Chevrolet Trax: DTC B370B: Rear wiper function control circuit
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 Descriptor
DTC B370B
Rear Wiper Function Control Circuit
For symptom byte information, refer to Symptom Byte List .
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) controls the rear wiper motor based on an input
from the rear wiper switch,
which is part of the windshield wiper/washer switch. The BCM monitors the
windshield wiper/washer switch
through two separate signal circuits and a low reference circuit. The rear wiper
switch uses a resistor ladder to
determine low speed, intermittent, and rear washer operation. The BCM monitors
applies and monitors voltage
on the rear wiper switch signal circuit. When the rear wiper switch is placed in
the low speed, intermittent, or
rear washer position, the voltage is pulled down through a different resistor in
the resistor ladder, reducing the
voltage seen at the BCM. The BCM will respond by commanding the specific rear
wiper function.
The rear wiper motor is controlled by the BCM through the rear wiper relay. A
constant B+ and ground are
supplied to the rear wiper motor. When rear wiper operation is requested, the
BCM will apply voltage to the
rear wiper relay control circuit. This will cause the contacts in the rear wiper
relay to close and apply B+ to the
rear wiper motor through the rear wiper control circuit, enabling rear wiper
operation. When the rear wiper
request is no longer present, the contacts in the rear wiper relay will open,
removing B+ from the rear wiper
motor control circuit. The rear wiper motor will continue to operate using the
constant B+ circuit until it is in
the park position.
Conditions for Running the DTC
- Ignition ON
- The system voltage is between 9-16 V.
Conditions for Setting the DTC
B370B 01
A short to voltage is detected in the rear wiper relay control circuit.
B370B 02
A short to ground is detected in the rear wiper relay control circuit.
B370B 04
An open or high resistance is detected in the rear wiper relay control
circuit.
Action Taken When the DTC Sets
Rear wiper operation is disabled.
Conditions for Clearing the DTC
The DTC will clear when the conditions for setting the DTC are no longer
present.
Reference Information
Schematic Reference
Wiper/Washer Schematics (Encore), Wiper/Washer Schematics (Trax)
Connector End View Reference
WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS -
INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT
CONNECTOR END VIEWS - INDEX - TRAX
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
- Ignition ON.
- Verify the scan tool Rear Closure Ajar Switch parameter changes between
Inactive and Active when
opening and closing the liftgate.
If the parameter does not change
Refer to Door Ajar Indicator Malfunction
If the parameter changes
- Verify the Scan Tool Rear Wiper Switch Parameter changes between ON and
OFF when cycling the rear
wiper switch ON and OFF.
- If the parameter does not change
- Refer to Circuit/System Testing - Rear Wiper/Washer Switch Malfunction
If the parameter changes
- Verify the M45 Rear Wiper Motor cycles when commanding the rear wiper ON
with the rear wiper
switch
If the M45 Rear Wiper Motor does not cycle
Refer to Refer to Circuit/System Testing - Rear Wiper Motor Malfunction
If the M45 Rear Wiper Motor cycles
- Verify the M45 Rear Wiper Motor returns to the park position when the
rear wipers are turned OFF
If the M45 Rear Wiper Motor does not return to the park position
Refer to Circuit/System Testing - Rear Wiper Motor Malfunction
If the M45 Rear Wiper Motor returns to the park position
- All OK.
Circuit/System Testing
Rear Wiper/Washer Switch Malfunction
- Ignition OFF and all vehicle systems OFF, disconnect the harness
connector at the S82 Windshield
Wiper/Washer Switch. It may take up to 11 min for all vehicle systems to
power down.
- Test for less than 10 ohms between the low reference circuit terminal 2
and ground.
If 10 ohms or greater
- Ignition OFF.
- Test for less than 2 ohms in the low reference circuit end to end.
- If 2 ohms or greater, repair the open/high resistance in the circuit.
- If less than 2 ohms, replace the K9 Body Control Module.
If less than 10 ohms
- Ignition ON.
- Test for greater than 8 V between the signal circuit terminal 4 and
ground.
If less than 8 V
- Ignition OFF, disconnect the harness connector at the K9 Body Control
Module.
- 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
- Test for less than 2 ohms in the signal circuit end to end.
- If 2 ohms or greater, repair the open/high resistance in the circuit.
- If less than 2 ohms, replace the K9 Body Control Module.
If 8 V or greater
- Ignition OFF, disconnect the X2 harness connector at the K9 Body Control
Module, ignition ON.
- Test for less than 1 V between the S82 Windshield Wiper/Washer Switch
signal circuit terminal 4 and
ground.
If 1 V or greater
Repair the short to voltage on the circuit.
If less than 1 V
- Test or replace the S82 Windshield Wiper/Washer Switch.
Rear Wiper Motor Malfunction
- Ignition OFF, and all vehicle systems OFF. Disconnect the harness
connector at the M45 Rear Wiper
Motor. It may take up to 2 min for all vehicle systems to power down.
- Test for less than 10 ohms between the ground circuit terminal 3 and
ground.
If 10 ohms or greater
- Test for less than 2 ohms in the ground circuit end to end.
- If 2 ohms or greater, repair the open/high resistance in the circuit.
- If less than 2 ohms, repair the open/high resistance in the ground
connection.
If less than 10 ohms
- Ignition ON.
