AutoCodes – GMC – B0770 2015 GMC Sierra

B0770 2015 GMC Sierra Code - All Wheel Drive Indicator Circuit

Quick Answer

The All Wheel Drive (AWD/4WD Auto) indicator circuit consists of a Light Emitting Diode (LED) feed circuit, a LED, and a LED control circuit. Common causes include Faulty Transfer Case Select Switch, Transfer Case Select Switch harness is open or shorted, Transfer Case Select Switch circuit poor electrical connection. Severity is Moderate - service should be scheduled soon. The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

What it means: B0770 2015 GMC Sierra indicates All Wheel Drive Indicator Circuit.
Common causes: Common causes include Faulty Transfer Case Select Switch, Transfer Case Select Switch harness is open or shorted, Transfer Case Select Switch circuit poor electrical connection.
Severity: Moderate - service should be scheduled soon.
Can I drive?: The vehicle may still be drivable for short trips if it runs normally, but avoid hard driving and repair it soon.

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Code Popularity 299

How popular is this code, among other codes? Low

Repair Importance Level

Moderate (Service soon) (2 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Nov 18, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B0770 2015 GMC Sierra Description

The All Wheel Drive (AWD/4WD Auto) indicator circuit consists of a Light Emitting Diode (LED) feed circuit, a LED, and a LED control circuit. The indicator dimming control circuit is the LED feed circuit and continuously supplies B+ to the 2WD HI, 4WD Auto, 4WD HI, and 4WD LO LEDs. When the AWD mode has been selected by the driver, the transfer case shift control module (TCCM) provides a ground through the AWD indicator control circuit illuminating the LED.
The TCCM tests the AWD indicator circuit for unexpected voltage by monitoring the B+ supplied by the BCM on the indicator dimming control circuit by grounding the AWD indicator control circuit for 2 seconds during the Bulb Test at key ON.

OBDII Code B0770 2015 GMC Sierra - All Wheel Drive Indicator Circuit - AutoCodes.com — B0770 2015 GMC Sierra Code - All Wheel Drive Indicator Circuit

What does this mean?

What are the Possible Causes of the DTC B0770 2015 GMC Sierra?

Faulty Transfer Case Select Switch
Transfer Case Select Switch harness is open or shorted
Transfer Case Select Switch circuit poor electrical connection
Faulty Transfer Case Shift Control Module (TCCM)

How to Fix the DTC B0770 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 B0770 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.

Need more information about the B0770 2015 GMC Sierra code?

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About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B0770 2015 GMC Sierra Code

1. What does the OBDII code B0770 mean on a 2015 GMC Sierra?

The code B0770 indicates an issue with the All Wheel Drive (AWD) Indicator Circuit, which is responsible for displaying the AWD status on the dashboard.

2. What are the common symptoms of the B0770 code on a 2015 GMC Sierra?

Symptoms may include the AWD indicator not illuminating, staying on constantly, or flashing unexpectedly, along with potential AWD system malfunctions.

3. What causes the B0770 code on a 2015 GMC Sierra?

Common causes include a faulty AWD indicator bulb or LED, damaged wiring or connectors in the AWD circuit, or a malfunctioning transfer case control module (TCCM).

4. Can the B0770 code affect the AWD system's performance?

Yes, in some cases, this code may indicate underlying issues in the AWD system that could affect its ability to engage or operate properly.

5. How can I diagnose the B0770 code on my GMC Sierra?

Start by inspecting the AWD indicator bulb or LED, checking for damaged wiring or loose connections, and scanning the transfer case control module for additional codes.

6. Is the B0770 code safe to ignore?

No, ignoring this code could lead to further AWD system issues or leave you unaware of AWD system functionality, especially in adverse driving conditions.

7. How do I fix the B0770 code on a 2015 GMC Sierra?

Repairs may include replacing a faulty AWD indicator bulb or LED, repairing or replacing damaged wiring, or reprogramming or replacing the transfer case control module.

8. Can a dead battery cause the B0770 code to appear?

A weak or dead battery can result in electrical issues, including this code, if it causes a disruption in the AWD indicator circuit.

9. How much does it cost to repair the B0770 code on a GMC Sierra?

Repair costs vary depending on the issue but typically range from $100-$300 for wiring repairs or bulb replacement, and up to $600 or more if the TCCM needs replacement.

10. Can I clear the B0770 code without fixing the problem?

You can clear the code temporarily with an OBDII scanner, but it will likely reappear unless the underlying issue is resolved.