P2771 2015 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 2015 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 2015 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 2015 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 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.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P2771 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 P2771 2015 GMC Sierra Code
1. What does the OBDII code P2771 mean on a 2015 GMC Sierra?
P2771 indicates an issue with the Four Wheel Drive (4WD) Low Switch Circuit, which signals a potential problem with the wiring, switch, or related components in the 4WD system.
2. What are the common symptoms of the P2771 code in a 2015 GMC Sierra?
Common symptoms include the 4WD system not engaging properly, the 4WD Low mode not working, and illumination of the check engine light or 4WD warning light.
3. What causes the P2771 code to appear?
Causes may include a faulty 4WD low switch, damaged or corroded wiring or connectors, or an issue with the transfer case control module.
4. Can I still drive my 2015 GMC Sierra with the P2771 code?
Yes, but you may not be able to use the 4WD Low feature, which can be problematic in off-road or low-traction conditions. It’s best to address the issue promptly.
5. How do I diagnose the P2771 code on a 2015 GMC Sierra?
Use an OBDII scanner to confirm the code, inspect the 4WD low switch, check for damaged wiring or loose connections, and test the transfer case control module.
6. What repairs are commonly needed to fix the P2771 code?
Repairs may include replacing the 4WD low switch, repairing or replacing damaged wiring or connectors, or reprogramming or replacing the transfer case control module.
7. How much does it cost to fix the P2771 code on a 2015 GMC Sierra?
Repair costs vary depending on the issue, but replacing the 4WD low switch typically costs $100–$300, while module repairs or wiring fixes may cost more.
8. Can a failing transfer case cause the P2771 code?
While rare, a failing or malfunctioning transfer case could potentially contribute to this code if it cannot properly engage 4WD Low.
9. Will clearing the P2771 code with a scanner fix the problem?
Clearing the code may temporarily reset the warning, but the underlying issue must be addressed to prevent the code from returning.
10. How can I prevent the P2771 code from occurring again?
Regularly inspect and maintain the 4WD system, including switches, wiring, and connectors, and address any issues as soon as they arise.
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