P0732 - Gear Ratio Incorrect 2nd

Introduction

The DTC P0732 fault code indicates a problem with the second gear transmission ratio of a vehicle. This code is particularly common in vehicles equipped with automatic transmissions and can lead to significant malfunctions, affecting the performance and safety of the vehicle. In the following guide, we will explore the symptoms, causes, diagnosis and possible solutions for DTC P0732, providing useful support for auto repairers.

Symptoms

When a vehicle has the DTC code P0732, you may notice several symptoms, including:

  • Transmission slippage :
    The vehicle may not shift into second gear properly, causing a loss of power.

  • Difficulty in changing :
    You may experience harsh or delayed gear changes, particularly when shifting from first to second gear.

  • Warning light comes on :
    The engine light may come on on the dashboard, indicating that there is a problem with the transmission.

  • Increased fuel consumption :
    An incorrect gear ratio can affect fuel efficiency, leading to increased fuel consumption.

  • Abnormal vibrations :
    Vibrations may occur when shifting gears, indicating a mechanical problem.

Cause

The causes of the DTC code P0732 can be many and may include:

  • Speed sensor problems :
    A faulty speed sensor can give incorrect readings to the ECU, causing the transmission system to fail to calculate the gear ratio correctly.

  • Engine control unit (ECU) malfunction :
    A damaged or malfunctioning ECU can affect the management of the transmission.

  • Mechanical problems in the transmission :
    Internal components, such as worn or damaged gears, can cause an incorrect gear ratio.

  • Low transmission fluid pressure :
    If the fluid pressure is insufficient, the transmission may not function properly.

  • Clogged filters :
    Dirty or clogged filters can impede the flow of transmission fluid, affecting its operation.

Diagnosis

Diagnosing DTC P0732 requires a systematic approach. Here are the basic steps:

  1. Vehicle Scan :
    Use an OBD-II scanner to confirm the presence of DTC code P0732 and to check for any related codes, such as P0730 (Incorrect Gear Ratio) or P0715 (Transmission Speed Sensor).

  2. Visual inspection :
    Physically inspect the transmission wiring and connectors for any signs of wear, damage, or corrosion.

  3. Checking the fluid level :
    Check the level and condition of the transmission fluid. Dirty or contaminated fluid should be replaced.

  4. Speed Sensor Test :
    Use a multimeter to test the transmission speed sensor, verifying that it is functioning properly and sending appropriate signals to the ECU.

  5. Fluid pressure control :
    If possible, check the transmission fluid pressure to ensure it is within the manufacturer's specifications.

  6. Functional test :
    Perform a test drive to check the transmission behavior and identify any anomalies.

Resolution and Repair

Once the cause of the DTC P0732 code has been identified, there are several repair measures that can be taken. Here are some common solutions:

  • Replacing the speed sensor :
    If the speed sensor is faulty, it must be replaced.

  • Reset or replace the ECU :
    If the engine control unit is malfunctioning, it may need to be repaired or replaced.

  • Transmission Repair :
    If gears or other internal components are damaged, appropriate repairs or replacements must be made.

  • Changing the transmission fluid :
    If the fluid is dirty or contaminated, perform a fluid change and replace the transmission filter.

  • Fluid pressure regulation :
    If fluid pressure is low due to a faulty pump, the transmission pump may need to be replaced.

Insight into the Components Involved

Transmission Sensors and Actuators

In an automatic transmission system, several components work together to ensure smooth and precise operation. Among them, sensors and actuators play a crucial role:

  • Transmission speed sensor :
    This sensor measures the speed of the gears inside the transmission and sends this information to the ECU. If the sensor is faulty, the ECU may receive incorrect readings, leading to incorrect gear changes.

  • Control valve actuator :
    This component regulates the flow of transmission fluid, affecting pressure and gear shifting. A malfunctioning actuator can prevent the transmission from functioning properly.

  • Transmission pump :
    The pump is responsible for circulating fluid through the system. A faulty pump can cause low fluid pressure, which can negatively affect the operation of the transmission.

Conclusions

DTC P0732 is a significant problem for a vehicle’s transmission. However, by following a systematic approach to diagnosis and repair, you can effectively identify and resolve the problem. It is essential to have a thorough understanding of the various mechanical and electrical components involved to ensure a successful repair. Keeping your vehicle in tip-top condition and paying attention to warning signs can prevent future problems and ensure safe and reliable driving.

Investing in ongoing training and updates on transmission technologies is essential for any auto repairer who wants to remain competitive in the industry.

Important
Not all OBD2 codes used by one manufacturer are used by other brands, and may not have the same meaning.
The information presented here is for informational purposes only. We are not responsible for any actions you take on your vehicle. If you have any concerns about repairing your vehicle, please contact your repair shop.