B154B GMC Code - Passenger 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 Passenger Outside Rearview Mirror Motor, Passenger Outside Rearview Mirror Motor harness is open or shorted, Passenger 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
- B154B GMC indicates Passenger Mirror Internal Malfunction.
- Common causes
- Common causes include Faulty Passenger Outside Rearview Mirror Motor, Passenger Outside Rearview Mirror Motor harness is open or shorted, Passenger 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 B154B GMC 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 passenger window switch while commanding the passenger outside rearview mirror UP, DOWN, LEFT, or RIGHT.
What are the Possible Causes of the DTC B154B GMC?
- Faulty Passenger Outside Rearview Mirror Motor
- Passenger Outside Rearview Mirror Motor harness is open or shorted
- Passenger Outside Rearview Mirror Motor circuit poor electrical connection
How to Fix the DTC B154B GMC?
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 B154B GMC 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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Information for Specific GMC Models
- B154B 2014 GMC Sierra — Passenger Mirror Internal Malfunction
- B154B 2015 GMC Sierra — Passenger Mirror Internal Malfunction
- B154B 2016 GMC Sierra — Passenger Mirror Internal Malfunction
- B154B 2017 GMC Sierra — Passenger Mirror Internal Malfunction
- B154B 2018 GMC Sierra — Passenger Mirror Internal Malfunction
Frequently Asked Questions about B154B GMC Code
1. What does the OBDII code B154B mean on a GMC vehicle?
The code B154B indicates a "Passenger Mirror Internal Malfunction," meaning there is an issue with the internal electronics or motor of the passenger side mirror.
2. What are common symptoms of the B154B code on a GMC?
Symptoms may include the passenger side mirror not adjusting correctly, unresponsive mirror controls, or the mirror heating function not working.
3. What causes the B154B code to appear on a GMC?
The code can be caused by a faulty mirror motor, damaged internal wiring, a defective mirror control module, or a poor connection to the mirror assembly.
4. Can a blown fuse trigger the B154B code on my GMC?
Yes, a blown fuse related to the mirror system could potentially disrupt power and trigger this code, though it is less common.
5. How is the B154B code diagnosed in a GMC vehicle?
A technician will use a scan tool to confirm the code, inspect the mirror assembly, check for damaged wiring, and test the mirror control module for proper functionality.
6. Can I still drive my GMC with the B154B code active?
Yes, the code does not affect drivability, but the passenger side mirror may not function properly, which could impact visibility and safety.
7. How do I fix the B154B code on my GMC?
Repairs may include replacing the passenger side mirror assembly, repairing damaged wiring, or replacing the mirror control module if it is faulty.
8. How much does it cost to repair a B154B code issue on a GMC?
Repair costs vary depending on the issue but typically range from $150 to $500, including parts and labor, for a mirror assembly replacement.
9. Can I clear the B154B code without fixing the issue?
You can clear the code using a scan tool, but it will likely return if the underlying problem is not resolved.
10. Is the B154B code covered under warranty for my GMC?
It depends on your vehicle’s warranty. If the issue involves defective parts within the warranty period, it may be covered by the manufacturer.
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