B2750

DTC B2750

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 B2750 01
- Horn Relay Coil Circuit Short to Battery

Diagnostic Fault Information





Circuit/System Description

The Vehicle Interface Unit (VIU) controls the horn relay by grounding the control circuit of the horn relay coil energizing the relay. When the horn relay is energized, the horn relay contacts close applying voltage through the horn fuse and the horn control circuit to the horns.

Conditions for Running the DTC

When the horn output is actively being requested by the VIU.

Conditions for Setting the DTC

This DTC is set if the VIM attempts to assert its HORN RELAY CONTROL output to the low voltage state, but senses that the output remains in the high voltage state.

Action Taken When the DTC Sets

The VIU disables the output to the horn relay until the next ignition cycle.

Conditions for Clearing the DTC

* The current DTC will become history when the request for the output is removed.
* The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Reference Information
Schematic Reference

Horn Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Horns 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 Verification

Command the horns ON and OFF with the scan tool. The horns should turn ON and OFF when changing between the commanded states. Refer to Symptoms - Horns (Symptoms - Horns)

Repair Instructions

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

Control Module References (Programming and Relearning)for VIU replacement, setup and programming