P0712 on 2013 Ram 3500: Transmission Temperature Sensor Circuit Low Causes and Fixes

What's Unique About the 2013-2013 Ram 3500

For the 2013 Ram 3500, particularly those equipped with the common 68RFE automatic transmission, the transmission fluid temperature (TFT) sensor is not a small, standalone part. Instead, it is integrated into the main transmission solenoid pack (also called the solenoid block or valve body solenoid). This design means that a simple sensor failure often requires the replacement of the entire, more complex solenoid assembly, which resides inside the transmission oil pan.

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 is on
• Harsh, erratic, or delayed shifting
• Transmission may be stuck in one gear (limp mode)
• Transmission temperature warning light may be illuminated
• Improper torque converter clutch operation, potentially feeling like a slip or shudder
• Scan tool shows transmission temperature fixed at an extremely low value, such as -40°F or -38°C

Most Likely Causes

1. Failed Transmission Temperature Sensor / Solenoid Pack 🔴 High Probability The TFT sensor is part of the 68RFE solenoid pack, which is a known failure point over time due to heat and internal contaminants. The sensor itself can fail, creating the short circuit condition that triggers P0712. Failure of the sensor necessitates replacing the entire pack.
   How to confirm: Use a diagnostic scan tool to monitor the live data for the transmission fluid temperature. A reading that is stuck at an extremely low value (like -40°F) regardless of engine temperature 🎬 Watch: How to diagnose common 68RFE transmission issues points to a failed sensor or circuit. If wiring is confirmed good, the solenoid pack is the culprit.
   Typical fix: Replace the entire transmission solenoid pack. This also requires draining the fluid, removing the transmission pan, and replacing the filter. Some owners report that after replacement, the transmission control module (TCM) may need its adaptive memory reset with a capable scan tool to clear the limp mode condition.
   Est. part cost: $300-$500
2. Wiring Harness or Connector Issue 🟡 Medium Probability As a heavy-duty truck, the wiring harness leading to the transmission is exposed to harsh conditions, road debris, and potential corrosion, which can cause wires to short to ground. A user on Reddit suspected a wiring issue when their truck started reading the minimum temperature value intermittently.
   How to confirm: Visually inspect the wiring harness from the PCM to the transmission's main electrical connector. Look for any chafed, melted, or broken wires. Test the signal wire (often at terminal 8 of the transmission connector) for a short to ground using a digital multimeter. Check the main connector on the driver's side of the transmission for corrosion.
   Typical fix: Repair or replace the damaged section of the wiring harness. Clean or replace the corroded connector.
   Est. part cost: $20-$200

Rare But Worth Checking

• Powertrain Control Module (PCM) Fault: While uncommon, the PCM's internal circuit that reads the sensor can fail. This should only be considered after definitively ruling out the sensor and wiring as the cause. A PCM replacement is the last resort.

Diagnosis Steps

1. Connect an OBD-II scanner and confirm P0712 is the active code. Note any other transmission-related codes like P0711, P0713, or P0714.
2. Check for Technical Service Bulletins (TSBs). Several TSBs (e.g., 18-091-16, 18-018-13 REV. A) mention that a PCM software update can change the fault logic (e.g., from a one-trip to a two-trip fault) to prevent false codes. This should be an early step to rule out software glitches.
3. View the live data stream for the Transmission Fluid Temperature (TFT). If it shows a static, extremely low reading (e.g., -40°F), it strongly suggests a circuit or sensor fault.
4. Visually inspect the main transmission wiring harness and the connector at the transmission case for any signs of damage, corrosion, or loose pins.
5. If the wiring appears intact, disconnect the transmission harness and PCM connectors. Use a digital multimeter to test the TFT sensor signal wire (terminal 8 at the transmission connector) for a short to ground. Resistance to ground should be high (over 100 k/ohms).
6. If the wiring and connector are confirmed to be good, the failure is internal to the transmission, pointing to the solenoid pack/TFT sensor assembly.
7. If replacing the solenoid pack does not resolve the issue, the final step is to diagnose a potential fault within the Powertrain Control Module (PCM).

Parts You'll Likely Need

• Transmission Solenoid Pack (OEM #68456067AB) — The Transmission Fluid Temperature (TFT) sensor is integrated into this assembly on the 68RFE transmission. A sensor failure requires replacing the entire pack. The part number for 2013 models was likely the 'white connector' version, which has been superseded. The latest Mopar part number is 68456067AB, which replaces 68456067AA and 68367309AA.
  Trusted brands: Mopar, RevMax, Suncoast, ATS
  OEM price range: $380-$550
  Aftermarket price range: $300-$450
• Automatic Transmission Fluid (ATF+4) — The transmission fluid must be drained to access the solenoid pack. A typical drain and fill for a pan drop is 6-8 quarts, but if the valve body is removed and allowed to drain for an extended period, it could require up to 12 quarts.
  Trusted brands: Mopar, Valvoline, Castrol
  OEM price range: $10-$15 per quart
  Aftermarket price range: $7-$12 per quart
• Transmission Filter Kit (OEM #5013470AC) — The filters (spin-on and pan filter) should always be replaced whenever the transmission pan is removed.
  Trusted brands: Mopar, Wix, ATP
  OEM price range: $40-$60
  Aftermarket price range: $20-$40

Related Codes That Often Appear With This One

• P0711 — This code for 'Transmission Temperature Sensor Performance' often appears with P0712 as the sensor's readings are illogical, not just low. Multiple TSBs list these codes together.
• P0713 — This code for 'Transmission Temperature Sensor High' can appear intermittently with P0712 if the wiring has an intermittent short or open, causing the voltage to fluctuate wildly. TSBs also group these codes.
• P0714 — This code for 'Transmission Temperature Sensor Intermittent' is also frequently listed alongside P0712 in service bulletins, indicating an unstable circuit.

