Engine-Codes - Lexus - P0791 Lexus

P0791 Lexus Code - Intermediate Shaft Speed Sensor 'A' Circuit

- Code Popularity: 6,303 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents

|What are the Possible Causes of the Code P0791 Lexus?

  • Faulty Speed sensor NC (Transmission Revolution Sensor)
  • Speed sensor NC harness is open or shorted
  • Speed sensor NC circuit poor electrical connection
  • Faulty Engine Control Module (ECM)

|How to Fix the P0791 Lexus Code?

Start by checking the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|What is the Cost to Diagnose the Code P0791 Lexus?

Labor: 1.0

The cost to diagnose the P0791 Lexus code is 1.0 hour of labor. The auto repair's diagnosis time and labor rates vary by location, vehicle's make and model, and even your engine type. Most auto repair shops charge between $75 and $150 per hour.

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|What are Code P0791 Lexus Possible Symptoms?

  • Engine Light ON (or Service Engine Soon Warning Light)

|What Does the P0791 Lexus Code Mean?

This sensor detects the rotation speed of the counter gear which indicates the output speed of the transaxle. By comparing the input turbine speed (speed sensor NT) signal with the counter gear speed (speed sensor NC) signal, the Engine Control Module (ECM) detects the shift timing of the gears and appropriately controls the engine torque and hydraulic pressure according to various conditions. As a result, the gears shift smoothly.
The NT terminal of the ECM detects a pulse signal from the speed sensor NT (input RPM). The ECM calculates gear shifts by comparing the signal from speed sensor NT with the signal from speed sensor NC.
While the vehicle is operating in 2nd, 3rd, 4th, or 5th gear with the shift lever in D, if the input shaft speed is less than 300 rpm although the output shaft speed is more than 1000 rpm, the ECM interprets this as a fault, illuminates the MIL and stores the Diagnostic Trouble Code (DTC). P0791 code is detected when the input speed sensor voltage is more than 1.9V or less than 0.1V for 2 seconds or more.

P0791 Lexus Code - Intermediate Shaft Speed Sensor 'A' Circuit

|Need more Information on the P0791 Lexus Code?

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|Need Help with the P0791 Lexus Code?

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