Truck went into limp mode with "ETC" warning light - stored P2122

[Bullfrogg]

I have been having similar issues for about 3 weeks now. After driving for 15-20 minutes, the "Service Electronic Throttle Control" alert pops up and it goes into limp mode and maybe more. Speedometer stops, 4wd stops, Cruise stops, etc. Also, if I put the truck in park, it will not go back into gear. If I turn the truck off, it will not start again until it has had enough time to cool down. Anywhere from 5-60 minutes, depending on how long I drive in limp mode.

I took it to a dealership the Tuesday and they recommended replacing the ABS Control Module. Which is on backorder until April of 2024. Attached is a copy of the DTC readings. Not 100% sure I agree with that, especially after looking at others with similar issues, but no clear signs of a fix.

I called around and one dealership told me of a place called Module Masters in Moscow, Idaho that will rebuild the ABS module if I take it off and send it to them. I haven't called them yet to see though. Still looking to see if it could be something else.

 

[Jebb]

A follow up for anyone interested/having a similar problem:

I purchased a new Hella brand accelerator pedal and sensor assembly for $60 (including shipping) from Rock Auto. Looks identical to the factory part in every way.

After installing the new part I started the truck and the check engine light immediately went off. I didn't even need to clear the DTC codes (P2122) with the scanner.

On checking I found that the old, factory pedal had a clicking sound near the center of it's travel and also some roughness/scratchy sounds in other parts of its travel - so it seemed pretty obvious there was something wrong with it internally. The new pedal assembly is smooth over its entire mechanical range.

I am not 100% certain because I've only driven for a few miles but, so far, this repair looks promising.

 

[huntergreen]

Hope it works out for you, but I believe OE electronics are the way to go.

 

[Jebb]

...but I believe OE electronics are the way to go.

May I point out that the OE part failed - and at only 18,000 miles. I could buy another one of those from the dealer for $250 and hope it lasts or I could buy this Hella replacement part for $60 and hope it lasts. The decision was easy.

 

[huntergreen]

May I point out that the OE part failed - and at only 18,000 miles? I could buy another one of those from the dealer for $250 and hope it lasts or I could buy this Hella replacement part for $60 and hope it lasts. The decision was easy.

I understand the economics, but this forum is full of posts from members that used aftermarket parts that failed right out of the box, and these are known brands that used to have stellar reputations. I hope you’re one of the luckier ones that proves me wrong. Keep us updated.

Also, keep Benny in mind if you ever buy mopar parts.

 

[Jebb]

I understand the economics, but this forum is full of posts from members that used aftermarket parts that failed right out of the box, and these are known brands that used to have stellar reputations. I hope you’re one of the luckier ones that proves me wrong. Keep us updated.

Also, keep Benny in mind if you ever buy mopar parts.

Well - it seems it is NOT fixed. Truck went into limp mode again last week with chime and CEL immediately on start up. I shut it off then re-started and it ran fine. I got to where I was going with no issues but then on my return trip it went into limp mode again less than 1/4 mile down the road.

Got home. Went in the house. Came out and re-started to take it to the dealership and it ran PERFECTLY the whole way there (30 minute drive).

Dealer has had the truck for a week now and can't find anything wrong with it. They've check the APPS and it's good. Road tested several times and cannot duplicate the failure. Could be another 500 miles before it fails again. Or 5 feet.

So now what? An intermittent failure that just started happening for no apparent reason. If there's a bad harness or connector somewhere it was probably bad from the factory (truck only has 17,000 miles on it). I haven't touched anything since the last oil change about 6 months ago. No other codes or symptoms.

The truck is now completely untrustworthy. Have no idea when or where it will fail again. What happens if I'm on the freeway doing 70mph and this thing decides to go into limp mode? Not a good scenario, especially here in Los Angeles where most of our freeways have no shoulders...

Any suggestions?

