P0841 on 2024 Ram 3500: Transmission Pressure Sensor Circuit Causes and Fixes

What's Unique About the 2024-2024 Ram 3500

For modern Ram Heavy Duty trucks, this code is often associated with the sophisticated multi-speed automatic transmissions they employ (like the 68RFE or Aisin AS69RC). These transmissions rely on precise hydraulic control, making them sensitive to fluid condition and pressure. Critically, for 2024 Ram 2500/3500 models with the 68RFE transmission built between June 14, 2024, and September 04, 2024, Technical Service Bulletin (TSB) 21-012-25 REV. E identifies that P0841 (among other codes) can be caused by a cracking rear selective thrust bearing. In this specific scenario, the manufacturer's mandated repair is a complete transmission replacement, elevating the severity of this code significantly for affected vehicles.

Diagnostic Flowchart

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

Symptoms You May Notice

• Check Engine Light or Transmission Warning Light is on.
• Harsh, erratic, or delayed shifting.
• Transmission slipping between gears.
• Vehicle enters 'limp mode' (stuck in one gear).
• Reduced fuel economy.
• Inability to shift into certain gears.
• Vehicle stalls when slowing to a stop.

Most Likely Causes

1. Low, dirty, or incorrect transmission fluid 🔴 High Probability → Shop Transmission Assembly Transmissions in heavy-duty trucks work hard, leading to fluid breakdown over time. Incorrect fluid levels directly impact hydraulic pressure, which can cause the sensor readings to be out of range.
   How to confirm: Check the transmission fluid level and condition according to the manufacturer's procedure. On many newer trucks, this must be done by a technician as there is no dipstick. The fluid should be clean, red, and not have a burnt smell. Low fluid can cause a loss of prime, which may set other codes like P0944.
   Typical fix: Perform a transmission fluid and filter change using the correct Mopar ATF+4 or equivalent fluid.
   Est. part cost: $100-$250
2. Faulty Transmission Fluid Pressure Sensor/Switch 🟡 Medium Probability → Shop Transmission Assembly The sensor is an electronic component that can fail over time due to heat and vibration. Aftermarket sensors are noted by some specialists to be prone to failure and inaccurate readings.
   How to confirm: A technician can monitor the sensor's voltage output using a professional scan tool to see if it's providing erratic or out-of-range readings. The sensor and its circuit can also be tested with a multimeter. The sensor is located inside the transmission on the valve body.
   Typical fix: Replace the faulty transmission fluid pressure sensor. This sensor is often located on the valve body inside the transmission pan. Using an OEM Mopar part is highly recommended.
   Est. part cost: $50-$150
3. Wiring or Connector Issues 🟡 Medium Probability The wiring harness leading to the transmission is exposed to road debris, moisture, and heat, which can cause corrosion or damage. A common failure point is the main connector on the transmission case, which can get filled with corrosion.
   How to confirm: Visually inspect the wiring harness and connector going to the transmission for any signs of damage, corrosion (green crust), or loose connections. A multimeter can be used to check for continuity and shorts in the circuit. Wiggling the wires while monitoring live data can reveal intermittent faults. 🎬 Watch: How to diagnose common 68RFE transmission problems
   Typical fix: Repair the damaged section of the wiring harness or thoroughly clean (using contact cleaner and a small brush) and reseal the corroded connector with dielectric grease.
   Est. part cost: $20-$100
4. Internal Valve Body Issue ⚪ Low Probability → Shop Transmission Valve Body Debris from normal wear or a botched fluid flush can cause valves or solenoids within the valve body to stick or fail. Cross-leaks within the valve body are a known issue on the 68RFE that can cause pressure rationality codes.
   How to confirm: This requires advanced diagnostics, often after ruling out fluid, sensor, and wiring issues. A technician may need to perform pressure tests or drop the transmission pan to inspect the valve body for debris or stuck valves. Incorrectly placed check balls during a previous repair can also cause this code on newer models.
   Typical fix: Clean, repair, or replace the transmission valve body or solenoid pack.
   Est. part cost: $500-$1500

