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2023 S90 Key Fob Not Detected - Passive Entry Issues

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Mike T. · rep 0 · May 25, 3:55 AM · 1 replies · solved · Question

Vehicle: 2023 Volvo S90 T8 Recharge

My 2023 Volvo S90 T8 Recharge is having intermittent issues detecting the key fob. Sometimes I can't unlock the doors using passive entry, and then when I get in, I get a "Key Fob Not Detected" message on the dash, preventing me from starting the car.

I've replaced the battery in the key fob, and it still happens. It's really frustrating, especially when I'm in a hurry. Could this be an antenna issue in the car, or perhaps a module problem? The spare key fob has the same problem.

✓ Accepted solution

ClearTheCode Admin

ClearTheCode Team · rep 0 · May 25, 3:55 AM

0

ClearTheCode admin answer:

  1. Key Fob Battery (Double Check): Even though you've replaced it, ensure the new battery is fresh (not old stock) and inserted correctly with the proper polarity. A weak key fob battery is the most common culprit. Try both key fobs to see if the issue is isolated to one.
  2. Interference: External radio frequency interference can sometimes block the signal between the key fob and the car. This can happen in certain locations (e.g., near strong radio transmitters, cell towers, or even other electronic devices in your pocket/bag). Try moving the key fob to different locations inside the car to see if detection improves.
  3. Vehicle Antenna System: Modern Volvos use multiple antennas located throughout the vehicle (e.g., in the center console, trunk, roof) to detect the key fob's presence for passive entry and starting. A fault in one of these antennas or their wiring can cause intermittent detection issues.
  4. Keyless Entry Module (KEM) / Central Electronic Module (CEM): The Keyless Entry Module or the Central Electronic Module (CEM) is responsible for processing the key fob's signal. A fault within these modules could lead to the symptoms you're experiencing.
  5. Software Glitch: Like many advanced electronic systems, a software glitch in the vehicle's keyless entry system could be causing the problem. A software update from a Volvo dealership might resolve this.
  6. Diagnostic Scan: A professional diagnostic scan using Volvo's VIDA system is essential. It can reveal specific fault codes related to the keyless entry system, antenna faults, or communication issues between modules. Look for codes like B1A55 (Key Fob Transponder Malfunction), B1A56 (Key Fob Signal Not Received), or U-codes related to communication with the KEM or CEM.
  7. When to See a Shop: Since you've tried a new key fob battery and the issue affects both fobs intermittently, it strongly suggests a vehicle-side problem rather than the fob itself. It's best to schedule an appointment with a Volvo dealership. They have the specialized tools and expertise to diagnose the keyless entry system, test antenna functionality, and check for module faults or necessary software updates.
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