B10A1 Code and Keyless Go Not Responding - 2016 Mercedes GL450

Question

My GL450 is throwing code B10A1 and I am getting intermittent issues where the Keyless Go feature won't unlock the doors when touching the handle. Sometimes the push-button start tells me the key is not detected even though it is in my pocket. Once I get it started, the car runs fine but the diagnostic scan shows this permanent fault in the Electronic Ignition Switch (EIS) module.

Tom Patel · Accepted Answer

The issue was the quality of the replacement battery. I had used a generic brand; I switched to a high-quality Panasonic CR2025 and ensured it measured 3.2V before installing. I also used a flathead to slightly bend the contact pins upward to provide more tension. After clearing the codes with my Xentry tool, the Keyless Go started working every time and the B10A1 code stayed gone.

Jake Morrison · Answer

Check the voltage on the 'new' battery you installed. Those pharmacy packs sometimes sit on the shelf for years and Benz fobs are extremely sensitive to voltage drops below 3.0V.

fleet_chief_42 · Answer

You might need to clean the battery contacts inside the key fob. Use a Q-tip with a tiny bit of isopropyl alcohol and make sure the metal tabs are actually making firm contact with the CR2025 cell.

Lina Brooks · Answer

The B10A1 can sometimes be a false positive if your main vehicle battery (the one under the passenger seat) is getting weak. Low system voltage during cranking can cause various modules like the EIS to throw weird communication and key codes.

B10A1 Code and Keyless Go Not Responding - 2016 Mercedes GL450

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