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Tahoe / Yukon Service Manual

Side Blind Zone Alert System Malfunction

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. Diagnostic Fault Information

Circuit Number Circuit Function Short to Ground Open/High Resistance Short to Voltage Signal Performan
1760 Control 1 1 2 —
1761 Control 3 3 4 —
1150 Ground — 1 — —
1250 Ground — 3 — —
1.P34D Side Object Detection Indicator – Driver inoperative 2.P34D Side Object Detection Indicator – Driver always on 3.P34P Side Object Detection Indicator – Passenger inoperative 4.P34P Side Object Detection Indicator – Passenger always on

Circuit/System Description The side blind zone alert system helps alert drivers to avoid changing lanes when vehicles are detected in the side blind zone of the adjacent lane. The side blind zone alert system utilized two controls modules, the B218L Side Obstacle Detection Control Module – Left and the B218R Side Obstacle Detection Control Module – Right. Each B218  Side Obstacle Detection Control Module contains a radar and is located at the rear corner of the vehicle, behind the fascia. The B218L Side Obstacle Detection Control Module – Left and the B218R Side Obstacle Detection Control Module – Right communicate with one another on a private CAN bus and with the rest of the vehicle on CAN bus 4. The side blind zone alert systems uses the P34D Side Object Detection Indicator – Driver and P34P Side Object Detection Indicator – Passenger, located in the driver and passenger outside rearview mirror glass, to alert the driver to when vehicles are detected in the side blind zone of the adjacent lane. The B218L Side Obstacle Detection Control Module – Left and the B218R Side Obstacle Detection Control Module – Right will send a CAN message to the K9 Body Control Module when requesting the driver or passenger indicator be illuminated. The K9 Body Control Module then sends a LIN message to the S79D Front Side Door Window Control Switch - Driver or S79P Front Side Door Window Switch - Passenger with the indicator request. The S79D Front Side Door Window Control Switch - Driver or S79P Front Side Door Window Switch - Passenger will apply voltage to circuit 1760 or 1761 to illuminate the indicator. Each indicator receives a constant chassis ground on circuit 1150 or 1250. On vehicles equipped with Super Cruise (UKL), the B233SL Short Range Radar Rear Side Sensor - Left and B233RR Short Range Radar Rear Side Sensor - Right handle the side blind zone object detection in place of the B218L Side Obstacle Detection Control Module - Left and B218R Side Obstacle Detection Control Module - Right. Diagnostic Aids Side blind zone alert and lane change alert can be disabled in vehicle personalized settings. When disabled, the bulb check of the mirror indicators will also be disabled. A driver information center message will be displayed at start up when the system is disabled. Ensure the system is enabled before attempting to diagnose the system. The side blind zone alert system may be temporarily unavailable due to the following: A blockage condition exists (i.e. mud/snow buildup in front of the sensor). A driver information center message will be displayed at start up when the system is disabled. The side blind zone alert system transitions back to the normal operating state when the blockage is removed. Bumper stickers, fascia damage, labels, and heavy rain may also cause this condition. The blockage determination is performed with the vehicle in a drive gear. The side blind zone alert system will read the GPS latitude and longitude on the CAN bus and calculate if the vehicle is within a radio astronomy zone. These zones are located in the eastern U.S. at the Virginia and West Virginia border, Europe and Japan, and require the sensors to be turned off. A driver information center message will be displayed at start up when the system is disabled. The side blind zone alert system is designed to ignore stationary objects, however the system may occasionally detect guard rails, signs, trees, shrubs, or other stationary objects as an object in the blind zone. This is normal system operation and does not require service. The side blind zone alert system may indicate an object in the side blind zone if a trailer is attached to the vehicle, or a bicycle or object is extending out to either side of the vehicle. This is normal operation and does not require service. Reference Information Schematic Reference Driver Assistance Systems Schematics Connector End View Reference Master Electrical Component List Description and Operation Side Blind Zone Alert 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 Verification