Rare But Worth Checking

• Cracked Rear Selective Thrust Bearing (68RFE Only): Extremely specific but critical. Per TSB 21-012-25 REV. E, this is the cause for P0841 and a host of other codes on 2024 Ram 2500/3500 trucks with the 68RFE transmission built between June 14, 2024, and September 04, 2024. This is a catastrophic internal failure. The only fix is a complete transmission replacement.
🎬 Watch: A step-by-step 68RFE transmission rebuild walkthrough
• Faulty Powertrain Control Module (PCM) or Transmission Control Module (TCM): → Shop Transmission Assembly This is very uncommon. The PCM/TCM should only be considered after all other possible causes (fluid, sensor, wiring, and internal mechanics) have been thoroughly ruled out.

Diagnosis Steps

1. Check the vehicle's build date (on the driver's side door jamb sticker). If it is between June 14, 2024, and September 04, 2024, and the truck has a 68RFE, immediately refer to TSB 21-012-25 REV. E as a transmission replacement may be required.
2. Check and verify the transmission fluid level and condition. Ensure the correct fluid type is being used.
3. Use a professional scan tool to check for any other related trouble codes, paying close attention to the cluster of codes mentioned in TSB 21-012-25 REV. E.
4. Inspect the transmission wiring harness and the main round connector on the transmission case 🎬 See how to repair a damaged transmission wiring harness for visible damage, corrosion (green crust), or loose pins.
5. With a scan tool, monitor the live data from the transmission fluid pressure sensor (TFP Voltage) while shifting through gears (P, R, N, D) and driving. Look for readings that are erratic, illogical, or do not change smoothly.
6. If the sensor signal is suspect, test the sensor's circuit for proper voltage, ground, and signal integrity using a digital multimeter, following the service manual procedure. Check for resistance above 5.0 ohms in the pressure switch sense circuit, which indicates an open.
7. If the sensor and wiring test good and the vehicle is not covered by the TSB, the problem likely lies within the transmission's valve body or other internal hydraulic circuits, requiring professional diagnosis.

Parts You'll Likely Need

• Transmission Fluid Pressure Sensor (OEM #4799758AF (For 68RFE Transmission)) — This sensor is a primary cause of the code when it fails electronically or provides incorrect readings. It is also referred to as a Line Pressure Sensor or Transducer.
  Trusted brands: Mopar, Standard Motor Products (SMP), Dorman
  OEM price range: $80-$150
  Aftermarket price range: $40-$90
• Transmission Fluid and Filter Kit — Low or dirty fluid is a very common cause. A fluid and filter service is a critical first step in diagnosis and a common solution.

Related Codes That Often Appear With This One

• P0868 — This code means 'Transmission Fluid Pressure Low' and often appears with P0841 because low system pressure can cause the pressure sensor's readings to be out of the expected range. TSB 21-012-25 REV. E lists them together as indicators of a potential thrust bearing failure.
• P0871 — This code relates to the 'Transmission Fluid Pressure Sensor/Switch 'C' Circuit' and can appear alongside P0841, indicating a more widespread hydraulic pressure sensing issue. TSB 21-012-25 REV. E also lists them together.
• P0731, P0732, P0733, P0734, P0735 — These codes for incorrect gear ratios are often a direct symptom of the hydraulic pressure problem that triggers P0841. The TSB lists these codes together as part of the same failure pattern.
• P0700 — This is a generic code indicating that the Transmission Control Module (TCM) has stored a fault. It acts as a 'check engine light' for the transmission and will almost always be present when a specific transmission code like P0841 is set.
• P0944 — This code for 'Loss of Hydraulic Pump Prime' is also listed in TSB 21-012-25 REV. E and points to the same severe internal failure (cracked thrust bearing) on affected 2024 models.

