P0730: Incorrect Gear Ratio OBD-II Trouble Code

In This Guide

The P0730 OBD-II code is a generic trouble code, meaning it applies to all makes & models of vehicles from 1996 to present. It can be caused by anything from shift solenoid problems to dirty transmission fluid. We will explore this trouble code more closely below.

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What Does P0730 Mean?

“Transmission Control System Malfunction” is the definition of OBD-II Trouble Code P0730.

By automatically selecting different “speeds” or gear ratios to deliver power to the wheels, an automatic transmission’s goal is to match the optimal torque and power characteristics of the engine to the desired speed and rate of acceleration of the driver.

When the TCM (or transmission control module) sees an RPM difference (rotational speed) between the transmission output RPM sensor and input RPM sensor that is greater than a certain value, the P0730 code is triggered. This can happen while shifting between gears or when driving at a steady speed in a particular gear.

Symptoms of P0730

  • Illumination of the Check Engine light
  • Fuel economy decreases
  • Shifting of the vehicle is delayed or goes into wrong gear
  • Transmission slipping
  • There may be misfire-like symptoms, dying when coming to a stop after freeway driving, or other performance issues in some cases
  • The driver may not notice any adverse conditions in some cases

Common Causes of P0730

  • Faulty torque converter clutch
  • Faulty shift solenoids
  • Blockage on the inside of the transmission main control
  • Internal mechanical failure of the transmission
  • Blockage in fluid lines
  • Clogged fluid filter or worn pump
  • Dirty or low transmission fluid

How to Diagnose the P0730 Code?

The level of fluid in the transmission should be noted and checked for quality before doing any other diagnostic tests. You should replace any dirty or old fluid.

In the hands of a qualified mechanic, an OBD-II scanner diagnoses the P0730 code. With this, they can view any needed info from the engine in real-time. The technician will take the vehicle for a test drive after clearing the code.

The code is due to an actual condition within the transmission if it comes back again. To determine if the engine stall speed fits factory specifications, the mechanic might perform a torque converter stall speed test.

Common Mistakes When Diagnosing

Common misdiagnoses include an internal transmission problem and engine misfire. The symptoms you are experiencing may simply be due to dirty or low transmission fluid. The transmission problems that are causing the trouble code may be resolved by simply replacing or topping off the fluid.

Fair Replacement Transmission Cost by Vehicle

  1. Find your transmission model in the table below for fair prices from reputable suppliers. Also fair labor cost for local installation at a local auto repair shop.

  2. Get a free estimate on a remanufactured transmission by email.

Fair Remanufactured Transmission Price Ranges by Transmission Model Updated July 2018

transmission repair cost
Download Replacement Transmission Cost Guide PDF

What Repairs Will Fix the P0730 Code?

  • Wires connecting sensors to the transmission control module and other electrical connections should be inspected.
  • Any damaged or corroded wires in and near the transmission control module should be repaired or replaced.
  • Parts in the transmission might need to be repaired or replaced if the transmission wiring and fluid are all in working condition.
  • The transmission must be removed if there is a problem with the torque converter, shift solenoids, or pump.
  • To be sure that it operates without the P0730 code or any other trouble codes, the transmission should be reinstalled and inspected once the needed repairs are completed and before testing.

Codes Related to P0730

  • P0729
  • P0731
  • P0732
  • P0733
  • P0734
  • P0735
  • P0736

Need more help with a P0730 code?

If the above guide does not answer your questions, comment below with the code(s) and symptoms you are getting along with the make, model, and year of your car.

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