Buick Regal: Rear Cross Traffic 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
1. Rear Cross Traffic Alert Malfunction
Circuit/System Description
The side object sensor modules are located on each side of the vehicle behind
the rear fascia and are not
directly visible from outside the vehicle. The same sensors are also used for
side blind zone alert. The
sensors use radar to determine the presence of objects near the back of the
vehicle. When an object is
detected in the rear cross traffic zone, the module will send out a signal
through serial data
communication to turn on the visual icons and also audio chime or haptic
notification. Each sensor is
supplied B+ and ground. The right sensor receives an additional ground. Both
sensors communicate
independently on the serial data line. The serial data enters the left sensor in
a pass-thru configuration,
that connects to the right sensor. The scan tool is able to individually
communicate with each sensor.
Diagnostic Aids
- The rear cross traffic alert system uses the same sensors as side blind
zone alert so a malfunction
may affect either or both systems.
- The conditions for disabling the rear cross traffic alert system are
captured by DTCs. The drivers
information center will display Service Side Detection System if one of the
sensors has failed. A
B101E 47 Electronic Control Unit Software VIN Not Programmed DTC in history
will not affect
sensor operation and the module should not be replaced for this DTC.
- The rear cross traffic system can be disabled if any off the following
occur:
- The driver has selected the Off mode through vehicle personalization
menus. The selected
mode is retained over ignition cycles. A driver information center
message stating that the
Rear Cross Traffic System Alert Off shall be displayed.
- There is a loss of serial data communication with a sensor or
between modules.
- The side blind zone 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 message "Side Detection System Unavailable" will be
displayed. The side blind
zone system transitions back to the normal operating state when the
blockage is removed.
Bumper sticks, fascia damage, labels, and heavy rain storms may also
cause this condition.
The blockage determination is performed with the vehicle in a drive
gear.
- The rear cross traffic alert system will read the GPS latitude and
longitude on the serial data
bus and calculate if the vehicle is within a Radio Astronomy zone. These
zones are located
in Europe and Japan and require the sensors to be turned off. The "Side
Detection System
Unavailable" message will be displayed to the driver when this occurs.
- Because the sensors are identical, they may be swapped from one side of
the vehicle to the other
in an attempt to isolate a concern. Sensors should NOT be swapped from one
vehicle to another.
- The rear cross traffic alert system is designed to ignore stationary
objects; however, the system
may occasionally detect pedestrians, shopping carts, or other objects. This
is normal system operation and does not require service.
- The rear cross traffic alert system may indicate an object 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 Wiring Schematics
Connector End View Reference
Master Electrical Component List
Description and Operation
Cross Traffic 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.
2. Verify that no DTCs are set.
Refer to: Diagnostic Trouble Code (DTC) List - Vehicle
- Go to next step: If no DTC is set
3. Verify the scan tool can communicate with the left side object sensor.
- If the scan tool can not communicate with the left side object sensor
Refer to Circuit/System Testing - Left Side Object Sensor Malfunction.
- Go to next step: If the scan tool can communicate with the left side
object sensor
4. Verify the scan tool can communicate with the right side object sensor.
- If the scan tool can not communicate with the right side object
sensor
Refer to Circuit/System Testing - Right Side Object Sensor Malfunction.
- Go to next step: If the scan tool can communicate with the right side
object sensor
5. Verify that the rear cross traffic indicators turn ON and then turn OFF
when commanding the Rear
Cross Traffic Visual Alert Indicators ON and OFF with a scan tool.
- If alert indicators do not turn ON and OFF
- Verify the system is enabled.
- If disabled, refer to diagnostic aids for cause of disable.
- If enabled test or replace the display.
- Go to next step: If indicators turn ON and OFF
6. Verify that the audible alert turns ON and then turn OFF when commanding
the Rear Cross Traffic
Audible Alert ON and OFF with a scan tool.
- If the audible alert does not turn ON and OFF
- Verify the system is enabled.
- If disabled, refer to diagnostic aids for cause of disable.
- If enabled refer to audio system malfunction.
- Go to next step: If audible alert turns ON and OFF
7. All OK.
Circuit/System Testing
Left Side Object Sensor Malfunction
1. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for
all vehicle systems to
power down. Disconnect the harness connector at the B218L Side Object Sensor
Module - Left.
2. Test for less than 10 Ω between ground circuit terminal 7 and ground.
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If less than 10 Ω
3. Verify a test lamp illuminates between the B+ circuit terminal 8 and
ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition Off.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage
at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, replace the B218L Side Object Sensor Module
- Left.
- Go to next step: If the test lamp illuminates
4. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for
all vehicle systems to
power down.
5. Test for less than 2 Ω in each of the serial data circuits end to end between
the control module
harness connector terminal 2 and the DLC terminal 1.
Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
6. Replace B218L Side Object Sensor Module - Left.
Right Side Object Sensor Malfunction
1. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for
all vehicle systems to
power down. Disconnect the harness connector at the B218R Side Object Sensor
Module - Right.
2. Test for less than 10 Ω between the following ground circuit terminals and
ground.
- Terminal 3
- Terminal 8
- If 10 Ω or greater
- Ignition OFF.
- Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground
connection.
- Go to next step: If less than 10 Ω
3. Verify a test lamp illuminates between the B+ circuit terminal 5 and
ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF.
- Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage
at the fuse.
- If the test lamp does not illuminate and the circuit fuse is open
- Ignition OFF.
- Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance, replace the B218R Side Object Sensor Module
- Right.
- Go to next step: If the test lamp illuminates
4. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for
all vehicle systems to
power down.
5. Test for less than 2 Ω in each of the serial data circuits end to end between
the control module
harness connector terminal 7 and the DLC terminal 1.
Repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω
6. Replace B218R Side Object Sensor Module - Right.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for control module replacement, programming and
setup.
READ NEXT:
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strate
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.
Diag
Diagnostic Instructions
Perform the Diagnostic System Check prior to using this diagnostic
procedure: Diagnostic
System Check - Vehicle
Review the description of Strategy Based Diagnosis: Strate
SEE MORE:
Scrapping Procedure
During the course of a vehicles useful life, certain situations may arise
which will necessitate the disposal of a
live (undeployed) pretensioner. The following information covers the proper
procedures for the disposing of a
live (undeployed) pretensioner. Deploy the pretension
Premium Recommended Fuel
Use premium 93 octane unleaded
gasoline in your vehicle. Unleaded
gasoline with an octane rating as
low as 87 may be used, but it will
reduce performance and fuel
economy.
Fuel (3.6L Engine)
Regular Fuel
Use only unleaded gasoline rated
87 octane or higher in your vehicle.