 

[huntergreen]

Well - it seems it is NOT fixed. Truck went into limp mode again last week with chime and CEL immediately on start up. I shut it off then re-started and it ran fine. I got to where I was going with no issues but then on my return trip it went into limp mode again less than 1/4 mile down the road.

Got home. Went in the house. Came out and re-started to take it to the dealership and it ran PERFECTLY the whole way there (30 minute drive).

Dealer has had the truck for a week now and can't find anything wrong with it. They've check the APPS and it's good. Road tested several times and cannot duplicate the failure. Could be another 500 miles before it fails again. Or 5 feet.

So now what? An intermittent failure that just started happening for no apparent reason. If there's a bad harness or connector somewhere it was probably bad from the factory (truck only has 17,000 miles on it). I haven't touched anything since the last oil change about 6 months ago. No other codes or symptoms.

The truck is now completely untrustworthy. Have no idea when or where it will fail again. What happens if I'm on the freeway doing 70mph and this thing decides to go into limp mode? Not a good scenario, especially here in Los Angeles where most of our freeways have no shoulders...

Any suggestions?

I don’t really have any suggestions. What year is your truck ?

 

[Jebb]

I don’t really have any suggestions. What year is your truck ?

2017

 

[Jebb]

OK folks - really hoping for some advice here. The dealer has had the truck for 10 days now and still can't find the problem. I don't know if they are actively working on it or not at this point. I need my transportation back!

What do you guys advise?

I replaced the Accelerator Pedal assembly which, AFAIK, is the #1 cause of P2122 - but that, apparently, was NOT the problem. Could the problem be on the other end, i.e., with the throttle body? Every time the truck has gone into limp mode it has been while idling - pulling up to stop lights, etc. Maybe the throttle plate is dirty/sticking? Or maybe the battery voltage dips a little? Just guessing here but so is the dealer....

@RamCares - I need my truck. Any help appreciated!

BTW - if the dealer can't diagnose the problem can they still charge me the $250 diagnose fee if I pick it up un-repaired? Or does the truck have to sit there until they give up - and in that case how long can they keep it?

This is the second serious issue I've had with this truck that they couldn't diagnose. The other problem - which still exists - is the braking-on-a-slope issue I posted about here: ttps://www.ramforum.com/threads/white-knuckle-moment-steep-driveway-hard-brakes-not-stopping.128905/ I probably should have pursued the Lemon Law back then.

 

[huntergreen]

Alright Jeb, the way I see it, your choices are 1) talk to the dealer and see what they can do to fix this.

2) try a different dealer.

3) try a private mechanic.

4) trade it in.

I’d lean to suggestion 1 and if no resolution offered, I would use suggestion 3.

 

[Jebb]

Alright Jeb, the way I see it, your choices are 1) talk to the dealer and see what they can do to fix this.

2) try a different dealer.

3) try a private mechanic.

4) trade it in.

I’d lean to suggestion 1 and if no resolution offered, I would use suggestion 3.

Thank you for the input. All good suggestions.

The dealer just called and conceded that they cannot find the problem. He said the next step in their procedure is to start replacing parts, beginning with the pigtail connector to the APPS - for $700. He said that it MIGHT be the cause but there is really no evidence to support it. I asked if the mechanic wiggled the connector and wiring while the engine was running. He said yes but it threw no codes. So, IMO, that seems an unlikely cause. He agreed but said that's the next step per "their book".

I can't spend $700 on another "maybe" solution.

Now - one final piece of info. This issue started happening right around the time I stopped driving it regularly for any significant distance. It's 6 years old and has 17,000 miles on it. Most of those miles were long trips (60 miles+) but in the past 3 months my trips have been short (only a couple of miles) and only once a week or so.

I've never had any trouble starting the truck but is it possible that short trips aren't fully replenishing the battery between starts? It seems a little far-fetched but the dealer did say there were some low voltage codes stored (that my scanner didn't pick up for some reason). Maybe they happened since I took the truck in or maybe they were stored back when the battery was replaced 6 months ago, IDK. He said they cleared all those codes and they haven't come back since.

