Lost 4WD After Trailer Use!

[GM94]

Hey all!

I'm new here (just joined the forum, had my first and only RAM since March of last year), and have searched everywhere for a solution to this. 2019 RAM 1500 Bighorn 5.7, ~94k miles. Apologies for length of post; I don't want to leave something out that may be hiding the answer.

I used a trailer from a friend of my dad's to move between houses. I have used it before with no issue, but the wiring was admittedly pretty torched toward the 4-pin horizontal connector. First trip went great, but had a rough start before heading back for round 2. Leaving old house on second trip, and the truck wont start. Battery is drained. Pulled the manual neutral to get on a level surface and was jump-started by a buddy (ALWAYS HAVE JUMPERS ON YOU). Disconnected the trailer overnight. Went to return it the next day and, when I went to put the connector in, I noticed one of the 3 male pins was MISSING. Looked in the receptacle and there it was, lodged in. Returned the trailer without plugging it back in, and removed the broken pin. Truck operating normally. I checked with OBD2 scanner (BlueDriver), and showed code P1DF3 - ECU not initialized. THIS WAS THE ONLY CODE I HAD AT THE TIME.

The next week, we got about 3-4" of snow. Went to shift into 4WD, and it failed to do so. I noticed that I don't have a SERV4WD light on my dash off of a hard start, but I DO get one flashed when I get in after a remote start and push the button. Ran the scanner again, and had a slew of codes. My codes are in the file attached for the sake of the size of this post. I solved the initialization code by disconnecting the negative lead from the battery, and connecting it to the positive while still attached (electrician by trade, so I have also been looking at wiring as I go). Ignore the TPMS codes, I have yet to replace them. The one that really perplexed me was the C10CA - ITBM Adjustment Switch : Short to Ground code, until I realized that the 4-pin and 7-pin shared a wiring harness.

Steps I have taken:
- Replaced the battery (was 5 years old anyway)
- Located and checked fuses related to issues (ECU, TCCM, etc.)
- I will note that all fuses I pulled were NOT blown, but did show heat marks. I replaced them anyway.
- Checked battery output while running (sitting at ~15V)


I can only find posts about parts of my overall problem, and most were fixed by either flashing the ECM, finding loose or broken wires at the actuator, or replacing parts until its fixed. I also read something about plugging a trailer with a confirmed good 4-pin connector in and seeing if lights would come on. I would like to get as much input as I can before making any further moves.

Any and all help would be amazing! Thank you!

 

[kapinallinen2]

Hey all!

I'm new here (just joined the forum, had my first and only RAM since March of last year), and have searched everywhere for a solution to this. 2019 RAM 1500 Bighorn 5.7, ~94k miles. Apologies for length of post; I don't want to leave something out that may be hiding the answer.

I used a trailer from a friend of my dad's to move between houses. I have used it before with no issue, but the wiring was admittedly pretty torched toward the 4-pin horizontal connector. First trip went great, but had a rough start before heading back for round 2. Leaving old house on second trip, and the truck wont start. Battery is drained. Pulled the manual neutral to get on a level surface and was jump-started by a buddy (ALWAYS HAVE JUMPERS ON YOU). Disconnected the trailer overnight. Went to return it the next day and, when I went to put the connector in, I noticed one of the 3 male pins was MISSING. Looked in the receptacle and there it was, lodged in. Returned the trailer without plugging it back in, and removed the broken pin. Truck operating normally. I checked with OBD2 scanner (BlueDriver), and showed code P1DF3 - ECU not initialized. THIS WAS THE ONLY CODE I HAD AT THE TIME.

The next week, we got about 3-4" of snow. Went to shift into 4WD, and it failed to do so. I noticed that I don't have a SERV4WD light on my dash off of a hard start, but I DO get one flashed when I get in after a remote start and push the button. Ran the scanner again, and had a slew of codes. My codes are in the file attached for the sake of the size of this post. I solved the initialization code by disconnecting the negative lead from the battery, and connecting it to the positive while still attached (electrician by trade, so I have also been looking at wiring as I go). Ignore the TPMS codes, I have yet to replace them. The one that really perplexed me was the C10CA - ITBM Adjustment Switch : Short to Ground code, until I realized that the 4-pin and 7-pin shared a wiring harness.

Steps I have taken:
- Replaced the battery (was 5 years old anyway)
- Located and checked fuses related to issues (ECU, TCCM, etc.)
- I will note that all fuses I pulled were NOT blown, but did show heat marks. I replaced them anyway.
- Checked battery output while running (sitting at ~15V)


I can only find posts about parts of my overall problem, and most were fixed by either flashing the ECM, finding loose or broken wires at the actuator, or replacing parts until its fixed. I also read something about plugging a trailer with a confirmed good 4-pin connector in and seeing if lights would come on. I would like to get as much input as I can before making any further moves.

Any and all help would be amazing! Thank you!

I would recommend subscribing to Alldatadiy, it has the troubleshooting procedure for that DTC.
Single Vehicle Subscription | ALLDATA

C10CA-11 ITBM ADJUSTMENT SWITCH - CIRCUIT SHORT TO GROUND​

For a complete TRAILER TOW SYSTEM wiring diagram, (refer to the Wiring Information) .

Theory of Operation​

NOTE: The Integrated Trailer Brake Module (ITBM) Pulse Width Modulating (PWM) output is present if a trailer is connected or not connected.
The Integrated Trailer Brake Module (ITBM) communicates with the vehicle through the high speed CAN C bus. The ITBM monitors the Brake Pedal Status, Vehicle Speed and Electronic Stability Control (ESC) status via CAN message. It also outputs the Trailer Status, Gain Setting, and Trailer Brake Output Power to the vehicle. The ITBM connects to the electric trailer brakes through the 7-Way connector and controls the brake force through a Pulse Width Modulating (PWM) duty cycle. The ITBM PWM duty cycle output is present continuously.
The ITBM controls the PWM output to the trailer brakes in three ways. The first occurs while the brake pedal becomes active and vehicle speed is greater than 0 km/h (0 mph). The second is the manual lever on the ITBM that can be controlled by the driver. If both the manual lever and the brake pedal are active simultaneously, the greater of the two, in terms of PWM output, will prevail. The third is that it will become active during an ESC trailer sway event.

When Monitored and Set Conditions​

When Monitored: This diagnostic runs continuously when the following conditions are met:

• Continuously.
• No under voltage DTCs.
• Trailer or trailer simulator connected to the vehicle’s Trailer Tow harness connector.

Set Conditions:

• Integrated Trailer Brake Module (ITBM) is sensing a short on the Tow Brake Switch Decrease or Increase circuits.

Default Actions:

• Automatic braking and manual lever braking (squeeze switch) disabled.
• Malfunction Indicator Lamp (MIL) lamp illuminated.
• Electronic Vehicle Instrument Center (EVIC) displays "Service Trailer Brakes".

​

Possible Causes​

MANUAL TRAILER LEVER BRAKING (SQUEEZE SWITCH)

VEHICLE TRAILER TOW WIRING/CONNECTOR

TRAILER TOW BRAKE SWITCH DECREASE CIRCUIT SHORTED TO GROUND

TRAILER TOW BRAKE SWITCH INCREASE CIRCUIT SHORTED TO GROUND

INTEGRATED TRAILER BRAKE MODULE (ITBM)

Always perform the PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE before proceeding. (Refer to 28 - DTC-Based Diagnostics/Standard Procedure).