Need a
Repair Manual?
P0730 OBD2: Incorrect Gear Ratio

P0730 OBD2: Incorrect Gear Ratio

OBD-II Code P0730 is defined as a Transmission Control System Malfunction. This code indicates that the Powertrain Computer (PCM) has detected a discrepancy in the gear ratio, primarily due to the difference in RPM readings between the input and output speed sensors.

What Does the P0730 Code Mean?

The P0730 code means that the PCM is seeing a greater than specified RPM difference between the Input RPM Sensor and the Transmission Output RPM Sensor. This situation can occur during gear shifts or even when the vehicle is cruising at a steady speed, often pointing to transmission slipping.

What Causes the P0730 Code?

  • Defective Shift Solenoids
  • Defective Engine Coolant Temperature Sensor
  • Defective Valve Body
  • Dirty transmission fluid that restricts hydraulic passages

What Are the Symptoms of the P0730 Code?

  • Check Engine Light illuminated
  • Vehicle not shifting properly
  • Decrease in fuel economy
  • In some cases, no noticeable symptoms
  • Performance issues like stalling when coming to a stop or misfire-like symptoms

How Serious Is the P0730 Code?

The P0730 code is classified as urgent. This is because it indicates significant malfunctions that could lead to severe vehicle damage or pose safety risks for the driver and passengers. Immediate attention is recommended.

How to Diagnose the P0730 Code

To accurately diagnose the P0730 code, follow these steps:

  1. Record freeze frame data before clearing the code.
  2. Test drive the vehicle under conditions that typically trigger the code, paying attention to engine load, throttle position, RPM, and road speed.
  3. Compare the Input RPM Speed Sensor signal to the Output RPM Speed Sensor signal. If a significant RPM difference is observed at a steady speed, the transmission may be slipping.

Common Repairs for the P0730 Code

  • Replacing defective shift solenoids
  • Replacing or repairing the engine coolant temperature sensor
  • Repairing or replacing the valve body
  • Flushing and replacing the transmission fluid

How Much Does It Cost to Fix the P0730 Code?

The cost to repair the P0730 code can vary widely depending on the underlying cause. Simple repairs like fluid changes may cost a couple of hundred dollars, while more complex repairs, such as replacing internal transmission components, could exceed $1,000.

Can I Fix the P0730 Code Myself?

While some aspects of diagnosing and fixing the P0730 code can be performed by a knowledgeable DIYer, it is crucial to have a good understanding of automatic transmission systems. If you are unsure or lack experience, it is advisable to seek professional assistance to avoid further damage to your vehicle.

About JC Landry

JC is the Senior Editor at eManualOnline.com, GarageSpot.com, and Drive-My.com, as well as the Webmaster of TheMechanicDoctor.com, only to name a few. He's been a certified Master Mechanic for 15 years, working for various car dealers and specialized repair shops before turning towards blogging about cars and EVs in the hope of helping the next generation of automotive technicians. He also loves cats, Johnny Cash and Subarus.

Leave a Reply

Your email address will not be published. Required fields are marked *

;