B154A 2018 GMC Sierra Code - Driver Mirror Internal Malfunction
Quick Answer
The outside mirror switch and passenger window switch are on a serial data circuit with the memory seat module as the master. Common causes include Faulty Driver Outside Rearview Mirror Motor, Driver Outside Rearview Mirror Motor harness is open or shorted, Driver Outside Rearview Mirror Motor 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
- B154A 2018 GMC Sierra indicates Driver Mirror Internal Malfunction.
- Common causes
- Common causes include Faulty Driver Outside Rearview Mirror Motor, Driver Outside Rearview Mirror Motor harness is open or shorted, Driver Outside Rearview Mirror Motor 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 B154A 2018 GMC Sierra Description
Mirror position is determined by both horizontal and vertical position sensors in each of the power mirrors. The outside mirror switch and passenger window switch supply a 5 V reference, low reference, and horizontal and vertical position signal circuits to these sensors. The signal circuits are referenced from 5 V by the switches and the signal circuit voltage levels represent the mirror positions. The mirror positions are sent to the memory seat module through the serial data circuit where they are stored for memory mirror operation. When the memory seat module receives a memory recall command, the memory seat module will send the go to position commands to the outside mirror switch and passenger window switch. The switches will then drive the appropriate mirror motors to the commanded position sensor settings.
The Diagnostic Trouble Code (DTC) will be set when an internal malfunction has been detected by the outside rearview mirror switch while commanding the driver outside rearview mirror UP, DOWN, LEFT, or RIGHT.
What are the Possible Causes of the DTC B154A 2018 GMC Sierra?
- Faulty Driver Outside Rearview Mirror Motor
- Driver Outside Rearview Mirror Motor harness is open or shorted
- Driver Outside Rearview Mirror Motor circuit poor electrical connection
How to Fix the DTC B154A 2018 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 B154A 2018 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 B154A 2018 GMC Sierra Code
1. What does the OBDII code B154A mean on a 2018 GMC Sierra?
B154A indicates a Driver Mirror Internal Malfunction, typically pointing to an electrical or functional issue within the driver-side mirror assembly.
2. What are the common symptoms of code B154A on a 2018 GMC Sierra?
Symptoms include the driver-side mirror not adjusting properly, loss of auto-dimming or heating functions, or the mirror becoming unresponsive.
3. What causes the B154A code in a 2018 GMC Sierra?
Common causes include a faulty driver-side mirror motor, damaged wiring or connectors, or an issue with the mirror control module.
4. Can a blown fuse cause the B154A code?
Yes, a blown fuse related to the mirror system can lead to a loss of power and trigger this code.
5. How do I diagnose the B154A code on my GMC Sierra?
Start by inspecting the mirror wiring and connectors for damage, testing the mirror motor, and checking for power and ground at the mirror's electrical connection.
6. Can the B154A code cause other electrical issues?
While typically isolated to the mirror system, it could indicate broader wiring or module issues if multiple components are affected.
7. Does the B154A code mean I need to replace the entire driver-side mirror?
Not always. The issue could be resolved by repairing wiring or replacing specific components like the mirror motor or control module.
8. How much does it cost to fix the B154A code on a 2018 GMC Sierra?
Repair costs vary, but replacing a driver-side mirror assembly can cost $200–$500, while repairing wiring or connectors may be less expensive.
9. Can I still drive my GMC Sierra with the B154A code?
Yes, it's safe to drive, but limited mirror functionality may impact visibility and convenience.
10. How do I clear the B154A code after repairs?
Use an OBDII scanner to clear the code, but ensure the issue is resolved to prevent the code from returning.
Discuss the causes and fixes for B154A 2018 GMC Sierra OBDII Code
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