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 Descriptor
DTC B3873 00
- Front Washer Relay Circuit

Diagnostic Fault Information





Circuit/System Description

The windshield washer function is controlled by the body control module (BCM). When the washer switch is pressed, ground is applied through the switch contacts and the signal circuit to the BCM indicating the wash request. The BCM then applies ground through the control circuit to the coil side of the WS WASH relay energizing the relay. With the relay energized, battery voltage from the WPR fuse is applied through the switch contacts of the relay, the WSW fuse and the control circuit to the windshield washer fluid pump.

Conditions for Running the DTC

This DTC can set only when the output is actively being requested by the BCM.

Conditions for Setting the DTC

This DTC sets if the BCM detects a short to ground in the wiper high speed relay control circuit.

Action Taken When the DTC Sets

The BCM will not activate the output.

Conditions for Clearing the DTC

* The current DTC will become history when the request for the output is removed or when the condition for setting the fault is corrected.
* The history DTC will clear after 50 consecutive ignition cycles without a fault present.

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 harness connector at the windshield washer fluid pump.
2. Verify there is less than 2ohm between ground terminal B and ground

• If not the specified value, test the ground circuit for an open/high resistance.

3. Connect a test lamp between the control circuit terminal A and ground.
4. Command the Wiper Washer Motor ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to B+. If the circuit tests normal, replace the body control module.
• 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 body control module.

5. If all circuits test normal, test or replace the underhood fuse block.

Repair Instructions

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

* Accessory Wiring Junction Block Replacement (Accessory Wiring Junction Block Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming