P2764 on 2014-2020 Ram 3500: Torque Converter Solenoid Circuit Low Causes and Fixes

What's Unique About the 2014-2020 Ram 3500

It is critical to identify which transmission your Ram 3500 has, as the causes and parts differ significantly. Trucks with the standard-output 6.7L Cummins use the Chrysler 68RFE, while trucks with the High-Output (H.O.) engine use the Aisin AS69RC. The initial TSB #9004009 mentioned in pass 1 for the 62TE transmission is not applicable to either of these heavy-duty units. For the 68RFE, the TCC solenoid is integrated into a large, replaceable solenoid block. For the Aisin AS69RC, while torque converter failure is a known weakness (as evidenced by related TSBs), the solenoids are individually replaceable, though often serviced with the valve body. Internal wiring harnesses on the Aisin are also known to become brittle from heat cycles, which can cause a circuit low fault.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: The 2014-2020 range covers the end of the fourth generation (2014-2018) and the start of the fifth generation (2019-2020). Fourth-gen models typically use the 68RFE or Aisin AS69RC for diesel engines. Fifth-gen models continued with these options but introduced a new solenoid pack design for the 68RFE in 2019. The diagnostic principles remain similar across generations, but using the correct year-specific parts is critical.

Symptoms You May Notice

• Check Engine Light is on
• Transmission slipping or shuddering, especially during moderate acceleration when lock-up should occur
• Vehicle stalling when coming to a stop
• Harsh or erratic shifting
• Engine RPMs are higher than usual at highway speeds
• Decreased fuel economy
• Transmission may enter 'limp mode', limiting speed and gear selection

Most Likely Causes

1. Faulty Transmission Solenoid Pack (68RFE) or TCC Solenoid (Aisin) 🔴 High Probability → Shop Transmission Valve Body The solenoid is an electromechanical part that wears out. On the 68RFE, it's part of a large block mounted to the valve body that is a common failure point. On the Aisin, individual solenoids or their internal wiring can fail.
   How to confirm: A technician can use a scan tool to command the solenoid on/off while monitoring voltage. The solenoid's internal resistance can also be tested with a multimeter and compared to specs. For the Aisin AS69RC, the TCC/SLU solenoid should measure 4-6 ohms. For the 68RFE, most solenoids are around 1.3 ohms, but the pressure control solenoid is 4.9 ohms.
   Typical fix: For the 68RFE, replace the entire solenoid pack. 🎬 Watch: Step-by-step guide to replacing the 68RFE solenoid block. For the Aisin AS69RC, replace the individual TCC/SLU solenoid, which often requires dropping the valve body. 🎬 See this trick for removing stuck Aisin AS69RC solenoids.
   Est. part cost: $250-$600
2. Wiring or Connector Issue 🟡 Medium Probability The external transmission harness is exposed to heat and debris. On the Aisin AS69RC specifically, the internal wiring harness is known to become brittle and crack or break near the solenoid connectors, causing an open or short circuit.
   How to confirm: Visually inspect the external harness. For an internal issue, the pan must be dropped. Test for continuity and shorts in the TCC solenoid circuit from the TCM connector to the transmission connector.
   Typical fix: Repair the damaged section of the external harness or replace the internal transmission harness.
   Est. part cost: $50-$300
3. Failing Torque Converter 🟡 Medium Probability → Shop Automatic Transmission Torque Converter Heavy towing and high torque from the Cummins engine put immense stress on the torque converter's lock-up clutch. Debris from a failing clutch can contaminate the fluid and damage solenoids, while internal mechanical failure (like a dislodged K1 snap ring on some Aisin models) can directly cause TCC circuit codes.
   How to confirm: This is diagnosed after confirming the solenoid and wiring are good. A noticeable shudder during lock-up, excessive metallic debris in the transmission pan, or out-of-spec Clutch Volume Index (CVI) readings on a scan tool all point to converter failure.
   Typical fix: Replace the torque converter. This is a major repair that requires removing the transmission. Many owners opt for a heavy-duty billet aftermarket converter. 🎬 Watch: How to remove the transmission and replace the torque converter.
   Est. part cost: $400-$1200
4. Low or Dirty Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly While unlikely to directly cause a 'low circuit' code, fluid contaminated with clutch material or metal shavings can cause the TCC solenoid's plunger to stick or operate erratically, leading to performance issues that may trigger a fault.
   How to confirm: Check the transmission fluid level and condition. Fluid should be at the correct level and red/pink, not brown, black, or smelling burnt. Inspect for excessive metal particles.
   Typical fix: Perform a transmission fluid and filter change. If significant debris is found, further diagnosis is required.
   Est. part cost: $100-$250

Rare But Worth Checking

• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly A faulty TCM is rare but possible. The module's internal driver for the TCC circuit can fail. This should only be considered after all other possibilities, including wiring, solenoids, and mechanical components, have been exhaustively tested and ruled out.

Diagnosis Steps

1. Check and verify the transmission fluid level and condition. Look for a burnt smell or metallic particles.
2. Use an advanced OBD-II scanner to check for any other transmission-related codes and view live data.
3. Monitor the live data for the TCC solenoid, observing its commanded state versus its actual state and the circuit voltage.
4. Monitor the Clutch Volume Index (CVI) values. Out-of-spec values can indicate internal hydraulic leaks or worn clutches, pointing towards a mechanical rather than purely electrical issue.
5. Perform a thorough visual inspection of the transmission's external wiring harness and connectors for any signs of damage, corrosion, or loose connections.
6. If the external wiring is good, perform a resistance test of the TCC solenoid circuit. This can be done at the transmission case connector or from the TCM connector to isolate the issue to the external harness, internal harness, or solenoid itself.
7. If the solenoid and wiring test good, the problem is likely mechanical. Drop the transmission pan and inspect for excessive clutch material or metal shavings, which strongly indicate a failing torque converter or other internal damage.

Parts You'll Likely Need

• Transmission Solenoid Pack (68RFE) (OEM #68376695AA (Pre-2019, check connector color) or 68456067AA (2019+)) — This is the most likely electrical component to fail for this code on 68RFE-equipped trucks. The TCC solenoid is integrated and not serviced separately. It is critical to match the part number and connector color (white or grey) to your vehicle's year.
  Trusted brands: Mopar, Rostra, RevMax
  OEM price range: $400-$600
  Aftermarket price range: $250-$450
• Torque Converter — If the solenoid and wiring are good, internal failure of the torque converter is the next most likely cause, especially on high-mileage or hard-working trucks. This is a known issue on the Aisin AS69RC.
  Trusted brands: Mopar, LuK, SunCoast, RevMax
  OEM price range: $600-$1000
  Aftermarket price range: $500-$1500 (Billet/HD)
• TCC Solenoid (Aisin AS69RC) — On the Aisin transmission, the TCC lock-up solenoid (often called SLU solenoid) can be replaced individually, but can be difficult to source and is often replaced with the valve body.
  Trusted brands: Aisin (OEM)
  OEM price range: $150-$300 (solenoid only)
  Aftermarket price range: $100-$200
• Transmission Fluid — Fluid must be replaced any time the transmission pan is dropped. Use only Mopar ATF+4 for the 68RFE.

Related Codes That Often Appear With This One

• P0740 — This code indicates a general 'Torque Converter Clutch Circuit Malfunction' and is often set alongside the more specific P2764 when the TCC system has a problem.
• P0700 — This is a generic code from the Engine Control Module (ECM) indicating that the Transmission Control Module (TCM) has stored a fault code. It serves as a general alert that a transmission-specific code like P2764 is present.

Technical Service Bulletins (TSBs) & Recalls

• 21-027-16: While for code P2757, this TSB shows a precedent for torque converter failure related to the TCC circuit on 2016 Ram 3500 models with the Aisin AS69RC transmission.

Platform-Specific Known Issues

• TSB 21-027-16 Rev. A: Torque Converter Failure on Aisin AS69RC: → Shop Automatic Transmission Torque Converter For some 2016 Ram 3500 models with the Aisin AS69RC built between March 29, 2016, and April 11, 2016, a related code (P2757 - TCC Circuit Performance) is caused by a dislodged snap ring inside the torque converter. The official fix is to replace the torque converter. While for a different code, this establishes a clear history of TCC-related mechanical torque converter failures on this platform.
• 68RFE Solenoid Pack Connector Color: When replacing the solenoid pack on a 68RFE transmission, it is crucial to verify the color of the main electrical connector (typically white or grey) on the old unit. Installing a pack with the wrong connector color can lead to communication faults or failure to operate.
• Aisin AS69RC Internal Wiring Harness Failure: A known issue on the Aisin transmission is the internal wiring harness becoming brittle and failing due to heat. The wires can crack or break at the solenoid connectors, causing an open or short circuit that will log a P2764 code. This requires dropping the pan and valve body to inspect and replace the harness.