Technical Service Bulletins (TSBs) & Recalls

• 18-091-16: Mentions P0712 as a potential code that may be addressed by a PCM software update.
• 18-057-15 REV A: Also lists P0712 in the context of a PCM software flash.
• 18-030-14 REV. B: Includes P0712 in a list of DTCs that could be stored and potentially fixed via software updates.
• 18-018-13 REV. A: Explicitly states a software improvement was made to change P0712 from a one-trip fault to a two-trip fault to 'Prevent Or Reduce Unnecessary Malfunction Indicator Lamp (MIL) Illumination'.

Platform-Specific Known Issues

• The provided NHTSA Technical Service Bulletins (e.g., 18-091-16, 18-057-15 REV A) list P0712 among many other potential codes that can be resolved with a PCM software update. TSB 18-018-13 REV. A specifically notes that a software update was released to change the P0712 fault from a one-trip to a two-trip fault, reducing the chance of a MIL for intermittent issues. This highlights that checking for available PCM updates is a crucial diagnostic step to avoid unnecessary parts replacement for a software sensitivity issue.

Mechanic-Grade Diagnostic Values

• TFT Sensor Signal Voltage — expected: Approx. 0.5V (hot) to 4.5V (cold).. Failure: A reading near 0.0V, or specifically less than 0.16V for 5 seconds, indicates a short circuit and will set code P0712.
• TFT Sensor Resistance — expected: Resistance is high when cold and low when hot. A generic example is ~2.5 kΩ at 68°F (20°C).. Failure: An extremely low or near-zero resistance reading indicates a shorted sensor. A very high or open-circuit reading would typically set a P0713 code.

Scan Tool Commands That Help

• wiTECH (Dealer Scan Tool): Quick Learn — This procedure is required after replacing the transmission solenoid pack or valve body to reset and relearn clutch adaptive values. Failure to perform this can result in poor shift quality or failure to clear limp mode, even after the hardware is correctly replaced.

Wiring & Ground Locations

• Main Transmission Connector (23-way) — On the driver's side of the 68RFE transmission case, where the main vehicle harness connects to the solenoid pack.. This is the primary point for testing the circuit externally. Pin 23 is the Transmission Temperature Sensor Signal wire, and Pin 22 is the Sensor Ground. Testing for a short to ground on Pin 23 is a key diagnostic step.

Real Owner Repair Stories

• Turbo Diesel Register forum user 'Markhef05' (2008 Ram 2500 6.7L with 68RFE) — Initially had codes P0868 and P0871. After replacing parts, the truck went into limp mode (4th gear only) and set a P0750 (LR Solenoid Circuit fault).
  ❌ Tried (didn't work) Rebuilding the original solenoid pack., Installing a new, but ultimately faulty, 'rebuilt' solenoid pack which caused a P0750 code immediately.
  ✅ What actually fixed it The user discovered the 'rebuilt' solenoid pack they purchased was defective. Reinstalling their original, self-rebuilt solenoid pack (along with a new pressure sensor) resolved the immediate limp mode, though other shifting issues remained. This highlights the risk of defective aftermarket/rebuilt electronic components.
• Reddit user on r/Cummins (Ram with 68RFE transmission) — Intermittently enters limp mode, with the scan tool reading the transmission temperature as -38 degrees Celsius, a classic symptom of a shorted circuit.
  ❌ Tried (didn't work) The user was in the diagnostic phase.
  ✅ What actually fixed it The final fix was not posted by the original author, but the community correctly identified the cause as either a failed temperature sensor within the solenoid pack or a short in the wiring harness, which are the two primary causes for this specific symptom.

OEM Part Supersession History

• Gray Connector Solenoid Pack (for 2010+ models) → White Connector Solenoid Pack (originally for 2000-2009 models) — The white connector solenoid pack is often more available and is backward and forward compatible, servicing all 68RFE models from 2007.5 through 2018.
  Heads up: A 2013 Ram 3500 originally came with a gray connector solenoid pack. While it can be replaced with a white connector version, the reverse is not true. A gray connector pack (designed for 5 solenoids internally) cannot be used on an older truck that requires the 6-solenoid white connector pack.

Model Year Variations Within This Range

• 2010-2018: Models from 2010 onward, including the 2013 Ram 3500, were factory-equipped with a 'gray connector' solenoid pack. However, for service and replacement, the earlier 'white connector' style pack is fully compatible and commonly used for all 2007.5-2018 68RFE transmissions.