B3873

DTC B3873

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions)provides an overview of each diagnostic category.

DTC Descriptors
DTC B3873 01
- Front Washer Relay Circuit Short to Battery

DTC B3873 02
- Front Washer Relay Circuit Short to Ground

DTC B3873 04
- Front Washer Relay Circuit Open Circuit

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) controls the windshield washer fluid pump based on an input from the windshield wiper/washer switch. The BCM monitors the washer switch through the windshield washer switch signal circuit. When the wash switch is closed, ground is supplied to the windshield washer switch signal circuit. When this is the case, the BCM will command the windshield washer fluid pump and the low speed wipers on.

Conditions for Running the DTC

* Ignition ON.
* The system voltage is between 9-16 V.

Conditions for Setting the DTC

* A short to ground or an open/high resistance is detected in the windshield washer relay control circuit.
* A short to voltage is detected in the windshield washer relay control circuit.

Action Taken When the DTC Sets

Washer operation is suspended.

Conditions for Clearing the DTC

A current DTC clears when the diagnostic runs and passes.

Reference Information
Schematic Reference

Wiper/Washer Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
Description and Operation

Wiper/Washer System Description and Operation (Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the KR11 windshield washer pump relay.
2. Test for less that 5 ohm between the ground circuit terminal 85 and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Install a test lamp between the control circuit terminal 86 and ground.
4. Command the washers ON using the S82 windshield wiper/washer switch.

• If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

5. If all circuits test normal, replace the KR11 windshield washer pump relay.

Component Testing

Output Control Tests

Ignition ON, command the Windshield Washer Relay Command ON and OFF with a scan tool. Observe that the KR11 windshield washer pump relay clicks and the G24 windshield washer pump runs.

If the KR11 Windshield Washer Pump Relay does not work, replace the X50A fuse block - underhood.
If the KR11 Windshield Washer Pump Relay works, but the G24 windshield washer pump does not run, test the control circuit.
If all circuits test normal, replace the G24 windshield washer pump.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Front Compartment Fuse Block Housing Replacement (Front Compartment Fuse Block Housing Replacement)
* Windshield Washer Pump Replacement (Windshield Washer Pump Replacement)
* Control Module References (Programming and Relearning)for BCM replacement, programming and setup