So, is it possible I just need to drive it more often and for longer distances? Seems an unlikely cause but is it possible?

Will try that first then follow up with #2 or #3 if necessary. The problem with those solutions is finding someone who can diagnose this and not just charge me again for chasing no conclusion.

 

[BWH101]

good afternoon. I want to first say I’m new to trucks.
I have a 2004 1500 5.7
Runs good however out of nowhere the lightning bolt️ lights up. No not able to accelerate. However when I shut the truck off and start it back up it’ll run fine( for a while). Any idea what’s going on?

 

[NETim]

good afternoon. I want to first say I’m new to trucks.
I have a 2004 1500 5.7
Runs good however out of nowhere the lightning bolt️ lights up. No not able to accelerate. However when I shut the truck off and start it back up it’ll run fine( for a while). Any idea what’s going on?

You should probably post this to the 3rd gen forum.

Good luck and welcome to the forum!

 

[PA Ram]

Thank you for the input. All good suggestions.

The dealer just called and conceded that they cannot find the problem. He said the next step in their procedure is to start replacing parts, beginning with the pigtail connector to the APPS - for $700. He said that it MIGHT be the cause but there is really no evidence to support it. I asked if the mechanic wiggled the connector and wiring while the engine was running. He said yes but it threw no codes. So, IMO, that seems an unlikely cause. He agreed but said that's the next step per "their book".

I can't spend $700 on another "maybe" solution.

Now - one final piece of info. This issue started happening right around the time I stopped driving it regularly for any significant distance. It's 6 years old and has 17,000 miles on it. Most of those miles were long trips (60 miles+) but in the past 3 months my trips have been short (only a couple of miles) and only once a week or so.

I've never had any trouble starting the truck but is it possible that short trips aren't fully replenishing the battery between starts? It seems a little far-fetched but the dealer did say there were some low voltage codes stored (that my scanner didn't pick up for some reason). Maybe they happened since I took the truck in or maybe they were stored back when the battery was replaced 6 months ago, IDK. He said they cleared all those codes and they haven't come back since.

So, is it possible I just need to drive it more often and for longer distances? Seems an unlikely cause but is it possible?

Will try that first then follow up with #2 or #3 if necessary. The problem with those solutions is finding someone who can diagnose this and not just charge me again for chasing no conclusion.

Did this ever get resolved? I have a 2018 with 57,000 miles and never had an issue anywhere close to what you're experienced,but am curious as to what could have caused it. Only weird issue I had was one morning leaving for work I remote started right before heading out to my truck to give it a minute or 2 to warm up. When I went outside it sounded louder then usual. I have a Flowmaster FlowFX muffler,but it seemed to rumble a little more. Started driving and seemed loud and then check engine started flashing which isn't good. Power seemed way too low as well. Pulled over shut it off and checked for codes, and don't think any came up (this happened in the spring). Started back up and drove a little bit since I was going to work and it started running normally. Never found out what caused it and it never happened again even while towing which I do April through October for camping trips. Still bothers me that I don't know what caused it. Most likely was cylinder misfire, but not sure why and why it never occured again.

 

[Jebb]

Did this ever get resolved?

Cause was never determined. I don't know if it applies to gas or just diesels but I did the PPS recalibration procedure on the new PPS and, so far, the DTC hasn't returned. I believe the dealership may have flashed the PCM as well because it feels a bit different then it did before (shift points, etc.). Or maybe the new PPS fixed it, IDK. We'll see...

 

[huntergreen]

Cause was never determined. I don't know if it applies to gas or just diesels but I did the PPS recalibration procedure on the new PPS and, so far, the DTC hasn't returned. I believe the dealership may have flashed the PCM as well because it feels a bit different then it did before (shift points, etc.). Or maybe the new PPS fixed it, IDK. We'll see...

What is PPS ? Thanks.
Never mind, clicked on your link

 

[Jebb]

It is now March 9 and the truck has been running fine since my last post to this thread (3 months).