Technical Service Bulletins (TSBs) & Recalls

• 21-012-25 REV. E: Lists P0841-00 as a key indicator of a cracking rear selective thrust bearing in certain 2024 Ram 2500/3500 trucks with the 68RFE transmission, requiring a full transmission replacement.

Platform-Specific Known Issues

• NHTSA Technical Service Bulletin #21-012-25 REV. E is a critical document for this code on 2024 models. It applies to Ram 2500/3500 trucks with the 68RFE transmission built between June 14, 2024, and September 04, 2024. It states that a cluster of codes, including P0841, P0868, P0944, and multiple gear ratio errors, is caused by a 'cracking rear selective thrust bearing'. The bulletin instructs dealers not to attempt component repair; the only authorized fix is a complete transmission replacement.

Mechanic-Grade Diagnostic Values

• Transmission Fluid Pressure Sensor Voltage — expected: 0.5V - 4.5V. Failure: Readings outside this range, or readings that don't change with gear selection.
• Transmission Fluid Pressure Sensor Resistance — expected: 300-600Ω (per vehicle-specific manual). Failure: Resistance outside the specified range.
• Pressure Switch Sense Circuit Resistance (e.g., L/R circuit T50) — expected: Below 5.0 ohms. Failure: Resistance above 5.0 ohms indicates an open circuit.
• Pressure Switch Sense Circuit for Short to Ground — expected: High resistance (open circuit). Failure: Resistance below 5.0 ohms indicates a short to ground.

Scan Tool Commands That Help

• wiTECH (or equivalent professional scan tool): Quick Learn Procedure — After replacing the transmission, valve body, or solenoid pack, this procedure must be performed to allow the TCM to learn the new components' hydraulic characteristics and clutch fill volumes.
• wiTECH (or equivalent professional scan tool): TCM/ECM Reset — This should be performed after a new transmission is installed to clear old adaptive memory before starting the learn procedure.
• Miller tool #8333 (Transmission Simulator): Pressure Switch Test — This special tool is used to manually activate individual pressure switch circuits to isolate a fault between the wiring, the PCM, and the internal transmission solenoid/switch assembly.

Wiring & Ground Locations

• Transmission Solenoid/TRS Assembly Connector — On the left side of the 68RFE transmission case.. This is the main electrical interface for all internal solenoids and pressure switches, including the one that triggers P0841. It's a common point for corrosion and connection issues.
• Wiring Harness Chafe Point — Along the frame rail, particularly in the area near the driver's side mudflap.. The harness can rub against the frame, eventually causing an open or short in the pressure sensor circuit, which can set a P0841 code even if the sensor and transmission are good.
• Ground Straps — Multiple locations, including from the battery negative terminal to the body, near the windshield wiper motor, and on the engine block.. A poor ground connection for the PCM or TCM can cause erratic sensor readings and trigger false codes like P0841.

Real Owner Repair Stories

• Reddit user in r/Cummins (Ram with 68RFE, 112k miles, stock, frequent towing.) — Throws P0841, then has hard/late shifts and no overdrive. Clearing the code makes it shift normally for 10-15 miles before the code returns.
  ❌ Tried (didn't work) Replaced the transmission fluid pressure sensor., Replaced the entire valve body., Performed a transmission fluid flush and filter change.
  ✅ What actually fixed it The final cause was not posted by the original author, but a top-rated comment from another user suggested the cause was likely a wiring issue along the frame rail or a faulty PCM, as they had seen both cause this exact scenario.

OEM Part Supersession History

• 4799758 → 4799758AF — Part revision and improvement by the manufacturer.
  Heads up: Part number 4799758AF also supersedes 4799758AC and 4799758AD. Using the latest revision (AF) is recommended.

Model Year Variations Within This Range

• 2024 (build dates June 14 - Sept 04): Per TSB 21-012-25 REV. E, vehicles in this range with a 68RFE can experience a cracked rear selective thrust bearing, causing P0841 and other codes. The mandated fix is a complete transmission replacement, which is not the case for vehicles outside this build range.