2012 Ram 3500 engine problems: check engine light on

Check Engine Light On

2012 Ram 3500

This problem may be covered under warranty. Ask your Ram dealer.


pretty bad
Typical Repair Cost:
No data
Average Mileage:
14,951 miles
Total Complaints:
7 complaints

Most Common Solutions:

  1. not sure (7 reports)
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2012 Ram 3500 engine problems

engine problem

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2012 Ram 3500 Owner Comments

problem #7

Sep 012014

3500 SLT 6.7L Diesel

  • Automatic transmission
  • 29,204 miles


Bought this 2012 RAM3500 used in Feb. 2014. Drove it for couple of months, then the engine light came on. Error code came up as P014C with OBD diagnostic tool - (O2 Sensor 1/1 Slow Response - Rich To Lean).

Took it on an hour long highway trip and on the way back topped it up with diesel - Low and behold the light goes away. A few weeks later, the engine light came back on again. Took truck for oil change as it was due anyways and surprisingly after the oil change the light goes away again for some reason. Now the engine light is back on again (same code) and for many weeks now and it will not go away, even with diesel additives and 3 hour long highway trips. Called selling dealer and they said it could be bad diesel. Will wait for tank to go nearly empty and will refilled it with different brand diesel and see.

Seems like this is a common problem for this truck from what I read online. I used to have a 2000 RAM2500 and it runs like a charm. The mileage on my 2012 RAM3500 has only less than 48,000 km on it. Don't they have a fix for it by now, seriously!!

- , Victoria, BC, Canada

problem #6

Sep 112013

3500 ST 6.7L Diesel

  • Automatic transmission
  • 14,000 miles

O2 sensor and harness malfunction, three trips to dealer (no loaner vehicle) FINALLY "repaired" I was told by the service manager they had a TSB (they discovered this after three trips)?

Problem reoccurs a year later, truck runs ok, so screw the light. Then on July 4 2014, while on a vacation trip with family, truck goes into "limp home" mode. I took out my trusty OSBDII code reader, cleared the codes and truck started running again. BTW, no dealers working on the fourth...

Call to selling dealer and RAM Customer Service, no help. Call to Cummins, no GD help!

So, my "Henco En Mexico" "merican truck is a POS and the butt heads who sold me this $50K boat anchor are laughing all the way to the bank (financed with my tax-payer money).

RAM sucks a big green tamale!

- , Elkhorn City, KY, USA

problem #5

Jul 172012

3500 Bighorn 6.7L

  • Automatic transmission
  • 450 miles

This was to me the start of my issues. I bought this truck new in July of 2012 and had numerous problems immediately. None of which have ever been resolved

- , Lakewood, CO, USA

problem #4

Aug 052013

3500 Laramine 6.7L Diesel

  • Automatic transmission
  • 16,000 miles


The check engine light goes on every 2 months or so with the codes related to the 02 sensor. It appears that Chrysler does not have a way to fix it.

- , Las Vegas, NV, USA

problem #3

May 152013

3500 Laramine 6.7L Diesel

  • Automatic transmission
  • 13,000 miles

Check engine light comes on every 2 months or so. Code is always related to the 02 sensor and it does not appear Chrysler has a way to fix this as it keeps happening. I get lip service from Chrysler for the most part and at this point the truck qualifies under the lemon law. Seems to happen when I have a trip planned or need it to tow the trailer - which is why I bought it. The truck is pretty much dysfunctional.

- , Las Vegas, NV, USA

problem #2

Oct 102013

3500 Laramine 6.7L Diesel

  • Automatic transmission
  • 17,000 miles

The check engine light goes on with the codes related to the 02 sensor. This happens every 2 months or so and Chrysler does not appear to be able to fix it.

- , Las Vegas, NV, USA

problem #1

Jan 182013

3500 6.7L Cummings

  • Automatic transmission
  • 15,000 miles

This is the 3rd time in the last 8 months last time the harness and o2 sensor had to be replaced. Real bad fuel mileage as well.

- , Albuquerque, NM, USA

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