December 23, 2023

Acura RLX (2014-2017) Rough Shift? Let us Help.

Acura RLX D4 rough shift engine light As a long-time owner of an Acura RLX I’ve experienced not only the engine light, but also the D4 blinking and the rough shift that follows. The RLX, while a reliable vehicle, isn’t immune to issues, especially concerning its transmission system.  I’ll share my experience in diagnosing and fixing this common transmission problem.

Running rough?

Check for Recalls

Symptoms and Troubleshooting your Acura RLX

  1. Rough Shifting: This is the most common issue, where the transmission doesn’t shift smoothly between gears.
  2. Blinking “D4” Light and Check Engine Light: These warning lights often illuminate together, signaling a problem.
  3. OBD Codes: The codes P0700, P0730, P0740, P0780, P1768, and P1768 are significant indicators of transmission problems. Other relevant OBD codes include P0715, P0720, and P1750, which also point to transmission-related issues.

Rough Shifting and Warning Lights

One of the most common symptoms I’ve noticed is rough shifting. This issue is often accompanied by the blinking of the “D4” light and the illumination of the check engine light. When you experience this, it’s a clear signal that your vehicle needs attention.

OBD Codes

The On-Board Diagnostics (OBD) system in your RLX can generate various codes. Some common codes include P0700, P0730, P0740, P0780, and P1768. Each code points to a different aspect of the transmission problem.  See all the OBD codes here.

  • P0700: Transmission Control System Malfunction
  • P0730: Incorrect Gear Ratio
  • P0740: Torque Converter Clutch Circuit Malfunction
  • P0780: Shift Malfunction
  • P1768: Performance / Normal / Winter Mode Input Malfunction

Additional OBD Codes Related to Transmission Issues

  • P0715: Input/Turbine Speed Sensor Circuit Malfunction
  • P0720: Output Speed Sensor Circuit Malfunction
  • P0741: Torque Converter Clutch Circuit Performance or Stuck Off
  • P0750: Shift Solenoid A Malfunction

Mechanical Failure vs. Sensor or Fluid Issues

Let’s determine whether the issue is mechanical or related to a sensor or dirty fluid.  If the transmission shifts roughly, it’s likely a mechanical failure. If it performs normally but still shows warning signs, a faulty sensor or dirty fluid might be the culprits.  Also, by changing the transmission fluid, a complete mechanical failure may be delayed.

DIY: Replacing Transmission Fluid in Acura RLX

Tools and Materials Needed

  • Transmission Fluid (specific to Acura RLX)
  • Drain Pan
  • Socket Wrench
  • New Transmission Filter (optional)
  • Gloves and Safety Glasses

Steps

  1. Locate the Transmission Fluid Dipstick: Check your RLX manual for the exact location.
  2. Warm Up the Car: Run the engine for a few minutes.
  3. Position the Drain Pan: Place it under the transmission drain plug.
  4. Remove the Drain Plug: Use the socket wrench to remove it and drain the old fluid.
  5. Replace the Transmission Filter (Optional): This is a good practice when changing fluid.
  6. Refill with New Fluid: Use the dipstick hole and follow the manual for the correct amount.
  7. Check for Leaks: Start the engine and look for any leaks.
  8. Dispose of Old Fluid Properly: Take it to a recycling center or auto shop.

Final Thoughts

Understanding the symptoms and troubleshooting, particularly with an engine light, can make a difference. Regular maintenance, like changing transmission fluid helps prolong the life of your vehicle. Always consult a professional mechanic if you’re unsure or if the problem persists.