Mechanic-Grade Diagnostic Values

• Aisin AS69RC TCC/SLU Solenoid Resistance — expected: 4-6 Ohms. Failure: A reading of 0 Ohms (short) or infinite Ohms (open circuit).
• 68RFE TCC Solenoid Circuit Resistance (at TCM connector) — expected: Approximately 1.8 Ohms. Failure: An open circuit (no continuity) or significantly higher/lower resistance.
• 68RFE Solenoid Pack (individual solenoids) — expected: Most solenoids are 1.3 Ohms; the Pressure Control solenoid is 4.9 Ohms.. Failure: Readings outside of these specifications.
• TCC Solenoid Circuit Voltage (Key On) — expected: Approximately 12 V (+/- 0.5V). Failure: Voltage below 9V indicates a low-voltage condition requiring investigation of the power supply or wiring.
• 68RFE Clutch Volume Index (CVI) — expected: Varies by clutch pack (e.g., 4C CVI should be above 5). Values are learned by the TCM.. Failure: Near-zero or out-of-range CVI values can indicate a mechanical or hydraulic failure (worn clutches, leaks) rather than an electrical one.

Scan Tool Commands That Help

• wiTECH (or capable aftermarket scanner): TCC Solenoid Activation / Duty Cycle Command — This bidirectional control is used to command the TCC solenoid on and off while monitoring circuit voltage. It directly tests the solenoid's electrical function and the integrity of the control circuit from the TCM. If the solenoid clicks and voltage responds as commanded, the electrical circuit is likely good, pointing towards a mechanical or hydraulic issue.
• wiTECH (or capable aftermarket scanner): Quick Learn / Adaptive Learning Reset — This procedure is required after replacing the transmission, solenoid pack, or valve body. It resets and relearns the Clutch Volume Index (CVI) values to ensure proper shift quality and prevent harsh engagement.

Wiring & Ground Locations

• 68RFE TCM C4 Connector — The C4 connector is one of two main connectors at the Transmission Control Module (TCM).. For testing the L/R solenoid circuit (related to P0750 but demonstrates the method), a technician would check resistance between the pin in the harness that goes to pin 2 at the transmission and the pin that goes to pin 10 at the transmission. This same method applies to testing the TCC circuit by identifying its specific pins.
• Transmission Main Ground Strap — A braided ground strap typically connects the transmission case to the vehicle's chassis or frame, often near a transmission mount.. A poor or missing ground can cause inconsistent voltage and corrupted data signals for all transmission sensors and solenoids, potentially triggering a P2764 code. Verifying this ground is secure and free of corrosion is a critical early step.

Real Owner Repair Stories

• DodgeForum.com user (2015 Dodge Ram 3500 with 6.7L Cummins and Aisin transmission) — While pulling a fifth wheel up a mountain, the truck shuttered, lost power, the check engine light came on, and it could not be driven over 10 mph.
  ❌ Tried (didn't work) The dealer replaced the valve body and the internal wiring harness in the Aisin transmission.
  ✅ What actually fixed it The issue persisted after the initial repair. The dealer then diagnosed a bad torque converter, which was the presumed final fix (though the user did not post a final confirmation after the converter replacement). This story highlights a common misdiagnosis where electrical components are replaced when the root cause is a mechanical torque converter failure.

OEM Part Supersession History

• 68376695AA → 68376695AB — Standard part revision and improvement.
  Heads up: This is the 'grey connector' solenoid pack for pre-2019 68RFE transmissions. It is not compatible with 2019+ models.
• 68456067AA → 68456067AB — Standard part revision and improvement.
  Heads up: This is the 'blue connector' solenoid pack for 2019+ 68RFE transmissions, which use an auxiliary valve body. It is not backward compatible with pre-2019 models.

Model Year Variations Within This Range

• 2019+: For the 68RFE transmission, 2019 and newer models feature an auxiliary valve body which includes a new, dedicated TCC solenoid. The main solenoid body was changed to a 'blue connector' style and is not interchangeable with the 'grey connector' style from pre-2019 models. This change requires programming the new solenoid's flow-rate into the PCM if replaced.