P0706 on 2005-2014 Chrysler 300: Transmission Range Sensor Causes and Fixes

What's Unique About the 2005-2014 Chrysler 300

The Chrysler 300s in this year range, particularly V8 models and early V6s, use a Mercedes-designed 5-speed automatic transmission known as the NAG1, W5A580, or by its Mercedes designation, the 722.6. Unlike many vehicles with an external, easy-to-replace range sensor, the NAG1's sensor function is built into the 'conductor plate'—an electronic board mounted on the valve body inside the transmission pan. This design makes the repair more involved and also prone to a well-known issue where the main 13-pin electrical connector leaks fluid, causing a host of electronic problems.

Generation note: This range covers the first generation (LX, 2005-2010) and the start of the second generation (LD, 2011-2014). The 5-speed NAG1 transmission, where this issue is most common, was used in most V8 and some V6 models across both generations. Later second-gen V6 models switched to an 8-speed transmission which has a different design and is not the focus of this guide.

Symptoms You May Notice

• Transmission stuck in 'limp mode' (usually 2nd gear).
• Check Engine Light is illuminated.
• Harsh, erratic, or failed gear shifts.
• Vehicle may not start, or only starts in Neutral.
• Shifter may be difficult to move out of Park.
• Reverse lights may not illuminate.
• Message on dash such as 'Transmission, Visit Workshop'.

Most Likely Causes

1. Failed Conductor Plate 🔴 High Probability The plastic housing and integrated sensors on the NAG1 conductor plate are known to become brittle and fail from constant heat cycles inside the transmission. The speed sensors housed on the plate are a primary point of failure.
   How to confirm: A professional scan tool can monitor live data from the transmission's input/output speed sensors and range sensor. If the readings are erratic, absent, or implausible, the conductor plate is the likely culprit. Often accompanied by speed sensor codes like P0715 or P0720.
   Typical fix: Replace the conductor plate, which is located on top of the valve body inside the transmission. This job is typically done along with a new filter, pan gasket, 13-pin connector, and fresh fluid meeting the MB 236.14 specification.
   Est. part cost: $120-$250
2. Leaking 13-Pin Electrical Connector Sleeve 🟡 Medium Probability The O-rings on the connector sleeve that plugs into the transmission housing are a known failure point, allowing transmission fluid to seep out and contaminate the electrical connection. This is considered a mandatory replacement item when servicing the conductor plate.
   How to confirm: Visually inspect the round 13-pin connector on the front passenger side of the transmission. If it is wet with red transmission fluid, it is leaking and must be replaced.
   Typical fix: Replace the connector sleeve. This is an inexpensive part that should be replaced anytime the conductor plate is serviced, as it is a primary cause of related electrical faults.
   Est. part cost: $10-$25
3. Low or Incorrect Transmission Fluid ⚪ Low Probability → Shop Transmission Assembly These transmissions are sensitive to fluid level and type. They do not have a factory-installed dipstick, making checks difficult for owners. Using ATF+4 instead of the required NAG1-specific fluid is a common mistake that can cause shifting problems.
   How to confirm: Check the transmission fluid level using the correct dipstick tool (e.g., Miller 9336A) and a temperature chart. Note the color and smell of the fluid; it should be bright red and not smell burnt. Confirm the correct fluid type is being used (meets MB 236.14 spec).
   Typical fix: Perform a transmission fluid and filter change using the correct fluid type. If the fluid is very dark or contains metal particles, more significant internal damage may be present.
   Est. part cost: $100-$200

Rare But Worth Checking

• Faulty Transmission Control Module (TCM): → Shop Transmission Assembly This is rare, but transmission fluid can wick up the wiring harness from a leaking 13-pin connector and contaminate the TCM, causing it to fail. Always inspect the TCM connectors for fluid if the transmission connector is leaking.
• Damaged Wiring Harness: Physical damage to the wiring between the transmission and the TCM can cause signal loss, but this is less common than component failure.

Diagnosis Steps

1. Scan the TCM for any other transmission-related codes to get a full picture. Codes for speed sensors (P0715, P0720, P2767) strongly point to the conductor plate.
2. Check the transmission fluid level and condition using the appropriate dipstick tool (e.g., Miller 9336A) and a temperature chart. The NAG1 does not come with one from the factory.
3. Visually inspect the 13-pin electrical connector on the transmission for any signs of fluid leakage. If wet, plan to replace it.
4. Using an advanced scan tool, monitor the live data for the transmission range sensor and input/output speed sensors while shifting gears. Irrational readings point towards a faulty conductor plate.
5. If the connector was leaking, inspect the wiring harness and the TCM connectors (often located in the passenger footwell area) for any migrated fluid.
6. If all sensors and wiring appear functional, the issue may lie within the valve body solenoids or, rarely, the TCM itself.

