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Home >> Cadillac >> 2013 >> SRX Base >> Repair and Diagnosis (Single Page) >> External Pages >> Different car >> Section 24 (Keyless Entry System And Remote Functions) >> Diagnostic Information and Procedures >> DTC B3120 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2010 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
    NOTE: The A24P passenger exterior door handle assembly has two harness connectors. Of these two harness connectors, make sure that only the T10N passenger door handle keyless entry antenna harness connector is disconnected. Disconnecting both harness connectors will result in the inability to activate the antenna and cause an improper diagnosis.
  1. Ignition OFF, disconnect the harness connector at the T10N passenger door handle keyless entry antenna.
  2. Ignition ON, test for less than 1 V between the signal circuit terminal 1 and ground.
    • If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K84 keyless entry control module.
  3. Ignition OFF, install a DMM between the signal circuit terminal 1 and ground. Set the DMM to capture DC voltage using the MIN MAX function.
  4. Lock the vehicle doors using the keyless entry transmitter.
  5. Activate the antenna by pulling the passenger exterior door handle. Verify the MAX voltage captured by the DMM is greater than .5 V.
    • If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K84 keyless entry control module.
  6. Install a DMM between the signal circuit terminal 1 and the low reference circuit terminal 2. Set the DMM to capture DC voltage using the MIN MAX function.
  7. Lock the vehicle doors using the keyless entry transmitter.
  8. Activate the antenna by pulling the passenger exterior door handle. Verify the MAX voltage captured by the DMM is greater than .5 V.
    • If less than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K84 keyless entry control module.
    9. NOTE: Install the A24P passenger exterior door handle assembly and verify correct system operation BEFORE painting the assembly. If the assembly does not correct the concern, return the unpainted part.
  9. If all circuits test normal, replace the A24P passenger exterior door handle assembly. Verify DTC B3120 is not set.
    • If the DTC is set, replace the K84 keyless entry control module.
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