What is the P0728 fault code description? What is the description of Engine Speed Input Circuit Intermittent/Intermittent fault? How can I fix the fault code P0728? What are the causes and symptoms of the P0728 error code?
What is the P0728 Fault code? What does it signify?
The powertrain control module or transmission control module (TCM), which controls automatic transmission vehicles, must know four things before it can decide when to shift gears. These are engine speed, engine load and current selected gear.
All shift points are determined by engine speed. The most important parameter of all four parameters is the engine speed (RPM), also known as revolutions per minute. The PCM/TCM program is designed to shift gears at predetermined engine speeds in order to minimize component damage and exhaust emissions. This will maximize engine performance while using minimal fuel.
To allow the PCM to decide the right time to shift gears it must read the RPMs from engine. This sensor is the motor input shaftspeed sensor. This speed sensor, also known as the transmission shaft speed sensor, is typically located near the front end of the transmission shaft.
If the PCM/TCM is receiving an intermittent or irregular signal from the engine shaft speed sensor over a specific period of time, and under certain conditions fault code P0728 will trigger the check engine lamp to notify the driver.
The P0728 fault code can affect vehicles of all makes and models, including but not limited to: Volvo, Toyota, Volkswagen or Mitsubishi, Mercedes-Benz. Chrysler, Dodge, Jeep. Ford. Chevrolet.
What causes the P0728 Fault code?
These are the most common reasons that P0728 codes are triggered:
- – Defective motor input shaft speed sensor
- – There are metal deposits at the tip end of the input shaft speed sensor
- – Defective gearbox output shaft speed sensor
- – Defective input shaftspeed sensor reluctor wheel
- – Defective crankshaft position sensor
- – Damaged wires to sensor, loose connectors and open or short circuit problems
- – Defective shift solenoid
- – Transmission fluid that is not working properly or is missing
- – A PCM/TCM is defective or must be reprogrammed
What are the symptoms of P0728 Malfunction Code?
These symptoms may be present in vehicles with code P0728.
- – Illumination for the check engine light
- – Requires hard, delayed and unpredictable shifting
- Transmission cannot change gears
- Gearbox slip / slip
- – Increased fuel use
- – Speedometer that is non-working or wavy
- Engine misfires
- – Engine hesitation during acceleration
- – Engine stalling during idling, or when it stops
- – PCM may enter failsafe mode (limp Mode) to limit engine power
How do I fix the P0728 fault code?
First, the PCM’s fault codes must be read using a scanner. Usually, P0728 is found along with other codes. After clearing the codes, your mechanic should test the vehicle to determine if it is returning. Next, inspect the cables and connectors to the motor input shaft speed sensor circuit and cable. Any corrosion should be cleaned and replaced with newer cables. The vehicle should then be tested again to make sure that loose connectors are repaired. Your mechanic should verify the reference voltage for the input shaft speed sensor if the code comes back. Both circuits should be tested for continuity and resistance. The sensor should fail these tests and be replaced.
Near the front of the shaft is the engine input shaft speed sensor. It can be found inside the transmission box. The rubber O-ring seals the sensor housing to the transmission case. To collect any fluids that may have escaped from the sensor housing, you should place it under the transmission. Hot transmission fluid can cause serious health problems if the sensor is removed from its housing.
The following repairs may be able to resolve the P0728 fault code:
- Replacing a defective transmission input shaft speed sensor
- – Replacing the defective transmission output shaft speed sensor
- – Replacing the defective crankshaft position sensor
- Repair damaged wires, connectors and open or short circuits to sensors
- – Replacing defective motor input shaft speed sensor reluctor wheels
- – Replacing a damaged shift solenoid
- – Refilling the transmission fluid that is not available
- – Replacing dirty or contaminated transmission fluid
- – Replacement of or reprogramming the PCM/TCM
How Serious Is the P0728 Fault Coding?
A code P0728 should be set on your vehicle. This code should be taken seriously and dealt with immediately. A sudden engine stop in heavy traffic can pose a risk of an accident. This code can lead to many problems in driving, such as increased fuel consumption and engine stumbling while accelerating. The transmission might also be damaged if it isn’t properly shifted or stuck.