But on my way home today, while waiting for a left turn, the "lightning bolt" came on and the truck once again went into limp mode. I checked the DTCs and, sure enough, it showed the same code as all the times before: "P2122 Accelerator Pedal Position Sensor, Circuit D low".

We could blame this on the aftermarket APPS I installed after the first occurrence but it did the same thing with the OEM part - so now I'm thinking it's something in the wiring, connectors or maybe even the PCM.

EVERY time it has done this (4 times now) it has been while the truck was in Drive and idling (sitting at a stop light, etc.). As I posted previously, the dealer had it for nearly two weeks and could not duplicate or find the problem. With 3 months since the previous failure their inability to duplicate in one week doesn't surprise me. Their next suggestion was to start throwing parts at it which is guessing at my expense and unacceptable.

After shutting down and restarting the truck runs normally (but with check engine light/DTC stored). So whatever is throwing that code is intermittent and not a hard fail.

So how to find/fix this? Anyone know a good electrical diagnostic shop in North Orange County CA?

 

[GTyankee]

I only has the Lightning Bolt come on 1 time.

I have been sitting at the Calexico California/Mexico Border
The Ram was shut off well in the ACC position while i listened to the Radio.
After about 2 hours, the semi truck that i had been waiting on drove across the Border.
As the semi was going through Border Inspection, i started my Ram, the Lightning Bolt lit up.

The Semi & I drove back to San Diego, he signed off the Invoice & i drove directly to the dealership.

The dealership told me that the Computer just got confused.
That next time, i should shut the Ignition OFF, before starting the
Ram, when the ignition has been in the ACC position for a while.
That light never showed up again

 

[aszumilo]

This may or may not help, but, in my old truck (2004 Ram 1500 Hemi) it would sometimes take anywhere from 5 minutes to 1 1/2 hours to start. The truck had about 25k miles on it.
The symptoms I had were:
1. When I put the key in and went to start, none of the gauges would move, for 5 minutes to 1 1/2 hours.
2. Once the gauges popped on, the truck would start and would be in limp mode.
3. Shutting it off and restarting it would drive fine
4. Took it to the dealer 3 times for the problem, but, they could not duplicate the issue, so, they just cleared the codes.
5. The 4th time it happened, I drove it all the way to the dealer I bought it from, where I knew the Service Manager
6. They put the scanner on it and determined it was the computer.
7. Computer replaced and I never had another problem from there until I totaled it at 202k miles.

 

[Jebb]

This may or may not help, but, in my old truck (2004 Ram 1500 Hemi) it would sometimes take anywhere from 5 minutes to 1 1/2 hours to start. The truck had about 25k miles on it.
The symptoms I had were:
1. When I put the key in and went to start, none of the gauges would move, for 5 minutes to 1 1/2 hours.
2. Once the gauges popped on, the truck would start and would be in limp mode.
3. Shutting it off and restarting it would drive fine
4. Took it to the dealer 3 times for the problem, but, they could not duplicate the issue, so, they just cleared the codes.
5. The 4th time it happened, I drove it all the way to the dealer I bought it from, where I knew the Service Manager
6. They put the scanner on it and determined it was the computer.
7. Computer replaced and I never had another problem from there until I totaled it at 202k miles.

Thank you for the info but I have a somewhat "less severe" problem. The truck always starts and runs fine but then for no apparent reason all of a sudden goes into limp mode while driving with "lightning bolt", CEL and a P2122 DTC code stored.

If I shut the truck off and re-start it it runs normally again. Then some time later (in this recent case it was 3 months) it happens again.

I took it to the dealer the last time this happened, with DTC stored and CEL still on, but it did no good - they couldn't find anything wrong and just cleared the code.

I don't want to put in a new $$$ computer in unless I'm sure that's the problem.

The problem you described with your truck seems like it could have been a power problem - like it took time for the PCM to "wake up" every time. In my case it seems to be throwing an erroneous code at random.