Parts You'll Likely Need

• Transmission Conductor Plate (OEM #52108308AC (supersedes 52108308AB)) — This is the most common failure point for P0706 on the NAG1 transmission, as it houses the range sensor electronics.
  Trusted brands: Mopar, Dorman, Vaico (OEM Supplier), Standard Motor Products
  OEM price range: $200-$275
  Aftermarket price range: $120-$180
• Transmission Electrical Connector Sleeve (OEM #68021352AA) — This connector's O-rings frequently fail, causing fluid leaks that lead to electrical issues. It should always be replaced when servicing the conductor plate.
  Trusted brands: Mopar, Vaico, Dorman
  OEM price range: $15-$25
  Aftermarket price range: $10-$20
• Transmission Fluid (NAG1/722.6 Spec) (OEM #Mopar ATF NAG1, Shell ATF 134, Fuchs Titan ATF 4134) — CRITICAL: This transmission does NOT use ATF+4. It requires fluid meeting MB-Approval 236.14. Using the wrong fluid will cause damage.
  Trusted brands: Valvoline MaxLife Multi-Vehicle ATF, Pentosin ATF134, Shell Spirax S6 ATF 134M
  OEM price range: $18-$25 per quart
  Aftermarket price range: $8-$15 per quart
• Transmission Filter and Pan Gasket Kit — Required for any job that involves dropping the transmission pan.
  Trusted brands: Mopar, Mahle, ATP, Wix
  OEM price range: $40-$60
  Aftermarket price range: $25-$40

Related Codes That Often Appear With This One

• P0715 — Input Speed Sensor Circuit Malfunction. This sensor is also located on the conductor plate.
• P0720 — Output Speed Sensor Circuit Malfunction. This sensor is also located on the conductor plate.
• P2767 — Input/Turbine Speed Sensor 'B' Circuit No Signal. Another code pointing directly to the conductor plate sensors.

Technical Service Bulletins (TSBs) & Recalls

• While no TSB directly addresses P0706, TSB 21-015-07 and similar software updates for the TCM were released to address shift quality concerns on the NAG1. It's worth checking if the vehicle's software is up to date, though it is unlikely to fix a hardware failure causing P0706.

Platform-Specific Known Issues

• The NAG1 (W5A580) transmission's conductor plate is a well-documented, common point of failure across all Chrysler, Dodge, and Jeep vehicles that use it.
• Fluid wicking from the 13-pin connector up to the TCM is a known issue that can cause more widespread and expensive damage if the initial leak is not addressed.
• Confusion over the correct transmission fluid is common. Many shops and owners mistakenly use ATF+4, which is incorrect for the Mercedes-derived NAG1 transmission and can lead to performance issues.

Mechanic-Grade Diagnostic Values

• Sensor Supply Voltage at TCM — expected: 4.8 to 7.2 volts. Failure: A voltage reading above 7.2 volts will set a fault code.
• CAN C Bus Resistance — expected: 60.0 ohms (± 3.0 ohms) between CAN C Bus (+) and (-) circuits at the PCM harness connector.. Failure: A reading outside this range indicates a problem on the communication bus, which could mimic a sensor failure.

Scan Tool Commands That Help

• Chrysler wiTECH or equivalent professional scanner: TCM Quick Learn / Reset Transmission Adaptations — This procedure should be performed after replacing the conductor plate or valve body. It forces the TCM to relearn the clutch fill volumes and shift timing, which is critical for proper shift quality after the repair. Failure to do so may result in harsh or erratic shifting.
• Chrysler wiTECH: Re-flash PCM — In some cases, particularly when replacing the TCM itself, the new module may not be recognized. A PCM re-flash may be required to complete the TCM update and establish communication.

Wiring & Ground Locations

• TCM (Transmission Control Module) — Located under the left side of the instrument panel, near the steering column for left-hand drive vehicles.. This is the computer that receives the signal from the conductor plate's range sensor. Fluid that has wicked up the harness from a leaking 13-pin connector can damage this module, causing P0706 and other communication codes.
• Ground Circuits (Z910 or Z912) — These are the ground circuits for the TCM, located in the TCM C1 harness connector.. A poor ground connection to the TCM can cause a host of electrical issues, including incorrect readings from sensors and setting false codes. A diagnostic step for a non-responsive TCM is to check these ground circuits for an open.
• 13-Pin Transmission Connector — On the front passenger side of the transmission housing.. This is the single point of connection for all electronics inside the transmission, including the conductor plate. It is a notorious leak point. A 7mm bolt inside the connector sleeve must be loosened to remove it.

