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 02
- Front Washer Relay Circuit Short to Ground

Diagnostic Fault Information





Circuit/System Description

The body control module (BCM) controls the windshield washer fluid pump based on an input from the window 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 front 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 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 X2 harness connector at the X50A underhood fuse block.
2. Disconnect the X4 harness connector at the K9 BCM.
3. Ignition OFF, test for less than 5 ohm between the signal circuit terminal 60 at the X50A underhood fuse block and the signal circuit terminal 14 at the K9 BCM.

• If the value is greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the K9 BCM.

4. If all circuits test normal, test or replace the X50A underhood fuse block.

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 underhood fuse block.
If the KR11 windshield washer pump relay works, but the G24 windshield washer pump does not run, test the washer fluid pump control circuit and the washer fluid pump ground 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.

* Control Module References (Programming and Relearning) for BCM replacement, setup, and programming
* Windshield Washer Pump Replacement (Service and Repair)