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2020 RAM 3500 check engine light, codes P1E1C and U040F. Any tips on what to look at first?

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LBC_Jeff

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Hi everyone. I have a 2020 RAM 3500 Laramie with a 6.7 diesel. the check engine light came on a few days ago and when I check the codes it came up with those two. I cleared the codes and they came back. Have any of you had these codes and if so, how did you resolve?

in looking at google searches it looks like it could be the DEF dosing control unit or wiring that goes to it, maybe? Any idea where the DEF dosing control unit is and how to test it to see if it's the issue?

thanks,

jeff in long beach.

from google searches:
Code: P1E1C
Definition: Reductant System Wake Up Circuit High
Description: The Diesel Exhaust Fluid (DEF) Dosing Control Unit is used to control the operation and monitoring of the Diesel Exhaust Fluid system. The DEF Dosing Control Unit is the central control for the aftertreatment diesel exhaust fluid dosing system, and handles the tank level sensing, tank temperature sensing, line heating, and tank heating. The DEF Dosing Control Unit shares information with the Powertrain Control Module (PCM) over the J1939 Data Link. The PCM will illuminate the MIL light after the diagnostics runs and fails for two consecutive trips. The PCM will turn off the MIL light when the monitor runs and passes in three consecutive key cycles.
Cause:
  • DCU WAKE UP SIGNAL SHORTED TO VOLTAGE
  • DCU WAKE UP SIGNAL OPEN/HIGH RESISTANCE
  • DEF DOSING CONTROL UNIT

Code: U040F
Definition: Invalid Data Received From Reductant Control Module
Description: The Diesel Exhaust Fluid (DEF) Dosing Control Unit is used to control the operation and monitoring of the Diesel Exhaust Fluid system. The DEF Dosing Control Unit is the central control for the aftertreatment diesel exhaust fluid dosing system, and handles the tank level sensing, tank temperature sensing, line heating, and tank heating. The DEF Dosing Control Unit shares information with the Powertrain Control Module (PCM) over the J1939 Data Link. The PCM will illuminate the MIL light after the diagnostics runs and fails for two consecutive trips. The PCM will turn off the MIL light when the monitor runs and passes in three consecutive key cycles.

Cause:
  • DEF DOSING CONTROL UNIT CONNECTOR CORROSION OR FOREIGN MATERIAL
  • INCORRECT J1939 DATALINK TERMINATION RESISTANCE
  • DEF DOSING CONTROL UNIT
  • POWERTRAIN CONTROL MODULE (PCM)
 
The dosing control unit is mounted on top of the DEF tank. It has two wire harnesses going to it. The DCU wake-up circuit is on pin 4 of the smaller connector. You could separate the connector, inspect for pushed back or dirty pins, check for battery voltage on the pin. If you see no issues and you have voltage you could clear the code and try again, or if you have no way to clear the code it takes three drive cycles to clear if all is ok again.
Sometimes simply disconnecting and reconnecting the plug will clear the bad connection and it will work again. If that's the case, get some contact cleaner and thoroughly clean the connection.
 
PRS said:
The dosing control unit is mounted on top of the DEF tank. It has two wire harnesses going to it. The DCU wake-up circuit is on pin 4 of the smaller connector. You could separate the connector, inspect for pushed back or dirty pins, check for battery voltage on the pin. If you see no issues and you have voltage you could clear the code and try again, or if you have no way to clear the code it takes three drive cycles to clear if all is ok again.
Sometimes simply disconnecting and reconnecting the plug will clear the bad connection and it will work again. If that's the case, get some contact cleaner and thoroughly clean the connection.
Click to expand...
thanks for the info!! I'll try that when it stops raining!

jeff in long beach.
 
@PRS's explanation is why I keep coming to the hdrams forums. His knowledge and willingness to share it is invaluable.
 

