P0729 - OBD II Trouble Code

Our automotive experts have put together the following information about the P0729 diagnostic trouble code. We've provided the common symptoms that occur when this code is set along with the frequent repairs that address the issues related to the P0729 code.

What Does P0729 Code Mean?

OBD-II Code P0729 is defined as a Gear 6 Incorrect Ratio

The Input Speed Sensor tells the Transmission Control Module (TCM) how fast the engine is spinning so the correct gear can be engaged. The Output Speed Sensor tells the Transmission Control Module (TCM) how fast the output shaft of the transmission is spinning so it can verify the correct gear is engaged. The TCM compares both signals to verify the transmission is in the desired gear. If it is determined that the transmission is not in the desired gear, the engine control module (PCM) or TCM will set code P0729.

P0729 Symptoms

• Increased fuel consumption
• Transmission may not shift properly

Common Problems That Trigger the P0729 Code

• Internal transmission failure
• Powertrain Control Module (PCM) failure
• Transmission Control Module (TCM) failure
• Transmission fluid level is low
• Transmission valve body failure
• Wiring issue

Common Repairs Needed for the P0729 Code

• Automatic Transmission Fluid/Filter Change