B154B 2018 GMC Sierra 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 2018 GMC Sierra 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 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 passenger window switch while commanding the passenger outside rearview mirror UP, DOWN, LEFT, or RIGHT.
What are the Possible Causes of the DTC B154B 2018 GMC Sierra?
- 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 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 B154B 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 B154B 2018 GMC Sierra Code
1. What does OBDII code B154B mean on a 2018 GMC Sierra?
Code B154B indicates a "Passenger Mirror Internal Malfunction," meaning there is an issue with the internal components or circuitry of the passenger-side mirror.
2. What are the symptoms of code B154B in a 2018 GMC Sierra?
Common symptoms include the passenger-side mirror not adjusting properly, mirror heating not functioning, or mirror folding/unfolding failing.
3. What causes the B154B code to appear on a 2018 GMC Sierra?
This code is often caused by a faulty mirror motor, damaged wiring, loose connections, or an issue with the mirror control module.
4. Can I still drive my 2018 GMC Sierra with a B154B code?
Yes, the vehicle is still drivable, but the passenger mirror may not function correctly, which could reduce visibility and safety.
5. How do I diagnose the B154B code on my 2018 GMC Sierra?
Diagnosis involves checking for physical damage to the mirror, inspecting wiring and connectors for corrosion or breaks, and using a scan tool to test the mirror control module.
6. Is the passenger mirror the only affected part with a B154B code?
Yes, this code specifically pertains to the passenger-side mirror and does not affect other vehicle systems.
7. How can I fix the B154B code on a 2018 GMC Sierra?
Repairs may include replacing the passenger mirror assembly, repairing damaged wiring, or resetting the mirror control module.
8. Does the B154B code require a software update on the 2018 GMC Sierra?
While not typical, some cases may require a software update for the mirror control module if hardware issues are ruled out.
9. How much does it cost to repair the B154B code on a GMC Sierra?
Repair costs vary depending on the issue, ranging from $100 to $500 for parts and labor, with mirror assembly replacement being the most expensive.
10. Can I clear the B154B code without fixing the issue?
Clearing the code without fixing the underlying problem is not recommended, as the issue will likely return and could compromise safety.
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