P0791 Code - Intermediate Shaft Speed Sensor 'A' Circuit
Quick Answer
This sensor detects the rotation speed of the counter gear which indicates the output speed of the transaxle. Common causes include Faulty Speed sensor NC (Transmission Revolution Sensor), Speed sensor NC harness is open or shorted, Speed sensor NC circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P0791 indicates Intermediate Shaft Speed Sensor 'A' Circuit.
- Common causes
- Common causes include Faulty Speed sensor NC (Transmission Revolution Sensor), Speed sensor NC harness is open or shorted, Speed sensor NC circuit poor electrical connection.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P0791 Description
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.
What are the Possible Causes of the DTC P0791?
- 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 DTC P0791?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0791 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Information for Specific Makes
- P0791 Audi — Intermediate Shaft Speed Sensor 'A' Circuit
- P0791 Chrysler — Transfer Speed Sensor Circuit
- P0791 Dodge — Transfer Speed Sensor Circuit
- P0791 Jeep — Transfer Speed Sensor Circuit
- P0791 Lexus — Intermediate Shaft Speed Sensor 'A' Circuit
- P0791 Mazda — Intermediate Shaft Speed Sensor 'A' Circuit
- P0791 Scion — Intermediate Shaft Speed Sensor 'A' Circuit
- P0791 Toyota — Intermediate Shaft Speed Sensor 'A' Circuit
- P0791 Volkswagen — Intermediate Shaft Speed Sensor 'A' Circuit
Frequently Asked Questions about P0791 Code
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