DTC B3874 V8
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 Wiper Motor Relay Coil Supply Voltage | B3874 | 2 | 6 | -- |
Windshield Wiper Switch High Signal | 6 | 4 | 1 | -- |
Windshield Wiper Switch Low Signal | 6 | 3 | 1 | -- |
Windshield Wiper Motor Park Switch Signal | 5 | 5 | -- | -- |
Windshield Wiper High Speed Relay Control | 7 | 4 | B3875 | -- |
Windshield Wiper Motor High Speed Control | 2 | 4 | -- | -- |
Windshield Wiper Motor Low Speed Control | 2 | 3 | -- | -- |
Wiper PCB Relay Ground | -- | 2 | -- | -- |
Windshield Wiper Motor Ground | -- | 2 | -- | -- |
Windshield Wiper Switch Ground | -- | 1 | -- | -- |
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) controls and monitors the state of the wiper relay control circuit. When the windshield wiper switch is placed in to a low speed setting, a signal is applied to the BCM. The BCM then applies battery positive voltage to the coil side of the WIPER PCB Relay through the wiper relay control circuit. This energizes the relay, applying battery positive voltage from the WPR fuse through the switched side of the relay to the windshield wiper motor. Ground is applied at all times to the coil side of the wiper relay and the windshield wiper motor form G201.
Conditions for Running the DTC
| • | The ignition is in the ON position. |
| • | The ignition voltage is between 9-16 volts. |
Conditions for Setting the DTC
| • | The BCM detects an short to battery positive voltage in the wiper high speed relay control circuit for over 1 second. |
| • | The BCM detects an open or a short to ground in the wiper high speed relay control circuit for over 1 second. |
Action Taken When the DTC Sets
The BCM will not activate the output.
Conditions for Clearing the DTC
| • | The DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present. |
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Wiper/Washer System Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Testing
- Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
- Connect a test lamp between the control circuit terminal A1 and battery voltage.
- Command the Wiper PCB 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 underhood fuse block.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. 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 voltage or an open/high resistance. If the circuit tests normal, replace the body control module. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
DTC B3874 V6
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 Wiper Motor Relay Coil Supply Voltage | B3874 | 2 | 6 | -- |
Windshield Wiper Switch High Signal | 6 | 4 | 1 | -- |
Windshield Wiper Switch Low Signal | B3922 00 | 3 | 1 | -- |
Windshield Wiper Motor Park Switch Signal | 5 | 5 | -- | -- |
Windshield Wiper High Speed Relay Control | 7 | 4 | B3875 | -- |
Windshield Wiper Motor High Speed Control | 2 | 4 | -- | -- |
Windshield Wiper Motor Low Speed Control | 2 | 3 | -- | -- |
Wiper PCB Relay Ground | -- | 2 | -- | -- |
Windshield Wiper Motor Ground | -- | 2 | -- | -- |
Windshield Wiper Switch Ground | -- | 1 | -- | -- |
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) controls and monitors the state of the wiper control circuit. When the windshield wiper switch is placed in to a low speed setting, a signal is applied to the BCM. The BCM then applies battery positive voltage to the coil side of the wiper relay through the wiper relay control circuit. This energizes the wiper relay, allowing battery positive voltage from the wiper/ws fuse through the switched side of the wiper relay to the windshield wiper motor. Ground is applied at all times to the coil side of the wiper relay and the windshield wiper motor form G201.
Conditions for Running the DTC
| • | The ignition is in the ON position. |
| • | The ignition voltage is between 9-16 volts. |
Conditions for Setting the DTC
| • | The BCM detects an short to battery positive voltage in the wiper high speed relay control circuit for over 1 second. |
| • | The BCM detects an open or a short to ground in the wiper high speed relay control circuit for over 1 second. |
Action Taken When the DTC Sets
The BCM will not activate the output.
Conditions for Clearing the DTC
| • | The DTC will clear on current status after the condition for setting the fault is corrected. |
| • | A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer 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 Referencesfor scan tool information.
Circuit/System Verification
Ignition ON, wiper switch in the Low position. Verify the windshield wipers are cycling at the low speed.
Circuit/System Testing
- Ignition OFF, disconnect the Wiper Relay.
- Connect a test lamp between the control circuit terminal 85 and ground.
- Ignition ON, command the Low speed wipers ON and OFF using the wiper switch. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the WIPER Relay.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to Voltage. If the circuit tests normal, replace the 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 BCM. |
Component Testing
Relay Test
- Ignition OFF, disconnect the WIPER Relay.
- Test for 60-200 ohms between terminals G14 and E15.
- Test for infinite resistance between the following terminals:
- Test for less than 2 ohms between terminals G15 and F14.
- Install a 10A fused jumper wire between relay terminal G14 and 12 volts. Install a jumper wire between relay terminal E15 and ground. Test for less than 2 ohms between terminals G15 and E14.
| ⇒ | If the resistance is not within the specified range, replace the relay. |
| • | G15 and E15 |
| • | G15 and E14 |
| • | G15 and G14 |
| • | G14 and E14 |
| ⇒ | If not the specified value, replace the relay. |
| ⇒ | If greater than the specified range, replace the relay. |
| ⇒ | If greater than the specified range, replace the WIPER Relay. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