Real Owner Repair Stories

• YouTube user comment on a repair video (2005 Dodge Magnum RT (shares platform and NAG1 transmission)) — After a used transmission was installed, the car developed code P2767 (No Speed Sensor 2 Signal) and 'Lost Communication with TCM', resulting in limp mode.
  ❌ Tried (didn't work) A repair shop quoted $750 to fix the issue without a clear diagnosis.
  ✅ What actually fixed it The owner followed the video's instructions, replaced the conductor plate themselves, and discovered the previous shop had not even changed the old, black fluid or filter. The conductor plate replacement resolved the codes and limp mode.
• YouTube video by 'ANDERZÉN' (Mercedes ML55 AMG with 722.6 / NAG1 transmission at ~200,000 miles) — Transmission got stuck in second gear when hot after a long highway drive.
  ❌ Tried (didn't work) A recent fluid change did not prevent the issue.
  ✅ What actually fixed it The owner diagnosed the issue as a failing conductor plate, likely due to failing solder joints or sensors on the plate that become problematic when hot. The video documents the successful replacement of the conductor plate.

OEM Part Supersession History

• 52108308AB → 52108308AC — Standard part revision and improvement over time.
  Heads up: The new part (52108308AC) is a direct replacement for the old one and should be used for all repairs.

Model Year Variations Within This Range

• 2011-2014: While V8 models largely retained the 5-speed NAG1 transmission, many V6 models began transitioning to a new ZF-designed 8-speed automatic transmission starting in the 2012 model year. This guide and the P0706 fault as described are specific to the 5-speed NAG1. The 8-speed has a completely different internal mechatronic unit and diagnostic procedure.
• 2005-2010: The Transmission Control Module (TCM) for the first generation (LX) is located under the left side of the instrument panel.

Diagnostic Flowchart

Other Known Issues on This Vehicle

Issues unrelated to this code that are worth knowing about as an owner of this generation:

• Shifter Stuck in Park ('Pink Thingy' Failure) 🔴 High — Extremely common on 2005-2007 models. A small pink plastic lever in the shifter assembly breaks, immobilizing the vehicle.
• Front Suspension Clunking/Rattling 🟠 Medium — Very common across all years. Typically caused by worn sway bar bushings, end links, or tension struts. Creates noise over bumps.
• HEMI (5.7L) MDS Lifter Failure 🔴 High — A significant issue where lifters for the Multi-Displacement System (MDS) fail, often causing a 'tick' that can progress to camshaft damage and major engine repair.
• Alternator Failure 🔴 High — Common, especially on V8 models. The alternator is located in a hot valley at the bottom-front of the engine, leading to premature failure and potential stalling.
• Faulty Electrical Systems / TIPM Issues 🟠 Medium — Owners report various electrical gremlins, including issues with the Totally Integrated Power Module (TIPM), which can cause problems with fuel pump operation, lights, and power windows.
• Power Window Regulator/Motor Failure 🟡 Low — Common across many model years, where the window may stop working due to a failed motor or broken regulator cable.

Used vs. New Parts: Buying Guide for This Vehicle

When a used part is the smart pick: A used valve body can be a viable option if your original is physically damaged, but it should be fitted with a NEW conductor plate. Buying a complete used transmission solely for this P0706 code is almost never cost-effective. A used TCM may be an option if yours is confirmed fried by fluid intrusion, but ensure it's from the exact same model and year.

Donor-vehicle mileage cap: roughly under 80000 miles for the part to have meaningful remaining life.

What to inspect on the donor part:

• For a valve body, look for clean fluid passages and no signs of scoring or heavy sludge.
• For a TCM, inspect the connectors for any signs of corrosion or fluid contamination.
• Verify the donor vehicle was not involved in a flood or severe front-end collision.

OEM-only on this vehicle (don't cheap out):

• Transmission Conductor Plate: While high-quality aftermarket options exist, many professional technicians and forum users strongly recommend using a genuine Mopar or OEM-supplier (e.g., Vaico) conductor plate for maximum reliability and to avoid repeat failures.

Aftermarket brands forum-validated for this vehicle:

• Conductor Plate: Dorman, Standard Motor Products (SMP), Vaico.
• Fluid: Valvoline MaxLife Multi-Vehicle ATF, Pentosin ATF134, Shell Spirax S6 ATF 134M.
• Filter/Gasket: Mahle, Wix, ATP.

Brands owners have reported issues with on this vehicle:

• Unbranded, no-name conductor plates from online marketplaces are a significant gamble and a common source of premature failure, often within months. The labor involved in the repair is too high to risk using a part of unknown quality.

Real Owner Stories

Aggregated from forums and TSBs cited above. Mileages and costs reflect what owners reported in those sources.

Related OBD-II Codes

• P0715 — Input speed sensor circuit malfunction; often accompanies P0706 when the conductor plate's integrated sensors fail.
• P0720 — Output speed sensor circuit error; a primary point of failure on the NAG1 conductor plate that triggers transmission fault codes.
• P2767 — Input/Turbine Speed Sensor B Circuit No Signal; another speed sensor code that strongly points toward a faulty conductor plate.

Frequently Asked Questions