Buick Regal: Rain Sensor 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/System Description
B+ and ground is supplied at all times to the rain sensor. The rain sensor
communicates with the body control
module (BCM) via serial data. When the ignition is in the ON or ACCESSORY
position and the windshield
wiper/washer switch is in the intermittent delay position, the BCM monitors the
rain sensor data to determine the
rain build up on the windshield. As rain builds up on the windshield, the BCM
will command the wipers to activate.
The sensitivity of the wiper frequency is controlled by the intermittent delay
of the windshield wiper/washer switch.
As the sensitivity is increased, the BCM will command more frequent wiper
activation based on rain build up on the
windshield.
Reference Information
Schematic Reference
Wiper/Washer Wiring Schematics
Connector End View Reference
COMPONENT CONNECTOR END VIEWS - INDEX
Description and Operation
Wiper/Washer 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 Verification
1. Ignition ON.
2. Verify DTC U151A is not set.
Refer to DTC U1500-U15FF
- Go to next step: If the DTC is not set
3. Place the S82 Windshield Wiper/Washer Switch in the intermittent delay
setting and spray the outside of the
windshield in the area of the B177 Rain Sensor with a water bottle. It may be
necessary to increase the
sensitivity of the intermittent delay to achieve windshield wiper operation.
4. Verify the windshield wipers operate at low speed.
- If the wipers are not operating at low speed
Refer to Circuit/System Testing.
- Go to next step: If the wipers are operating at low speed
5. All OK.
Circuit/System Testing
1. Ignition OFF, all vehicle systems OFF, disconnect the harness connector at
the B117 Rain Sensor. It may take
up to 2 min for all vehicle systems to power down.
2. Test for less than 10 Ω between the ground circuit terminal 3 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. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
- Ignition OFF, remove the test lamp.
- 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, remove the test lamp.
- 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 B117 Rain Sensor.
- Go to next step: If the test lamp illuminates
5. Test for 5.0 - 10.0 V between the serial data circuit terminal 2 and
ground.
- Ignition OFF, disconnect the harness connector at the K9 Body Control
Module.
- Test for infinite resistance between the serial data circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- Go to next step: If infinite resistance
- Test for less than 2 Ω in the serial data 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.
- Ignition OFF, disconnect the harness connector at the K9 Body Control
Module, ignition ON.
- Test for less than 1 V between the serial data 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.
- Go to next step: If between 5.0 - 10.0 V
6. Test or replace the B117 Rain Sensor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Inside Air Moisture and Windshield Temperature Sensor Replacement
- Control Module References for BCM replacement, programming and setup
READ NEXT:
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 - 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 - Vehicle prior to using this
diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic
approach.
Diag
SEE MORE:
1. Raise and support the vehicle.
2. Clean the area around the rear axle fill plug.
3. Place a drain pan under the vehicle.
4.
Differential Clutch Cover Plug(1) - Remove.
5. Rear Axle Housing Filler Plug Gasket(2) - Remove.
6. Check the fluid level. If necessary, fill the differential to the
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
D