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Tahoe / Yukon Service Manual

DTC B1444

Diagnostic Instructions Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Review Strategy Based Diagnosis for an overview of the diagnostic approach. Diagnostic Procedure Instructions provides an overview of each diagnostic category. DTC Descriptors Passive Start Interior Antenna 2 Signal Hi For symptom byte information, refer to Symptom Byte List. Diagnostic Fault Information

Circuit Number Circuit Short to Ground Open/Hi Resistan Short gh to ceVoltage Signal Performa
3552 Passive Start Interior Antenna 2 Signal Hi — High Reference B1444 11 B1444 13 B1444 12 —
3553 Passive Start Interior Antenna 2 Signal Hi — Low Reference B1444 11 B1444 13 B1444 12 —

Circuit/System Description The passive start interior antenna 2 is located inside of the rear of the center console and is used to establish low frequency communications with the keyless entry transmitter. As the ignition switch is pressed the BCM will transmit low frequency signals to this interior keyless entry antenna 2. Diagnostic Aids The antenna must be installed correctly for proper performance. The precise location and orientation are important for the antenna to have the range and shape of range designed for each antenna location. There is a possibility that the passive entry system set a false DTC due to the antenna being incorrectly installed. Conditions for Running the DTC The ignition switch is pressed or all the doors are closed. Conditions for Setting the DTC B1444 11 The body control module detects a short to ground on the passive start interior antenna 2 signal circuit three or more times. B1444 12 The body control module detects a short to voltage on the passive start interior antenna 2 signal circuit three or more times. B1444 13 The body control module detects an open on the passive start interior antenna signal 2 circuit three or more times. Action Taken When the DTC Sets Doors will not unlock/lock when the exterior door handle button is pressed. Reduced or no coverage of the keyless entry transmitter inside the vehicle when the ignition switch is pressed or all doors are closed. The service keyless start system message will display in the DIC. Conditions for Clearing the DTC A current DTC will clear when the conditions for setting the DTC are no longer present. A history DTC will clear after 50 malfunction-free ignition cycles. Reference Information Schematic Reference Remote Function Schematics Connector End View Reference Master Electrical Component List Description and Operation Keyless Entry System Description and Operation Electrical Information Reference Circuit Testing Connector Repairs Testing for Intermittent Conditions and Poor Connections Wiring Repairs Scan Tool Reference Control Module References for scan tool information Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the T10K Keyless Entry Antenna — Center Console Rear, ignition ON.
  2. Test for less than 1 V between the signal circuit terminal 1 and ground. ⇒ If 1 V or greater 2.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. 2.2. Test for less than 1 V between the signal circuit and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module. ⇓ If less than 1 V
  1. 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. Turn off autorange and manually set the DMM range to 000.0 V.
  2. Activate the antenna by pressing the Stop/Start switch.
  3. Verify the MAX voltage captured by the DMM is greater than 1 V. ⇒ If 1 V or less 5.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module. 5.2. Test for infinite resistance between the signal circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 5.3. Test for less than 2 Ω in the signal circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module. ⇓ If greater than 1 V
  4. Test for less than 1 V between the low reference circuit terminal 2 and ground. ⇒ If 1 V or greater 6.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module, ignition ON. 6.2. Test for less than 1 V between the low reference circuit and ground. ⇒ If 1 V or greater, repair the short to voltage on the circuit. ⇒ If less than 1 V, replace the K9 Body Control Module. ⇓ If less than 1 V
  1. 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. Turn off autorange and manually set the DMM range to 000.0 V.
  2. Activate the antenna by pressing the Stop/Start switch.
  3. Verify the MAX voltage captured by the DMM is greater than 1 V. ⇒ If 1 V or less 9.1. Ignition OFF, disconnect the harness connector at the K9 Body Control Module. 9.2. Test for infinite resistance between the low reference circuit and ground. ⇒ If less than infinite resistance, repair the short to ground on the circuit. ⇓ If infinite resistance 9.3. Test for less than 2 Ω in the low reference circuit end to end. ⇒ If 2 Ω or greater, repair the open/high resistance in the circuit. ⇒ If less than 2 Ω, replace the K9 Body Control Module. ⇓ If greater than 1 V
  4. Replace the T10K Keyless Entry Antenna — Center Console Rear.
  5. Activate the antenna by pressing the Stop/Start switch a minimum of three times to meet the conditions for setting the DTC.
  6. Verify DTC B1444 is not set. ⇒ If DTC B1444 is set Replace the K9 Body Control Module. ⇓ If DTC B1444 is not set
  7. All OK. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Low Frequency Console Antenna Replacement Control Module References for keyless entry control module replacement, programming, and setup