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 Descriptors
DTC B2750 01
-
Horn Relay Secondary Circuit Short to Battery
DTC B2750 02
-
Horn Relay Secondary Circuit Short to Ground
DTC B2750 04
-
Horn Relay Secondary Circuit Open
Diagnostic Fault Information
Circuit/System Description
The body control module (BCM) provides a ground for the Horn PCB relay within the underhood fuse block. The underhood fuse block will then provide B+ voltage to the horn control circuit, sounding the horns.
Conditions for Running the DTC
When the horn output is actively being requested by the BCM.
Conditions for Setting the DTC
B2750 01
The BCM detects a short to voltage in the horn relay control circuit.
B2750 02
The BCM detects a short to ground in the horn relay control circuit.
B2750 04
The BCM detects an open/high resistance in the horn relay control circuit.
Action Taken When the DTC Sets
B2750 01, B2750 04
The horns will be inoperative.
B2750 02
The horns will sound continuously until the horns are disconnected or when the horns overheat and becomes inoperative.
Conditions for Clearing the DTC
* The DTC clears when the fault is no longer detected.
* 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 Fuel Pump and Level Sensor Assembly
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 Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON.
2. Verify the operation of the horn when commanding the Content Theft Deterrent Alarm Trigger Horn Relay ON and OFF with a scan tool.
• If the horn is always ON or always OFF
Refer to Circuit/System Testing.
• If the horn turns ON and OFF
3. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the X5 harness connector at the K9 body control module.
2. Ignition ON.
3. Test for greater than 10 V between the control circuit terminal 19 and ground.
• If 10 V or less
1. Ignition OFF, disconnect the harness connector at the X50A fuse block-underhood.
2. Test for infinite resistance between the control circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the X50A fuse block-underhood.
• If greater than 10 V
4. Replace the K9 body control module.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Accessory Wiring Junction Block Replacement Removal and Replacement
* Control Module References Control Module References for BCM replacement, setup and programming