issue I've been having, I will be in utter shock. I've been chasing the same issue for the last 3 months now. This is the dumbest, hardest, & most elusive problem I've ever had. No DTC's, flashing ETC light, sensors seem to be performing & check out good, connections good, wiring sound, headaches many, frustrations maxed, solutions thus far 0! I apologize for the rant. I despise the ETC system & the lack of multiple fault indicators within the system to narrow the margin of possible faults & eliminate the laundry list of parts included in a single flashing lights warning indication.

Was this your problem? I'm dealing with this currently and the truck is pretty much not drivable.

 

[daniel van fossen]

Update-problem is fixed for now at least. I unplugged every harness from the pcm and left unhooked for probably 20 minutes. Applied dielectic grease to them and reconnected. Made sure they were in firm and truck started and runs perfect now. I'm thinking of having the pcm checked out though as this is the 6th TB in 2 years.

 

[fuxorsion]

Guess what, guys... The problem came back, but I think I'm making progress on solving this mystery entirely, and I won't stop until I do.

After replacing the tensioner pulley, the truck ran solid and smooth with no ETC light/limp mode for about 2 months, but then - much to my dismay - the problem started creeping back up and becoming a regular occurrence once again. Last week it was happening so consistently that the fault would persist even after restarting the engine several times, so I figured it was a good opportunity to take another shot at finding the problem.

My current theory is that the issue is not necessarily with the ETC components or system itself, but with entire electrical system. I think what's happening is that the PCM is particularly sensitive to rapid fluctuations in current, which can cause it to sense an ETC failure condition where there is none. Basically, if the serpentine belt slips on the crank pulley briefly due to fluid contamination, worn tensioner, worn belt, etc..., then the current being put out by the alternator will fluctuate rapidly, but the system voltage is maintained by the battery, so we would never notice. The PCM, however, has two 5V ref circuits that it's not only trying to regulate simultaneously, but which are compared and must correlate within the ETC system.

Since my wiring and componentry all tested good, but I was still getting an APPS correlation code, I decided to jump the 5V ref circuits together in order to sync and stabilize the inputs at the APPS with the hope that it would similarly affect the outputs.

That was about a week ago, and I haven't had a single instance of the ETC light flashing, limp mode, or any kind of code despite a couple of longer trips and driving the truck every day. I'm not proposing this as a universal or permanent solution, but it's progress.

I'm hoping some others here with this problem will try this out and/or give some feedback on my theory. I'll make sure to check back here regularly, so if anyone has questions or needs info, just LMK.

 

[jerryt]

After having replaced the tps and cps tw ice and replacing the throttle body and going over the wiring I have discovered that as soon as the ect light starts flashing, I put the truck in neutral, turn off the key, then start it back up it will be fine for the rest of the day. this usally happens every day within 2-3 miles. This isn't really a solution, but it's easy and I'm tired of fighting it.

 

[jws123]

I chased a ETC light on my 2008 wrangler for a whole month wasted about $200 in the end I found 2 large connectors for the main harness with water in them.

 

[2005DRAM2500]

Had this same lightning bolt light problem on my 2005, 1500.
Bought it new in August of 2006. It was the last 2005 on the lot. It was a great truck except for that one problem. Dealer tried umpteen times to fix it.
Throttle bodies, gas pedals, complete wiring harness change. No joy. It would hold for a day to maybe a month and it would come right back. I insisted on them putting in a new ECM, but they refused. Last time under warranty, the dealers most experienced mechanic took my truck home for a week and drove it.
When I got it back a week later, light was off, cab reeked of cigarettes and tank was on empty. Nice huh?
That repair held for 4-5 months and everything that you have said above came back. It was never fixed. I lived with it. Truck was t-boned in a terrible accident that my son and I were lucky to escape alive. 19 year old ran a stop sign at 40+ MPH and flipped us over. It was bad. So, in my experience, If you have a lightning bolt light that will not remain off on a Chrysler product.......get rid of it because mine was never solved under full warranty by the so-called experts.
In that way, the truck was a lemon. But it was reliable and never left me stranded.
156K on the clock. She's in Dodge Ram heaven now!