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Home >> Hummer >> 2008 >> H3 Alpha >> Repair and Diagnosis >> External Pages >> Different car >> Section 429 (Keyless Entry System And Remote Functions) >> Diagnostic Information and Procedures >> Key Fob Not Detected >> Circuit/System Verification
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Circuit/System Verification

WARNING: This page is about a different car, the 2009 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: This condition may be caused by low vehicle battery voltage. If the battery is not sufficiently charged (above 10 volts), the system will have difficulties detecting the fob and the NO FOB DETECTED message will be displayed. Correct the low battery voltage condition to eliminate this condition.
  1. Verify DTC B3119, B3120, B3121, B3122, or B3123 is not set.
  2. With the vehicle locked, attempt to passively unlock and enter the vehicle by approaching the vehicle with a valid transmitter and pulling the exterior door handle. The door should unlock and open.
  3. Place the transmitter in the console active antenna pocket and attempt to start the vehicle. The vehicle should start.
  4. While placing the keyless entry transmitter in various locations within the vehicle interior, attempt to start the vehicle. The NO FOB DETECTED message should be displayed on the DIC.
    • If the message is not displayed, inspect for any sources of RF interference such as cell phone chargers, power supplies, etc. that would interrupt transmitter and antenna communication. If inspect does not reveal any items causing RF interference, contact the customer and question the customer about the conditions or location where the NO FOB DETECTED condition occurs. Discuss any devices that are normally kept in the vehicle, such as a laptop or cell phone charger, which may have been removed when the vehicle was brought in for service. It may be necessary to explain to the customer how RF interference degrades the performance of the system.