  1. Ignition ON, verify both the P34D Side Object Detection Indicator – Driver and P34P Side Object Detection Indicator – Passenger briefly turn on during the system check and turn off after the check is complete. ⇒ If both the P34D Side Object Detection Indicator – Driver and P34P Side Object Detection Indicator – Passenger do not turn on or remain on at all times 1.1. Verify the system has not been disabled through vehicle personalization. ⇒ If the system is disabled through vehicle personalization, turn the system on and discuss with the customer the operation of the side blind zone alert system. ⇓ If the system is not disabled 1.2. Verify there are no DTCs set related to the side blind zone alert system. ⇒ If any DTCs are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle. ⇓ If no DTCs are set. 1.3. Refer to Diagnostic Aids to identify any normal operational limitations that may be related to the customer’s concern. ⇒ If only the P34D Side Object Detection Indicator – Driver does not turn on or remains on at all times Refer to Circuit/System Testing – Test 1 ⇒ If only the P34P Side Object Detection Indicator – Passenger does not turn on or remains on at all times Refer to Circuit/System Testing – Test 2 ⇓ If the P34D Side Object Detection Indicator – Driver and P34P Side Object Detection Indicator – Passenger turn on and off
  2. A fault is currently not present and may be an intermittent condition. Refer to Diagnostic Aids to identify any normal operational limitations that may be related to the customer’s concern. Circuit/System Testing Test 1
  3. Ignition OFF, disconnect the X1 connector at the S79D Front Side Door Window Control Switch
  • Driver, ignition ON.
  1. Verify the P34D Side Object Detection Indicator – Driver is not illuminated. ⇒ If the P34D Side Object Detection Indicator – Driver is illuminated Repair the short to voltage on circuit 1760. ⇓ If the P34D Side Object Detection Indicator – Driver is not illuminated
  2. Connect a 3 A fused jumper wire between control terminal 8 and B+.
  3. Verify the P34D Side Object Detection Indicator – Driver is illuminated. ⇒ If the P34D Side Object Detection Indicator – Driver is not illuminated 4.1. Test circuit 1150 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit or ground connection. ⇓ If an open/high resistance is not found 4.2. Test circuit 1760 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 4.3. Test circuit 1760 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 4.4. Replace the E17D Outside Rearview Mirror Glass – Driver. ⇓ If the P34D Side Object Detection Indicator – Driver is illuminated
  4. Replace the S79D Front Side Door Window Control Switch - Driver. Test 2
  5. Ignition OFF, disconnect the X1 connector at the S79P Front Side Door Window Control Switch - Passenger, ignition ON.
  6. Verify the P34P Side Object Detection Indicator – Passenger is not illuminated. ⇒ If the P34P Side Object Detection Indicator – Passenger is illuminated Repair the short to voltage on circuit 1761. ⇓ If the P34P Side Object Detection Indicator – Passenger is not illuminated
  7. Connect a 3 A fused jumper wire between control terminal 8 and B+.
  8. Verify the P34P Side Object Detection Indicator – Passenger is illuminated. ⇒ If the P34P Side Object Detection Indicator – Passenger is not illuminated 4.1. Test circuit 1250 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit or ground connection. ⇓ If an open/high resistance is not found 4.2. Test circuit 1761 for a short to ground. ⇒ If a short to ground is found, repair the fault on the circuit. ⇓ If a short to ground is not found 4.3. Test circuit 1761 for an open/high resistance. ⇒ If an open/high resistance is found, repair the fault on the circuit. ⇓ If an open/high resistance is not found 4.4. Replace the E17P Outside Rearview Mirror Glass – Passenger. ⇓ If the P34P Side Object Detection Indicator – Passenger is illuminated
  9. Replace the S79P Front Side Door Window Switch – Passenger. Repair Instructions Perform the Diagnostic Repair Verification after completing the repair. Driver Assistance Systems Component Replacement Reference Control Module References for control module replacement, programming, and setup.