P1E1C code just came on today after working in the storm all day yesterday here in North Carolina. Cleared it out came back on 3 ignition cycles later. 2022 Ram 2500 6.7 31,000 miles first problem so far. What did you get figured out on yours? Any help is greatly appreciated.​

 
LBC_Jeff said:
Hi everyone. I have a 2020 RAM 3500 Laramie with a 6.7 diesel. the check engine light came on a few days ago and when I check the codes it came up with those two. I cleared the codes and they came back. Have any of you had these codes and if so, how did you resolve?

in looking at google searches it looks like it could be the DEF dosing control unit or wiring that goes to it, maybe? Any idea where the DEF dosing control unit is and how to test it to see if it's the issue?

thanks,

jeff in long beach.

from google searches:
Code: P1E1C
Definition: Reductant System Wake Up Circuit High
Description: The Diesel Exhaust Fluid (DEF) Dosing Control Unit is used to control the operation and monitoring of the Diesel Exhaust Fluid system. The DEF Dosing Control Unit is the central control for the aftertreatment diesel exhaust fluid dosing system, and handles the tank level sensing, tank temperature sensing, line heating, and tank heating. The DEF Dosing Control Unit shares information with the Powertrain Control Module (PCM) over the J1939 Data Link. The PCM will illuminate the MIL light after the diagnostics runs and fails for two consecutive trips. The PCM will turn off the MIL light when the monitor runs and passes in three consecutive key cycles.
Cause:
  • DCU WAKE UP SIGNAL SHORTED TO VOLTAGE
  • DCU WAKE UP SIGNAL OPEN/HIGH RESISTANCE
  • DEF DOSING CONTROL UNIT

Code: U040F
Definition: Invalid Data Received From Reductant Control Module
Description: The Diesel Exhaust Fluid (DEF) Dosing Control Unit is used to control the operation and monitoring of the Diesel Exhaust Fluid system. The DEF Dosing Control Unit is the central control for the aftertreatment diesel exhaust fluid dosing system, and handles the tank level sensing, tank temperature sensing, line heating, and tank heating. The DEF Dosing Control Unit shares information with the Powertrain Control Module (PCM) over the J1939 Data Link. The PCM will illuminate the MIL light after the diagnostics runs and fails for two consecutive trips. The PCM will turn off the MIL light when the monitor runs and passes in three consecutive key cycles.

Cause:
  • DEF DOSING CONTROL UNIT CONNECTOR CORROSION OR FOREIGN MATERIAL
  • INCORRECT J1939 DATALINK TERMINATION RESISTANCE
  • DEF DOSING CONTROL UNIT
  • POWERTRAIN CONTROL MODULE (PCM)
Click to expand...

P1E1C code just came on today after working in the storm all day yesterday here in North Carolina. Cleared it out came back on 3 ignition cycles later. 2022 Ram 2500 6.7 31,000 miles first problem so far. What did you get figured out on yours? Any help is greatly appreciated.​

 
provencio333 said:

P1E1C code just came on today after working in the storm all day yesterday here in North Carolina. Cleared it out came back on 3 ignition cycles later. 2022 Ram 2500 6.7 31,000 miles first problem so far. What did you get figured out on yours? Any help is greatly appreciated.​

Click to expand...
Sorry, I’m no help….i was about to try to figure it out when i check engine light went off and hasn’t came back on…..yet

Jeff
 
LBC_Jeff said:
Sorry, I’m no help….i was about to try to figure it out when i check engine light went off and hasn’t came back on…..yet

Jeff
Click to expand...
Thanks! If i have to do anything Ill let you know Im going to try what that gentlemen told you to try.
 
Well this is what was found. The connector going to the Diesel Exhaust Fluid Dosing Control Unit had a burned pin causing the code P1E1C. Fix is new connector and module. The kick is can't get for at least 45 days from the dealer.
Part#68305247AA-Pigtail
Part#68458603AA-Module

UPDATE- After driving 375 miles in a rental car 2 different dealership in Atlanta, Georgia and Lexington South Carolina I have parts in hand will get fixed now. Does anyone know if Ram will reimburse since i am still under warranty?
 
Last edited:
Everything went well. The module had to be programed but the the truck is back to work again. Not sure how the corrosion built up on such a new truck. I want to find a way to protect it for the future.
 
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