P0731 2015 GMC Sierra Code - Transmission 1st Gear Ratio Incorrect
Quick Answer
The transmission turbine speed sensor and vehicle speed sensor are hall-effect sensors. Common causes include Low transmission fluid level, Shift solenoid mechanical fault, Faulty Turbine Sensor. 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
- P0731 2015 GMC Sierra indicates Transmission 1st Gear Ratio Incorrect.
- Common causes
- Common causes include Low transmission fluid level, Shift solenoid mechanical fault, Faulty Turbine Sensor.
- 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 P0731 2015 GMC Sierra Description
The TCM provides a 9 V reference circuit and a signal circuit to each of the sensors. As the 1-2-3-4-5-6 clutch piston housing and transmission output shaft or transfer case output rotates, the sensors produce a signal frequency based on the teeth on the reluctor wheel. The TCM calculates the transmission gear ratio based on the speed sensor signals and compares the calculated gear ratio to the commanded gear ratio.
The Diagnostic Trouble Code (DTC) will be set when the TCM detects the calculated gear ratio with 1st gear commanded differs from the known 1st gear ratio for 2 s.
What are the Possible Causes of the DTC P0731 2015 GMC Sierra?
- Low transmission fluid level
- Shift solenoid mechanical fault
- Faulty Turbine Sensor
- Faulty Output Speed Sensor
How to Fix the DTC P0731 2015 GMC Sierra?
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.
Code Tech Notes
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P0731 2015 GMC Sierra 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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Frequently Asked Questions about P0731 2015 GMC Sierra Code
1. What does OBDII code P0731 mean on a 2015 GMC Sierra?
Code P0731 indicates that the transmission control module (TCM) has detected an incorrect gear ratio in 1st gear.
2. What are the common symptoms of P0731 in a 2015 GMC Sierra?
Symptoms may include difficulty shifting into or out of 1st gear, slipping transmission, reduced acceleration, poor fuel efficiency, and the check engine light being illuminated.
3. What causes the P0731 code in a 2015 GMC Sierra?
Common causes include low or dirty transmission fluid, a faulty shift solenoid, damaged transmission components (like clutches or bands), or a malfunctioning transmission control module.
4. Can low transmission fluid trigger code P0731?
Yes, low or dirty transmission fluid can affect hydraulic pressure and cause incorrect gear ratios, triggering the P0731 code.
5. How do you diagnose the P0731 code on a 2015 GMC Sierra?
Diagnosis involves checking the transmission fluid level and condition, inspecting wiring and connectors, testing shift solenoids, and possibly using a scan tool to monitor transmission data.
6. Can driving with the P0731 code damage my 2015 GMC Sierra?
Yes, continuing to drive with this code can cause further damage to the transmission, leading to more expensive repairs.
7. How do you fix the P0731 code on a 2015 GMC Sierra?
Repairs may include replacing or servicing the transmission fluid, repairing or replacing faulty shift solenoids, fixing damaged gears or clutches, or reprogramming the TCM.
8. How much does it cost to fix the P0731 code in a 2015 GMC Sierra?
Repair costs can vary widely, from $100 for a fluid change to several thousand dollars for transmission rebuilds or replacements.
9. Can a bad speed sensor cause the P0731 code on a GMC Sierra?
Yes, a faulty speed sensor can send incorrect data to the TCM, leading to gear ratio errors and triggering the P0731 code.
10. Is it safe to drive my 2015 GMC Sierra with the P0731 code?
It’s not recommended to drive with this code as it may worsen transmission problems and leave you stranded. Have the issue diagnosed and repaired promptly.
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