P2771 2016 GMC Sierra Code - Four Wheel Drive Low Switch Circuit
Quick Answer
For vehicles equipped with an active transfer case, the four-wheel drive (4WD) low circuit consists of the Powertrain Control Module (PCM), a transfer case control module, and the circuit wiring. Common causes include Faulty Transfer Case Shift Control Switch, Transfer Case Shift Control Switch harness is open or shorted, Transfer Case Shift Control Switch 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
- P2771 2016 GMC Sierra indicates Four Wheel Drive Low Switch Circuit.
- Common causes
- Common causes include Faulty Transfer Case Shift Control Switch, Transfer Case Shift Control Switch harness is open or shorted, Transfer Case Shift Control Switch 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 P2771 2016 GMC Sierra Description
For vehicles not equipped with an active transfer case, the 4WD low circuit consists of the PCM, a transfer case switch, and the circuit wiring. The transfer case switch controls the 4WD low signal on the signal circuit. When the operator selects 4WD low, the transfer case switch closes, and the 4WD low signal voltage on the signal circuit changes from ignition voltage to zero volts. The PCM then compensates for transfer case gear reduction in the transmission output shaft speed (OSS) sensor signal. The PCM uses the transmission OSS sensor signal to adjust shift points, line pressure, and TCC scheduling.
What are the Possible Causes of the DTC P2771 2016 GMC Sierra?
- Faulty Transfer Case Shift Control Switch
- Transfer Case Shift Control Switch harness is open or shorted
- Transfer Case Shift Control Switch circuit poor electrical connection
How to Fix the DTC P2771 2016 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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P2771 2016 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 P2771 2016 GMC Sierra Code
1. What does the OBDII code P2771 mean on a 2016 GMC Sierra?
P2771 indicates an issue with the Four-Wheel Drive Low Switch Circuit, typically related to the vehicle's transfer case system.
2. What are the common symptoms of P2771 on a 2016 GMC Sierra?
Symptoms may include the 4WD Low mode not engaging, a check engine light, or unusual drivetrain performance.
3. What causes the P2771 code to appear on a 2016 GMC Sierra?
Common causes include a faulty 4WD low switch, damaged wiring, poor electrical connections, or a malfunctioning transfer case control module.
4. Can I still drive my 2016 GMC Sierra with a P2771 code?
While the vehicle may still be drivable, 4WD Low functionality will be compromised. Avoid situations requiring 4WD Low until the issue is resolved.
5. How do I diagnose the P2771 code in a 2016 GMC Sierra?
Start by scanning the vehicle with an OBDII scanner, inspecting the 4WD low switch and its wiring for damage, and testing the transfer case control module.
6. How can I fix the P2771 code on my 2016 GMC Sierra?
Repairs may include replacing the 4WD low switch, repairing or replacing damaged wiring, or addressing issues with the transfer case control module.
7. What tools are required to troubleshoot the P2771 code on a 2016 GMC Sierra?
You'll need an OBDII scanner, a multimeter for electrical testing, and basic hand tools for inspecting and replacing parts.
8. How much does it cost to repair a P2771 code on a 2016 GMC Sierra?
Repair costs can range from $100 to $500, depending on whether the issue is with the switch, wiring, or transfer case module.
9. Can a bad transfer case cause the P2771 code on a 2016 GMC Sierra?
Yes, a malfunctioning transfer case or its control module can trigger the P2771 code if it fails to communicate properly with the 4WD system.
10. Is the P2771 code a common issue on a 2016 GMC Sierra?
It’s not extremely common but can occur, especially in vehicles frequently used in off-road conditions or harsh environments.
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