B3874

DTC B3874

Circuit 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 G200.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3874 Wiper Low Speed Relay Circuit

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 following conditions will cause the DTC to set:

* The BCM detects an short to battery positive voltage in the WIPER relay control circuit for over 1 second.
* The BCM detects a short to ground or an open 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 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 without a fault present.
* History and current DTCs can be cleared using a scan tool.

Diagnostic Aids

Step 1 - Step 10:

Perform a visual inspection for loose or poor connections at all related components. refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics