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 B3874 00: Wiper Low Speed Relay CircuitDiagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Windshield Washer Switch Signal | 6 | -- | 1 | -- |
Windshield Wiper Switch High Signal | 6 | 4 | 1 | -- |
Windshield Wiper Switch Low Signal | 3 | 3 | 1 | -- |
Windshield Wiper Motor Park Switch Signal | 5 | 5 | -- | -- |
Windshield Wiper Motor High Speed Control | 2 | 4 | -- | -- |
Windshield Wiper Motor Low Speed Control | 2 | 3 | B3874 00 | -- |
Windshield Wiper Motor Ground | -- | 2 | -- | -- |
Windshield Wiper Switch Ground | -- | 1 | -- | -- |
Wiper High Speed Relay Control | 7 | 4 | B3875 00 | -- |
Wiper Relay Ground | -- | 2 | -- | -- |
1. Wipers and Washers Inoperative All Modes 2. Wipers Inoperative All Modes and Washers Work 3. Delay or Low Speed Wipers Inoperative 4. High Speed Wipers Inoperative 5. Wipers Do Not Park 6. Wipers Always On 7. Wipers Operate at High Speed in the Low Speed Mode | ||||
Circuit/System Description
The body control module (BCM) monitors the wiper Low speed relay control circuit only when wiper Low speed mode is active. When the wiper Low speed mode is requested, the BCM responds by applying a ground through the wiper Low speed relay control circuit to the coil side of the relay, energizing the WPR Relay.
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 battery voltage in the wiper 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
Connector End View Reference
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, remove the WPR Relay from the underhood fuse block.
- Connect a test lamp between the wiper Low speed relay control circuit terminal 86 and battery voltage.
- Ignition ON, command the Wiper Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the WPR relay.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, test or replace the BCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, test or replace the BCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for BCM replacement, setup, and programming
