P0989 Code: Transmission Fluid Pressure Sensor/Switch “E” Circuit Low

The transmission fluid pressure (TFP) sensor/switch plays a critical part in ensuring smooth shifting while driving. The PCM or TCM will log a P0989 code if it detects a problem with the transmission fluid pressure sensor/switch (in the E position) or its circuit.

What Does the P0989 Code Mean?

Diagnostic trouble code (DTC) P0989 stands for “Transmission Fluid Pressure Sensor/Switch E Circuit.”

The transmission fluid pressure sensor is usually located on the side of the transmission’s valve body. Some sensor models are fastened to the side of the transmission case.

The sensor turns the mechanical pressure applied by the transmission fluid into a voltage signal. It transmits the signal to the TCM or PCM, which shares the readings with other controllers when the need comes up.

Thanks to the transmission fluid pressure sensor readings, the control module can determine the right transmission operating pressure or when to shift transmission gears.

The PCM regularly checks the readings sent by the transmission fluid pressure sensor. It compares the inputs with the normal operating voltages recorded in its memory. If the control module finds a discrepancy, it will set the generic powertrain code P0989.

Note: The definition of code P0989 can differ according to the vehicle manufacturer. Check the appropriate repair manual or repair database for the exact code definition.

What are the Common Causes of a Code P0989?

• Low transmission fluid level
• Bad transmission fluid pressure sensor
• Corroded, ground, shorted, or loose wires and connectors
• Faulty TCM
• Internal transmission or valve body problems

What are the Common Symptoms of a Code P0989?

• Illuminated check engine light
• Higher fuel consumption
• Improperly shifting transmission

How to Diagnose the P0989 Code

The P0989 code is a generic powertrain code that various makes and models can log. However, it can be caused by different problems, depending on the vehicle. So there isn’t a single solution that applies to all instances of a code P0989.

If you’re not confident about diagnosing your vehicle’s transmission fluid pressure sensor/switch on your own, it’s best to take it to an auto repair shop for a proper diagnosis.

How to Fix the P0989 Code

Without the right tools and training to work on the transmission fluid pressure sensor, trying to repair a P0989 code can prove challenging. In those cases, it’s a good idea to let technicians handle the repair job.

But if you have advanced technical knowledge and hands-on experience when it comes to testing and replacing the transmission fluid pressure sensor, you can resolve the issue yourself. Keep in mind that the location of the “E” circuit can vary depending on the vehicle. So make sure you consult a vehicle-specific repair manual or an online repair database before you get started.