DTC B2750
DTC B2750 |
Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
has overviews of all diagnostic categories.
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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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
Horn Switch Signal
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1
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2
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2
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-
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Horn Relay Control
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B2750 02
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B2750 04
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B2750 01
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-
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Horn Control
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2
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2
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1
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-
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Horn Ground
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-
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2
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2
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-
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1. Horn Always On
2. Horn Inoperative |
Circuit/System Description |
The body control module (BCM) provides a ground for the Horn printed circuit board (PCB) relay within the underhood fuse block. The underhood fuse block will then provide B+ voltage to the horn control circuit, sounding the horn.
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 horn will be inoperative.B2750 02
The horn will sound continuously until the horn is disconnected or when the horn overheats and becomes inoperative.Conditions for Clearing the DTC |
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The DTC clears when the fault is no longer detected.
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The current DTC will become history when the request for the output is removed.
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The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.
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Reference Information |
Schematic Reference
Horn Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Horns System Description and Operation
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for information on diagnostic tools
Circuit/System Verification |
Ignition ON, command the P12 Horn ON and OFF with the scan tool. The horn should turn ON and OFF when changing between the commanded states.
Circuit/System Testing |
1. |
Ignition OFF, disconnect the X2 harness connector at the X50A Fuse Block - Underhood.
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2. |
Connect a test lamp between the X2 harness connector control circuit terminal 25 and B+.
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3. |
Ignition ON, command the P12 Horn ON and OFF with the scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
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4. |
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 K9 Body Control Module.
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5. |
If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module.
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6. |
If all circuits test normal, replace the X50A Fuse Block - Underhood.
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Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
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Underhood Electrical Center or Junction Block Replacement
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Control Module References
for information on BCM replacement, setup, and programming
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