- Verify a test lamp illuminates between the B+ circuit terminal 2 and
ground.
- If the test lamp does not illuminate
- Ignition OFF, remove the test lamp. Disconnect the X2 harness connector
at the X50A Fuse Block -
Underhood.
- Test for less than 2 ohms in the control circuit end to end.
- If 2 ohms or greater, repair the open/high resistance in the circuit.
- If less than 2 ohms, test or replace the X50A Fuse Block - Underhood.
If the test lamp illuminates
- Connect a test lamp between the control circuit terminal 1 and ground.
- Verify the test lamp does NOT turn ON and OFF when commanding the rear
wiper ON and OFF with the
rear wiper switch.
If the test lamp turns ON and OFF
Test or replace the M45 Rear Wiper Motor.
If the test lamp does not turn ON and OFF
- Ignition OFF, connect the harness connector at the M45 Rear Wiper Motor.
Disconnect the X2 harness
connector at the X50A Fuse Block - Underhood, It may take up to 2 min for
all vehicle systems to power
down.
- Test for less than 10 ohms between each ground circuit terminal listed
below and ground:
If 10 ohms or greater
- Test for less than 2 ohms in the ground circuit end to end.
- If 2 ohms or greater, repair the open/high resistance in the circuit.
- If less than 2 ohms, repair the open/high resistance in the ground
connection.
If less than 10 ohms
- Ignition ON.
- Verify the M45 Rear Wiper Motor is not activated.
If the M45 Rear Wiper Motor is activated
- Ignition OFF, disconnect the harness connector at the M45 Rear Wiper
Motor, ignition ON.
- Test for less than 1 V between the control circuit terminal 1 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the M45 Rear Wiper Motor.
If the M45 Rear Wiper Motor is not activated
- Connect a 20 A fused jumper wire between both of the circuits listed
below and B+.
- B+ Circuit Terminal H4
- Control Circuit Terminal H3
- Verify the M45 Rear Wiper Motor activates
If the M45 Rear Wiper Motor does not activate
- Ignition OFF, remove the jumper wire, disconnect the harness connector
at the M45 Rear Wiper
Motor, ignition ON.
- Test for infinite resistance between the control circuit and ground.
- If less than Infinite resistance, repair the short to ground on the
circuit.
- If infinite resistance
- Test for less than 2 ohms in the control circuit end to end.
- If 2 ohms or greater, repair the open/high resistance in the circuit.
- If less than 2 ohms, replace the M45 Rear Wiper Motor.
If the M45 Rear Wiper Motor activates
- Ignition OFF, connect the X2 harness connector at the X50A Fuse Block -
Underhood. Disconnect the X4
harness connector at the K9 Body Control Module, ignition ON.
- Verify the M45 Rear Wiper Motor is not activated.
If the M45 Rear Wiper Motor is activated
- Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block
- Underhood, ignition
ON.
- Test for less than 1 V between the control circuit terminal 10 and
ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the X50A Fuse Block - Underhood.
If the M45 Rear Wiper Motor is not activated
- Connect a 10 A fused jumper wire between the control circuit terminal 10
and B+.
- Verify the M45 Rear Wiper Motor activates.
If the M45 Rear Wiper Motor does not activate
- Ignition OFF, remove the jumper wire, disconnect the X2 harness
connector at the X50A Fuse
Block - Underhood.
- Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the
circuit.
- If less than infinite resistance
- Test for less than 2 ohms in the control circuit end to end.
- If 2 ohms or greater, repair the open/high resistance in the circuit.
- If less than 2 ohms, test or replace the X50A Fuse Block - Underhood.
If the M45 Rear Wiper Motor activates
- Test or replace the K9 Body Control Module.
Component Testing
Windshield Wiper/Washer Switch
- Ignition OFF, disconnect the harness connector at the S82 Windshield
Wiper/Washer Switch.
- Test for infinite resistance between the signal terminal 4 and the low
reference terminal 2 with the rear
wiper switch in the OFF position.
If less than infinite resistance
Replace the S82 Windshield Wiper/Washer Switch.
If infinite resistance
- Verify the resistance is within the range specified below between the
signal circuit terminal 4 and the low
reference circuit terminal 2 by cycling the switch between Rear Wiper
position and Rear Washers
position.
- Rear Wiper : 624-644 ohms
- Rear Wiper Sweep : 1.8-2.2 kohms
- Rear Washer : 5.9-6.4 kohms
If not within the specific range
Replace the S82 Windshield Wiper/Washer Switch.
If within the specific range
- All OK
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Rear Window Wiper Motor Replacement
- Front Compartment Fuse Block Replacement
- Windshield Wiper and Washer Switch Replacement (Encore), Windshield
Wiper and Washer
Switch Replacement (Trax)
- Control Module References for body control module 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:
Removal Procedure
WARNING: Do not attempt to repair or alter the head impact
energy-absorbing
material glued to the headliner or to the garnish trims. If the material
is damaged, replace the headliner and/or the garnish trim. Failure to
do so could result in personal injury.
CAUTION: If a vehicle i
Special Tools
CH-44721 Power Steering Analyzer
For equivalent regional tools, refer to Special Tools.
Rack and Pinion System
Fig. 3: Testing Rack and Pinion System Pressures
Test Description
The numbers below refer to the step numbers on the diagnostic table.
5
This step tests the system for r